DE P GUI M OLD BUYERSTI Fi nd a m ol dm akerat :www. am ba. org
Mold Buyer’s Tip Guide Table of Contents Article
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Tips to Make the Mold Buying Process Easier……………………………………….1 What to Look for in a Mold Supplier………………………………………………….2 When to Use Hot Runner Systems…………………………………………………….3 Prototype Tooling – Is it Worth the Added Costs? ........................................................4 Getting the Moldmaker Involved Early………………………………………………..6 Why Minor Changes in a Part/Mold Design Could Result in Major Costs Increases…7 Selecting the Optimum Type of Mold for your Part………………………………….. 9 Does Off-shoring Molds Still Make Sense? ..................................................................10 Typical Mold Materials: Which One is Right for the Mold You Require? …..…….…11 What Constitutes a Good, High-Production Mold? .......................................................12 Determining the Number of Cavities in a Mold? ….…………………….……………13 Ten Pointers for Better Mold Production ………………………………………………14 Advantages of U.S. Molds………………………………………………………………15 Appendix A - What Characterizes a Good, High-production Mold? Appendix B – Part Production by Mold Cavities Charts Appendix C - Finding the Total Cost of Your Mold Worksheet AMERICAN MOLD BUILDERS ASSOCIATION 3601 Algonquin, Suite 304 Rolling Meadows, IL 60008 847.222.9402 fax 847.222.9437
Find a moldmaker at: www.AMBA.org
Tips to Make the Mold Buying Process Easier
from the start so the moldmaker knows what you expect. 6. Make your payments on time per the agreement. Few moldmakers can afford to play banker, and building a mold entails many, sometimes large, up-front expenses on their part. There are a number of ways to approach the payment schedule, such as 30% down, 30% at half completion, 30% at completion, and 10% upon part approval and mold shipment. Different moldmakers have different plans, or will work with you on a payment schedule that is fair, equitable and will benefit both companies.
Buying a mold is a complex and sometimes tedious process, but a few rules can help make the process easier. They’re not written in stone, but you’ll find that to most moldmakers they are gospel. 1. Send an RFQ that is as detailed as you can make it. Don’t make the moldmaker guess what you want. Moldmakers are a lot of things, but mind-readers they’re not! Be specific about the type of mold, the number of cavities, the steel, expectations of mold life, and any guarantees you’ll need. If you aren’t certain about any of these items, get input from your moldmaker to help you determine exactly what type of mold is best for your requirements. The more detailed the RFQ, the more accurate the moldmaker’s quote will be.
7. Changes to the part design can mean changes to the mold. Remember, the more changes you make during the mold build, the less likely you are to get a mold in the lead time or at the price quoted. Understand that when you require part design changes, it often leads to changes in the mold design, which can add both time and cost to the mold build.
2. Be honest about why you are requesting a quote. If you need a ballpark figure to submit to marketing, say so. But don’t ask for a complete engineering evaluation and quote, then casually mention it’s just a preliminary quote on a project that’s at least a year away. Or you’re just fishing. Quoting is time-consuming, and moldmakers want to spend their time quoting jobs that have good promise of becoming a reality soon.
8. Define up front when the mold is considered complete. When is a mold complete? That often determines when final payment is made. Is the mold complete upon approved part sample? Upon shipment? Usually a mold is complete when it is capable of producing a part according to specifications and dimensions on the part print. Most moldmakers will make small changes and tweaks to get the mold to spec to make the part according to print dimensions. A decision to make a change to the part, and consequently to the mold, after the part has met print specs doesn’t mean the mold isn’t finished. When the part meets print specifications and dimensions, the mold is complete. Changes are done via an ECO (engineering change order) and will be priced accordingly.
3. Respect the intellectual property of the moldmaker. The knowledge and creativity a moldmaker has acquired are his or her intellectual property. Keep those ideas and suggestions confidential when going out for quote. If you choose another mold shop to do the work, don’t tell moldmaker “B” to make it the way moldmaker “A” suggested in his quote. Remember, moldmaker “B” didn’t quote it that way and may not understand why moldmaker “A” made that suggestion.
9. If it sounds too good to be true, it probably is. You may find a moldmaker who quotes very low prices on a job. Maybe he’s hungry, or maybe his overhead is low so he can price lower than other shops. However, any quote that comes in too low might not be the bargain is appears to be.
4. Consider the benefits of forming a true partnership with your moldmaker(s). Bring in him or her early on your project for input; work with him in regard to costing goals and budgets; life of the project and part quantity expectations. Moldmakers don’t like being mushrooms! The best purchasing is done by those who truly know their suppliers and play as a team, openly and honestly, to the benefit of both companies.
10. Offshore molds are often not the bargain they seem to be. With the increased interest over the past decade in buying molds offshore, from China or other Asian countries, there is an increased need to be more cautious. Most OEMs that choose a moldmaker in China, for example, do so because the price of the mold can be 30-50% less than the price for a U.S. built mold. However, price doesn’t always equal cost. Things to consider are intellectual property and confidentiality issues; the cost of travel (air fare, hotel, per diem, etc.)
5. Communicate with and solicit communication from your moldmaker on a regular basis. Many provide Gantt charts or other types of progress reports online, or provide online access to regularly posted updates. Knowing where the mold build stands and if it is on schedule is critical, so request scheduled information
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and time away from the company for an engineer to oversee the mold build; the cost of shipping a large mold from Asia to the U.S.; the cost of engineering change orders that a U.S. moldmaker will have to do (you won’t be shipping a mold back and forth across the Pacific Ocean for rework and ECOs!); and the cost of the mold’s productivity and efficiency, and maintenance over the life of the program.
molded over it. (Think toothbrush handle.) •
Two-shot molds: mold which are built to accommodate multi-material molding or multicolor molding, such as an automotive tail light, which might require both red and orange polycarbonate material to be molded for a complete tail light.
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Rotary Stack Molds: molds that produce multiple parts that require multiple processes. The mold is built in a “cube” and after each process the mold rotates 90 degrees for the next process. This is for highly complex components requiring both multi-material or multiple steps to complete, but the result is a final, completed and assembled unit. Eliminates secondary operations, multiple steps after molding or multiple molds to make a complete unit.
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Unscrewing molds: molds that accommodate threaded parts such as screws, caps and closures, and generally have either id or od threads.
When purchasing a mold, it’s especially true that you get what you pay for. Your molded components are only as good as the mold they come from, so be sure your mold is optimum to mold the parts you need for the life of the program. Excerpted from “Purchasing Injection Molds: A Buyer’s Guide”, by: Clare Goldsberry ■■■■■■■■■■■■■■■
What to Look for in a Mold Supplier When engineering comes to purchasing with a requirement for a mold for a new plastic component or a group of components for a new product, many times the purchasing person isn’t knowledgeable enough about purchasing molds to know where to go for the requirement. In some companies, project or product engineers are in charge of finding a mold manufacturer, but even then there are questions about what to look for in a mold supplier.
Some mold manufacturers specialize in very large-sized molds such as those that would be used for bumpers on cars or trucks. Some specialize in very small molds for micro-molding. Most fall somewhere in between, and can generally handle molds that fit up to a 500-ton injection molding press. Mold manufacturers also have market niches with which they have become wellacquainted with such as extremely high-cavity molds (128 cavities for example) for the packaging industry; or smaller cavitation molds for the medical industry; or very aesthetic molds for the cosmetics packaging industry.
Many purchasing people will go online as a first step, and there they will find a plethora of mold manufacturers. So how to pick the right one for the job? Most mold shops have similar machine tool capabilities and CAD/CAM software systems. Where the differences come into play are the mold types in which different shops specialize. Some of the types of molds include: •
Insert Molds: molds which accommodate inserts (either robotically or manually inserted) which the plastic is molded around to eliminate secondary or post-molding operations.
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Overmolding molds: molds which accommodate placement of a substrate part over which another material is molded, i.e. an ABS substrate with a thermoplastic elastomer (TPE)
Mold manufacturers develop certain areas of expertise over their years in business, and generally are more successful when they stick to those areas of expertise. While it’s not impossible that a moldmaker that has only built smaller, 2, 4, 8 or 16-cavity molds could successfully build a 96-cavity medical mold, it’s best to find a mold manufacturing company that has a track record in building the type of mold that the OEM requires to help ensure everyone’s success. For example, a mold manufacturer might be good at large multi-cavity molds, but has never built an unscrewing mold for a cap application. There are mold manufacturers that specialize in building unscrewing molds and have built hundreds over the years. The opportunity for a successful build for a large, multi-
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When to Use Hot Runner Systems
cavity unscrewing mold from a shop experienced in this type of mold is much greater than one which has never built an unscrewing mold.
Hot runner (runnerless) systems are seeing more demand in today’s high-speed, high-volume molding operations due to higher material prices, a need to reduce cycle time, reduce scrap rates, and increase overall productivity and costs to manufacture, as compared to a “cold runner” system.
If the price sounds too good to be true . . . You’ve heard it before – it probably is. Mold manufacturers do not have “standardized” pricing, so if you go out for bid from several different mold companies, you’ll probably get several different prices which can range all over the map. Much of this price variable has to do with the expertise of the mold manufacturer in designing and building the type of mold you require. It also has to do with their shop rates, which can vary depending on the size of the shop or where the shop is located, and other variables. But beware of a mold price that sounds just too good to be true. This has happened when OEMs get China pricing. The price often comes in so low that it seems unbelievable. You will get what you pay for!
Particularly in applications in which regrind cannot be introduced (virgin resin only applications) back into the material to produce the parts, hot runner systems have an advantage in reducing the amount of material used as well as the amount of scrap created by the runner system. In the book, “What Is A Mold?” produced by Tech Mold Inc., a Tempe, AZ-based mold manufacturer, it says that a “hot runner system is used to eliminate or lessen the use of runners which must be removed from an injection mold with the molded parts. If runners are eliminated, the point of entry to the mold cavity (gate) will have a hot drop (nozzle) suspended in the gate area. This is necessary to retain controlled heat sufficient to promote continuous moldability in the drop area directly adjacent to the mold cavity.”
If you get quotes that are very wide in price, go talk to each moldmaker that submitted the bids and ask for a detailed explanation of the quote and how he/she arrived at that price. Make sure your RFQ contained all the detailed information about the mold’s requirements and that the moldmaker didn’t miss something that might have added cost to the mold. Moldmakers are human too, and none of them are mind-readers.
Tech Mold explains that the system has “a manifold suspended behind the drops” that is electrically heated, “as are the drops, in order to contain heat in the hot manifold assembly. The system is also suspended so as not to transfer unwanted heat into the rest of the mold. The mold itself is designed to dissipate heat in order to solidify the molded parts as quickly as possible to lower cycle times.”
Finding a good mold manufacturer that can meet your needs with a high-quality mold that will give you highquality parts isn’t rocket science, but doing your homework is important. That is why when you go to the member directory of the American Mold Builders Association at www.amba.org; you’ll find a listing of some 300 mold manufacturers, representing some of the best in the industry, with their specialties in mold types, markets, and much more. You can pre-qualify the company before you send out RFQs so that you are sure of getting “apples-to-apples” quotes. It will save you time and money in the long run.
Hot runner technology is becoming a “fully-accepted” and indeed the preferred method of gating many multicavity molds, says Bruce Catoen in his new book, “Selecting Injection Molds”. “They are replacing more and more of the older runner methods especially the 3plate systems. In fact, older, existing 3-plate molds can often be quite easily rebuilt into hot runner molds.”
About the author: Clare Goldsberry has 28 years experience in the plastics industry and has been a marketing/sales manager for molding/moldmaking companies. For the past 20 years, she has been writing about the plastics industry for the top industry trade magazines in North America. For more on this topic, write for her book: Purchasing Injection Molds: a buyer’s guide, available from the AMBA for just $25. Call 847-222-9402 for more information.
Catoen notes in his book that “Today, there are many well-established companies specializing in hot runners, who sell either the basic hardware (manifold, nozzles, heaters, etc.) or assembled hot runner systems, complete with all associated plates and other hardware ready to be joined to an otherwise complete mold built by the mold maker. All that is required for a purchase order is to specify the important interface dimensions and any production data such as plastic to be used and the mass of the product. These hot runner suppliers mass produce
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· Cooling time for thin sectioned parts is shorter due to the absence of thicker, longer cycledependent runners. · No need to provide robotics for runner removal. · Plasticized material (shot size) is reduced by the runner weight. · Lower injection pressures may be realized during packing stages due to heated gate areas in hot runner systems. · Less clamping pressure required versus two plate cold runner molds · Sprue sticking and nozzle freeze-off associated with cold runners is eliminated. · A cleaner molding room can be realized without dealing with regrind, an advantage particularly in clean-room molding environments.
the hardware items and use specialized methods and equipment to produce better quality system parts at lower costs. Such hot runners [systems] are then guaranteed to work in the new mold and eliminate the need for the mold maker to experiment and waste time and money trying to get a “home made” system to work.” While hot runner systems are typically used on large, multi-cavity molds (32-cavity and up), many companies are choosing to put hot runner systems on smaller multicavity molds (8- or 16-cavity) because of the increased productivity and reduced scrap. Catoen writes that “In some molds, often for smaller products with a large number of cavities, but also with larger ones, a combination of cold and hot runner systems can be of great advantage.
While hot runner systems typically add somewhere in the range of $40,000 - $60,000 to the cost of the mold, the advantages of using a hot runner system provide fairly fast payback in the right mold. However, Catoen writes, “There are still some molds for which the advantages cannot be justified economically, especially for low production items. In these cases, the older systems, especially cold runner 2-plate molds are still much in use.”
* It can eliminate a large portion of the cold runner and thereby significantly reduce the mass of plastic to be reground or lost. * There is much less pressure drop between the machine nozzle and the gates, because the pressure drop in the hot runner manifold is smaller than in a (long) cold runner. * It can be used when very small cavities cannot be located very close to each other, as a “pitch” (distance) for which there are no standard-spaced hot runner nozzles available, or where it is not possible or practical to use hot runner gates. Typically, a cluster of 2-6 (or even m ore) very small products can be gated from a small runner or a disk, which is fed from a hot runner drop.
If the OEM believes that they have an application that might be suitable for a hot runner system, they should consult with a mold manufacturer that is experienced in producing molds with hot runner systems. Most of the AMBA member companies build hot runner molds for customers in a variety of industries, and can help the OEM determine if the application will benefit from a hot runner system.
* It will shorten the cycle time. Large distributing (cold) runners take much longer to cool than the final runners feeding the cavities. Especially if the products cool rapidly, such heavy runners significantly slow down the molding cycle. The cold runner portion in such cases can be treated as any cold runner mold; it could be a 3-plate arrangement (rarely used) or a 2-plate system with edge or tunnel gates in the product.”
For more information contact Bruce Catoen at 905-8770185, Jerry Seidelman at Tech Mold Inc., 480-968-8691, or visit www.techmold.com or visit the AMBA web site at www.amba.org to locate a mold manufacturer. ■■■■■■■■■■■■■■■
Tech Mold’s book lists some of the advantages of a hot runner system vs. a cold runner system:
Prototype Tooling - Is it Worth the Added Costs?
· No runners to separate from the molded parts. · No runners to either dispose of or regrind and reprocess with the possibility of introducing contamination into the virgin material if being mixed with virgin. · Hot drops carry consistent heat at processing temperature directly into the cavity.
Many engineers wonder about the value of prototyping whether that involves rapid prototyping of parts using one of the many processes available (stereolithography SLA ; selected laser sintering - SLS; fuse deposition modeling - FDM), or Rapid Tooling (RT) that will mold
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Walter says that most often his customers want a prototype mold because they’re not sure if product will take off in the market. “So they start with an aluminum tool as a bridge tool until they get funding for the production mold or until they determine market requirements for the part,” he adds. MET Plastics has inhouse molding operations on presses ranging from 40720 tons.
parts in the actual polymer material. Typically, if OEMs want just one or two pieces to prove out the design, they’ll use SLA or some other rapid prototype process. But just how valuable is prototype tooling? Should you spend the additional money to have a prototype mold built to produce parts in the actual resin required? Prototype tooling can be wise investment if you’re unsure of the part’s functionality or moldability, or even whether or not the marketing group will like the design or ergonomics of the new product. Especially if you’re going to be molding millions of units it’s important to get it right.
But building an aluminum “bridge” tool often ends up being the production tool, as OEMs continue to use the aluminum mold for production parts. Walter says the oldest aluminum mold they have was built as a prototype mold in 1971 to run parts molded from glass-filled Lexan. “We’re still running 5,000 parts a year off that mold,” he chuckles. “That’s a bit extreme, but we continue to use bridge tools to mold 50,000-75,000 units a year. That’s very common to use the prototype mold for low-volume production.”
Pre-production tooling can be helpful in defining a part’s form, fit and function, allowing the OEM’s engineers and the moldmakers engineers to collaborate in a way that the OEM gets the part they need, prior to building a high-cavitation mold. Most mold manufacturers offer a variety of methods to achieve the OEM’s goals: prototype parts can be helpful and a cost effective way to test form and fit, and while not always in the polymer material that is ultimately required, provides a “touchyfeely” part that helps with initial evaluation. Some rapid prototype equipment makers are developing a wider range of materials however, that offer a greater opportunity to prototype in the end-use material. There are many options available to produce prototype parts, and many mold shops have a partnership with a service bureau if they do not have rapid prototyping in-house.
A prototype mold can help eliminate surprises at a lower cost than building a hardened steel production tool. OEMs can qualify that the part can be molded to their requirements, or they might find a part doesn’t meet the mechanical requirements, or aesthetically the part isn’t what they expected. “It absolutely helps the whole engineering process,” says Walter. Over the years, he notes, the requirement for prototype parts has dropped because people are doing simulated FEAs with computer software, so they don’t have the expense of prototype tooling.
Another prototype method is to build a core and cavity in either Direct Metal Laser Sintering process or in “soft” tooling (P-20 or aluminum). Many OEMs prefer building a pre-production mold or “bridge” mold that can that can be expanded to accommodate production molding. A pre-production mold can consist of a single core and cavity in a larger base, which can then be expanded to accommodate four or eight cavities when the part meets the requirements.
Tech Mold Inc. ( Tempe, AZ ) established an R&D center a few years ago to help customers with their prototype requirements, which Tech Mold calls “preproduction” molds. The advantage of Tech Mold’s dedicated R&D facility to customers is having the ability to design and build dimensionally correct pre-production molds, quickly and cost-effectively, while taking the lessons learned in the design and development stages to the multi-cavity production mold when the customer is ready.
Many OEMs choose to build soft tools to qualify the molded part, and then run several hundred or even several thousand pieces. MET Plastics Inc. ( Elk Grove, IL ) specializes in aluminum tooling for prototype, short and medium production runs. “Absolutely prototype molds are worth the cost,” says Mike Walter, vice president of MET Plastics. “If the OEM wants to qualify molded part designs and do their quality checks with all the inherent stresses of an actual molded part, or if they need to run several hundred pieces, or perform multiple design modifications, it’s worth the cost of that extra step to do a prototype mold.”
“Developmental prototype molds offer the customer greater opportunity to have true-to-spec, dimensionallycorrect parts in hand, while at the same time laying the groundwork of critical manufacturing information for the multi-cavity production mold to reduce mold-build time and costs,” said Brad Bollech, Tech Mold’s R&D manager. A customer came to Tech Mold with a four-part assembly, one of those parts being a 2-shot component, along with 300 molded parts that needed to be delivered
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personnel who are knowledgeable in plastic part design as well as mold design, including design for manufacturability.
in six weeks that met all dimensional and quality criteria so the customer could perform a marketing study on the new product. Rather that manufacturing separate prototype and production molds, which would result in longer lead times and higher costs, Tech Mold R&D offered a quick, short-term solution with a long-range approach. Knowing their customer’s needs would not require multiple tools in multiple presses, Tech Mold R&D’s approach was to design and build a custom mold with five molding stacks into one mold base in order to be aggressive in lead time and cost, while giving the customer the advantage of being able to scale up to a production mold when required.
Many OEMs are not aware of the knowledge base that exists in many mold companies, and the opportunities that offer the OEM to utilize that knowledge base to design and develop optimum parts and molds that will, in the long run, save time and money. In fact, the mold manufacturer can become a part of the OEM’s manufacturing team. Wade Clark, president of Electroform Company Inc. in Rockford, IL , believes that early involvement with the moldmaker is key to the success of any program. “We’re an extension of our customers’ R&D operations,” he states. “Our early involvement helps customers reduce their product launch time.”
“We designed and built a high-quality prototype mold that provided parts meeting all the dimensional and quality criteria,” said Bollech. “Manufacturing custom molding stacks to be interchangeable in a single mold base for the pre-production mold allowed us to maintain greater precision and flexibility of design as well as the ability to change out molding stacks in the press in 10-15 minutes.” “This hybrid approach of manufacturing quality prototypes that deliver production quantities means reduced capital expenditure for our customer’s entire program,”Bollech said.
It doesn’t matter how great your part design is if it can’t be molded. Your first step should be to take your concept model (3D computer model or prints or an SLA model) and sit down with your mold maker’s engineering team and get input on the part design. Can you really do what you think you want to do in manufacturing this part?
It’s obvious that building a prototype mold or “bridge” tool is worth the extra cost up front on a project in which there are still many unanswered questions, and where much collaboration will need to happen between the OEM’s engineers and the mold company’s engineers. It’s far more cost effective to get it right in a soft tool, and then produce a multi-cavity hardened tool, if that’s what’s needed, than to continually re-cut hardened cores/cavities trying to get it right after the fact.
Is this part moldable? If so, what type of molding process is optimum? Injection molding or thermoforming? Blowmolded or rotationally molded? Are there design issues that would make this part more ideal for one process than another? Are there design issues that will increase the cost of the mold? Can those design issues be resolved in some way to reduce the cost of the mold? Working from the outset with the moldmaker can save you a lot of money and time going forward. Some OEMs work directly with the molder and it is then the molder that works with the moldmaker. Or in some cases, the molder has in-house moldmaking capabilities which then put the entire project under one roof, which has benefits. If however, the molder doesn’t have mold manufacturing capabilities and must sub-contract the moldmaking that makes the molder a “middle-man” in the project, which often adds a layer of complexity to managing it.
[For more information on Rapid Tooling methods see April’s Injection Molding Magazine at imm.plasticstoday.com/imm/articles/rapidtools0409] By: Clare Goldsberry ■■■■■■■■■■■■■■■
Getting the Moldmaker Involved Early
Innovation Mold & Design Inc., Germantown, WI , specializes in early involvement with the OEM. Dan Fairbanks, President, says that his company begins with part design assistance. “The OEM might have concept drawings, but maybe doesn’t know if that design is manufacturable from an injection molding standpoint,” Fairbanks says.
A successful mold manufacturing program involves strategic planning, and one of the most important aspects of that plan is getting the mold manufacturer involved in the process early in the game. Most mold manufacturing companies today are fully staffed with engineering
Fairbanks always recommends that customers get an
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designers work closely with our customers’ design engineers we develop solutions in a collaborative way, improving not only the part but the mold to produce that part as well; a mold that will perform better, save time and bottom line - reduce costs. Keeping an open line of communication and staying involved in the development process avoids potential issues from being easily overlooked.”
SLA functional prototype part made first to make sure the components fit. “You can choose not to get an SLA prototype part, but if you don’t we’re not responsible for the end product,” says Fairbanks . The next step is to decide on the actual plastic material to be used in the end product based on criteria for use established by the OEM. Next, Innovation Mold will produce a prototype mold in P-20 steel, because prototypes often require a lot of engineering changes and P-20 accommodates welding and other necessary changes better than aluminum. Using P-20 steel and burning or machining the inserts right into the steel so the investment for Innovation Mold’s customers are just the inserts. The company has modular bases to accommodate a variety of inserts even 3-plate or hot-tip.
A challenging project recently completed by Innovation Mold took full advantage of early involvement and working collaboratively with the customer to optimize the outcome. This newly developed product required a complex tool that needed to be completed in a very short time frame, and had to stay within a tight budget. In addition to identifying and addressing any potential issues early on, Innovation Mold incorporated pioneering ideas. The end result delivered a 16-cavity; multi-slide tool in just eight weeks, and the tool’s performance exceeded the customer’s expectations. “To be as efficient as possible we need to invest in the latest design software and machine tool technology,” Fairbanks states. Early involvement in any new project is a key factor in allowing us to optimize our capabilities in a way that benefits the customers.” By: Clare Goldsberry
“Because of the way we make our prototype molds, we can do fast turnarounds, generally about two weeks, and then get the customer functional parts in their material,” Fairbanks explains. “We also have a molding machine here at our facility so that we can not only qualify the parts but we may be asked to run 10,000 to 20,000 parts once approval is given to fill the pipeline until the hardened steel production mold is built, which is another advantage of using P-20 steel.”
■■■■■■■■■■■■■■■ Because Innovation Mold works with the OEM from the outset, the entire program including the final production molds, can move forward much faster. Additionally, Innovation Mold provides all the information necessary for the molder, including CAD files, cycle time, shot weight, and other pertinent information. “When they go to the molder they are armed with all the information they need to get good piece part prices,” says Fairbanks .
Why Minor Changes in a Part/Mold Design Could Result in Major Cost Increases Let’s face it – changes in the part design and/or mold design are an inevitable part of the mold development and build process. Rarely is an engineering data file cast in stone from the outset, which is why good collaboration between the moldmaker and the OEM’s or molding company’s engineering team is required for a successful program. However, one important thing to remember is that the OEM or the molder for the OEM, can’t expect to make a lot of changes to the quoted part/mold design and not expect changes to the cost of the mold.
Fairbanks also believes that involving the moldmaker early in the project gives the OEM better control over the quality of the mold and hence, the molded parts. “You get what you pay for,” he says. Early involvement case study When Innovation Mold & Design asked its customers what was needed to help them be more competitive in today’s demanding manufacturing environment, the typical response was: help us manufacture the highest quality parts in the shortest possible lead times and reduce the investment.
What might seem like a minor change to the OEM might in actuality be a major change to the moldmaker, resulting in a major cost increase. Depending on what stage the mold build is in, the change could result either no cost increase, minor cost increase or a big cost increase. That’s why it’s increasingly critical to have the CAD file as accurate and close to the desired end-
Up to the challenge, Innovation proposed a simple and effective approach to the typical process of quoting a job. Dan Fairbanks, President of Innovation Mold, says, “A large percentage of our customers are OEMs. When our
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product as possible.
much more careful consideration.”
“Small changes to a part design can result in a long list of adverse effects on the mold design and the processing of that part,” says Hans Noack, mold designer for Matrix Tooling Inc. (Wood Dale, IL) “Features that have been added, adjusted, or even eliminated may affect cooling and ejection, which will then alter the cycle time.”
Changes that require re-cutting steel or re-burning electrodes often mean major delays, and the moldmaker is then put on hold until the new changes can be approved by the customer. When the customers drag their feet in approving part designs, mold designs, or changes to part or mold design, they risk delaying delivery of the mold and increasing the price.
Missed dimensional numbers in file translations from one type of CAD system to another, continue to plague moldmakers in spite of the many improvements that have been made by CAD software makers. If the mold company works in 3D, you can see a “virtual model” of the part before steel is cut, and that is a prime opportunity to make any changes that might be required.
Many years ago, when 16-20 week lead times were common, shops had time to allow for changes. No one was in a big hurry. In today’s fast time-to-market demands from OEMs, and lead time averaging eight weeks or less for straight-forward, lower-cavitation molds, changes may come too late in the game. Highspeed machining means that steel gets cut in a matter of hours rather than days, as it used to be two decades ago. So, OEMs need to keep that in mind when moving forward on a new program.
Engineering Change Orders (ECOs) can create problems. Moldmaking industry standards generally dictate that when a customer calls with an ECO to the part design, the moldmaker tells the customer by phone personally or by e-mail (which creates a paper trail), that the change might affect the lead time and/or price of the mold. Both of these can be costly, depending on the changes made.
In some cases, the molder or the OEM might change the way it processes or handles the manufacturing process, and that might require an engineering change. Noack also notes that OEMs need to consider how the part will be used. “In some cases robotics and other automation will need to be adjusted in production to compensate for a design change.”
After a review by the mold designer of the change requested, the mold company can then make the necessary changes to the schedule and/or the price, and notify the OEM or the molding company of those changes in writing. Everything should be in writing! Don’t leave anything to verbal instruction or information, because if it isn’t written down and confirmed, it’s like it never happened. This practice stems from customers who make major changes to a part design that result in changes to the mold that in turn result in additional costs and a longer lead time, yet expect to hold the mold manufacturer to the original price and lead time. Change is just what it indicates: CHANGE. In many cases nearly everything changes when one thing changes.
Jim Ziegenhorn, Matrix Tooling’s CAM programmer, provides an example of a picture frame part. “The design will reflect all the cooling, ejection, strength and support issues. Then comes a request for a simple connecting span of plastic between the outside portions of the frame, which seems simple enough at first, but you have to consider that you may not be able to add adequate ejection due to cooling lines being in the way,” Ziegenhorn. “If you remove some of the cooling to add proper ejection then the cycle time will be affected. If the cooling becomes unevenly distributed, you could have issues with part warpage. Support may also be affected due to the additional ejection which can have an adverse effect on strength.”
If an OEM begins to make a lot of changes, the moldmaker might be forced to put the project on hold until all the changes are worked through and finalized on the part design before actually cutting steel. Once the mold manufacturer begins cutting steel, any changes to the part’s design can become more costly, depending on how far along the moldmaker has gotten in the build process.
Changes during the mold build or changes after the mold build to accommodate different processing parameters or the use of automation, can often be costly. And, as Ziegenhorn points out, it’s often a series of affects when one, seemingly simple change is made. “Some of what seems to be the most minor modifications can adversely affect the whole process of the tool build and part processing.”
“Tool designs are always based on the final geometry of any given part. Prior to manufacturing, all designs are usually be modified with relative ease,” explains Noack. “Design changes after the manufacturing process require
Thanks to Matrix Tooling Inc. (www.matrixtooling.com)
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thing an OEM purchasing agent or engineer can do is to educate themselves about these various types of molds.
for its input into this article. If you have questions for moldmakers, see www.amba.org and click on “Ask a Moldmaker”. By: Clare Goldsberry
1) Conventional or standard mold: A standard mold with an ejector-plate assembly is generally used when parting line runner are acceptable, and ejector pins, sleeves, or blades are adequate to remove the molded parts from the mold. A standard mold is sometimes referred to as a two-plate mold and consists of a cavity and a core side.
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Selecting the Optimum Type of Mold for Your Part
2) Slide-core Mold Base: When an undercut or coring feature is required that cannot be formed and ejected through a standard mold opening, a slide-core mold base is generally used. The slide core is used to form the feature and is withdrawn prior to ejection of the part. When slides are present, the mold closes, the slides come into place, the plastic is shot into the mold, the slides pull out, and the mold opens, allowing for easy removal of the part. This mold is good for parts with complex features.
When OEMs consider a new plastic product or component part that requires a mold, one of the first things they think is “how much will this mold cost?” Mold cost is not the first consideration that a company should make, but what type of mold will reduce your overall cost to manufacture while improving quality. Part cost will vary depending on the type of mold that you choose. And the type of mold that you choose is based on a number of factors:
3) Stripper-plate mold: When ejector pins or blades are inadequate or objectionable in removing parts from a mold, a stripper-plate mold is generally used. Caps and closures with internal threads are examples of parts that might be molded in this way.
·Number of parts required annually - this figure should be an accurate figure, not something pulled out of the air or a guess. If you need 3 million parts annually, then you’ll need a mold capable of running 3 million parts per year comfortably so you can meet your manufacturing schedule without downtime.
4) Three-plate mold: When placing a gate at the side or edge of a part is objectionable because is could cause fill problems, a three-plate mold permits a central fill point that allows for uniform filling without part-weakening weld lines.
·Will a secondary operation be required for the part? If so, there are various technologies that can reduce costs such as inline operations or even in-mold technology that can significantly reduce cycle time and manual handling of parts that will improve quality.
5) Thread-forming (unscrewing) mold with a hot manifold: When a part requires internal threads and cannot be ejected by a stripper-plate mold without damaging the threads, a thread-forming mold generally is used. The hot manifold is a heating and distribution system for the resin, used for many types of molds; the system feeds from the molding machine’s injection nozzle and carries the melted plastic directly to each cavity or to a secondary runner system. Thread-forming molds are used in producing plastic nuts, bolts, certain gears and caps and closures for the food and beverage industry. Internal threads can sometimes be stripped or molded with collapsible cores, as in soft-drink and coffee closures, respectively.
·Material selection is also key to the type of mold you will need. Certain filled engineering thermoplastics cause more wear and tear on the mold, so you will want a hardened steel mold for many applications in which glass filled or other filled materials are required. · Part cost is also important. Do you know your target part cost? If so, talk to your mold supplier about that cost because he/she can help you get to that target by designing the appropriate mold for the part. · Design of the part. All plastic parts must be designed for manufacturability. While a part design might look good on paper, it might not be manufacturable in its current iteration. Or it might be manufacturable but at a very high cost in both mold and piece-part price.
6) Family mold: Multiple components of a product, all made of the same resin, can be molded in a family mold cavity. A good example of a family mold’s use is for a plastic model car or airplane in which parts of various sizes and shapes come still attached to one runner. But
There are many different types of molds and the best
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don’t let that fool you when it comes to price or complexity. Family molds are extremely complex and must be carefully designed in order for them to be balanced and permit optimum molding. The use of sequential gaging technology for timing gate openings and closings, which results in optimum parts from a family mold, makes the process easier. However, Anne Bernhardt, president of Plastics & Computers Inc., notes that “a family mold increases the complexity of the process and of the mold, requiring a more precise operation all the way around.”
While you don’t need to know all the details about all the types of molds that are available, you should be familiar with a few of the options before you send out a request for quote. This ensures that you can get the best mold for the money, one that will meet your needs and provide optimum manufacturing in a cost-effective manner. The more you know about your own requirements, the better your mold supplier can assist you with making the right decision. For more information, order your copy of Purchasing Injection Molds: a buyer’s guide, by Clare Goldsberry. Available from www.amba.org
7) Stack mold: Essentially, a stack mold is two molds stacked back-to-back that share a common plate. A stack mold doubles the cavitations without the need to increase press size, and are typically used for flat parts such as food container lids, coffee-can lids or thin-walled shallow food containers. Stack molds have gained in popularity over the past decade, particularly in the packaging industry as the volumes tend to be high and stack molds provide high-productivity and efficiencies, often without adding molding equipment or production space.
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Does Offshoring Molds Still Make Sense? U.S. moldmakers have become more competitive in price and leadtime over the past decade than ever before. While U.S. mold manufacturers are not afraid of competition, they continue to fight for "fair" trade, not just "free" trade. They know that when bidding on a job against China , they can come close to the Chinese price thanks to technologies such as 3D CAD modeling, HighSpeed Machining (HSM), and more efficient ways of mold build. Still, they are being asked to find a China source. Recently, a mold manufacturer told me that a major appliance maker was set to let $26 million in tooling over the next year, and announced that as proof that they were promoting manufacturing in the USA . The catch was that while the jobs were to be released to U.S. mold companies, they required 70% of that work to be sub-let to Chinese mold shops -- regardless of whether or not the U.S. mold maker could meet the Chinese price.
8) Rotating Stack mold: Rotating stack molds or “Cube” molds have also come onto the scene over the past decade. Another name, Spin Stack(tm) technology, requires a license. This is generally a multi-cavity mold which combines a number of processing technologies including in-mold labeling, in-mold painting, in-mold assembly, etc. through the use of a “cube” mold. The first station is where the initial plastic substrate is shot into the cavities, then the mold rotates 90 degrees, and perhaps another type of plastic such as a thermoplastic elastomer is shot over that. Then another 90 degree rotation takes it to a station where another operation such as assembly is performed and then another 90 degrees where the part is ejected. While the molds are not cheap, much can be saved in secondary operations by doing several steps in the mold. 9) Two-component molds: For molding parts that have two different materials (a thermoplastic substrate with an overmolded thermoplastic elastomer, for example) or two different colors (such as a red and orange tail light assembly), a two-component or “two-shot” mold is idea. Doing both materials or both colors in one mold saves time in having to remove the first component from the mold, and placing it into a second mold for the second shot. Tooth-brushes are a good example of a hard plastic substrate with a thermoplastic elastomer grip overmolded onto it. Generally, two different material shrinkages must be considered and good bonding between the two materials must be ensured.
The American Mold Builders Association is engaged in an effort to educate OEMs about the True Cost of their molds that are let to Chinese mold builders, so that when mandates come from upper management that a percentage of mold programs MUST be let to Chinese shops, engineers and purchasing managers have the knowledge necessary to show upper management the benefits of staying in the USA, particularly for molds that will be run in facilities in the USA. Recently, Farouk Shami, CEO of Farouk Systems Inc., Houston, Texas , announced that he is moving all of his
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http://www.scmr.com/article/329491Does_offshoring_still_make_sense_.php
manufacturing from China to Houston , where the company's headquarters are. He has enlisted two molders, so far, to mold the parts for his hair blow dryers and hair irons, and other hair care products containers, and is looking for U.S. moldmakers with to partner. His main reason for moving manufacturing from China is the tremendous costs associated with piracy and counterfeiting. He was spending upwards of $500,000 a month to combat counterfeiting and in refunding money to customers who bought his products which then failed to perform, as counterfeit products often do.
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Typical Mold Materials: Which One is Right for the Mold you Require? There are many types and grades of mold materials to choose from when specifying your mold. So how do you know which is best? Generally, your mold manufacturer can help you make that determination when you sit down to discuss those criteria that will impact which mold material is suitable for your requirements.
Many other companies, major firms such as Emerson Electric, are moving manufacturing from Asia back to North America . Many are choosing to manufacture in Mexico , our neighbor to the south and NAFTA partner, with the molds being made in the U.S. Many AMBA member companies build complex, highly technical molds that provide long life, high productivity and efficiency, and perform over the long term as expected. And U.S. mold manufacturers offer support after the sale, without the expense of shipping the molds across an ocean!
Some of the considerations that are critical to the choice of mold material are: * Program life - Do you expect the program for the particular components to last one year? Five years? or longer? If you anticipate a long program life, then you need a mold that will be extremely durable to provide the most trouble-free molding operation.
However, if you have molds built in China that need engineering changes, rework, repair or rebuild -- as many do once they hit U.S. shores, there are many AMBA member companies that specialize full time in these projects for OEMs that buy molds from China.
* Plastic material - What type of material will be used to mold the parts? This also weighs heavily on the type of mold material you will choose. For example, if the resin is abrasive, i.e. is a glass-filled material, metal-filled, etc., a softer mold material will mean greater wear on the cores and cavities, more maintenance and shorter life of the mold. Unfilled commodity-grade materials such as polypropylene, low-density polyethylene, and even unfilled engineering-grade materials such as polycarbonate or ABS, generally are okay for a softer grade of mold material.
The cost of shipping, engineering time away from the office to oversee mold builds in Asia that require expensive air fares, hotel bills, and other expenses are drastically reduced or in some cases eliminated with building molds in the U.S. And, U.S. mold manufacturers can, in most instances, come within 10% 20% of the quoted prices on molds from China . Thus, there is no real benefit to building molds in China if those molds are to be run in the USA .
* Number of parts required - How many parts will you require per month? per year? If that number is low – 100,000 parts or less annually – then you can probably get away with a softer mold material. However, if you require five million parts annually, you might want to look at hardened tool steels to meet these requirements.
Below is a link to an article for you to read that we think addresses this issue quite well, and hope you will find it informative. If you want to understand your costs to buying offshore vs. the US, please write to us and request, "Knowing the True Costs of Your Molds", a brochure with a worksheet to help you determine whether or not it makes sense for you to build offshore. If you decide that it doesn't make sense for you, go online to www.amba.org, and look at our list of nearly 300 mold manufacturers. There is quality-oriented mold manufacturer near you, right in your own backyard. Then you can proudly say, "Made in the USA ."
There are a number of different types of mold materials. A) Aluminum - This is becoming an increasingly popular material for injection molds, primarily because many of the grades of aluminum can provide a cost-effective alternative to mold soft mold steels. In today’s manufacturing world, many programs are seeing shorter lifespans as products evolve to meet changing consumer
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contacts with all the mold steel and aluminum suppliers, and can provide you with spec sheets and other information on the suitability of the various materials to your mold and molded parts requirements.
needs, so that a program that might have lasted five years a decade ago only last a year now. That means fewer parts that need to be molded and an aluminum mold will work just fine. Aluminum is easy to machine, so lead times can be reduced and overall cost-savings realized. Aluminum is also typically used for thermoform molds and blow molds. Typically, aluminum isn’t used where tough, abrasive resins are required for the parts.
Additional Resource: Moldmaking Technology Magazine - www.moldmakingtechnology.com/articles/080001.html Want to extend the life of your mold? Read Clare Goldsberry’s article in Injection Molding Magazine on Using Plating to Extend the Life of Your Mold. June 3, 2009
B) P-20 - This is a pre-hardened chrome-moly tool steel made specifically for machined cavities. Usually no heat treating is required. Many times, P-20 will be chosen as a step above aluminum for longer life.
www.plasticstoday.com/imm/articles/gaining-edgeplating-longer-mold-life
C) H-13 - This is a chromium-based mold steel designed for increased production and longer mold life. It is thermal shock and fatigue resistant, and offers superior machinability and polishability.
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D) S-7 - This is a versatile grade recommended for applications demanding high degrees of toughness and moderate wear resistance.
What Constitutes a Good, HighProduction Mold?
E) Stainless Steel - This steel is used for extremely high part volumes and provides high polishability for molding aesthetically sensitive parts, particularly medical-grade components, and products for the cosmetics industry. Bohler-Uddeholm provides a prehardened 400 series Stainless Steel that offers many benefits (www.bucorp.com/files/MMT_Bohler_M303extra_featu re_article.pdf).
Building high production, high cavitation molds requires a mold manufacturer whose expertise is in this arena. While every mold the OEM builds needs to be a wellbuilt mold, made to specifications and able to make a conforming part, building molds for high production requires special diligence and careful choice of mold manufacturer. Early involvement with the mold manufacturer is always key, and you need to crunch the numbers to make sure that the mold you buy is really the one you need. Often, OEMs will estimate a greater number of parts required than they actually need when they start production. It’s not uncommon for an OEM to ask a mold manufacturer to quote a mold that will make 500,000 parts per month, only to find out that the product isn’t taking off as marketing anticipated or the ramp-up was slower to happen.
Some mold steel companies offer their own “brands” of these various mold materials, such as International Mold Steel. That company supplies a variety of mold materials such as Porcerax II, a sintered porous metal with porosity in the range of 20-30% by volume. Using this in appropriate areas eliminates gas build-up, reduces injection pressure, lowers cycle times, gloss levels and substantially reduces scrap and reject rates, according to the company.
In estimating the number of parts high-production molds make, there is the actual part production in one hour vs. part production in one hour at 85% efficiency. For a part running at a five-second cycle in a 32-cavity mold, the actual number of parts is 23,040. For that same part running at 85% efficiency, you’ll get 19,584 parts per hour. That translates to 171,555,840 parts in one year. [See Appendix B of this Tip Guide]
International Mold Steel also provides NAK 55 and a NAK 80, both are 40 HRC pre-hardened to 38-42 HRC and machine fast, don’t need stress relieving generally, and are highly weldable. The company’s PX5 is a modified P-20. As is typical when processing plastic parts – no matter what the process, be it injection molding, thermoforming, or blow molding – there are many variables involved that impact the choice of mold material. The best way to make an optimum selection is to consult your mold manufacturer, who has excellent
Many high-cavitation molds can be seen running with several cavities blocked off because those cavities were not making conforming parts. For molders, whether
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custom molders or OEMs’ in-house molding operations, sometimes it’s easier to block off the non-conforming cavity and keep running that to stop the press, take the mold out and fix it. You don’t get the best productivity out of a high-cavitation mold – say 32 cavities – if only half of them are running.
Volume is another consideration. Mold buyers with large-volume requirements, such as several million parts annually, often prefer to buy a large multicavity mold – one with 32, 64, or even more. (Remember, the number of cavities must be balanced – 2, 4, 8, 16, 32 or more. This is sometimes referred to as the “power of 2” meaning 2 to the second power equals 4, 2 to the third power equals eight, and so on.)
Part cost and productivity go hand-in-hand, but realize that only a well-built, precision mold will provide you with the productivity required to reduce cycle time and thus part costs. Those considerations need to be made up front, with a mold manufacturer that is qualified to build high-production molds that run in a high-volume setting.
Small components like disposable medical parts or caps for soda bottles, or milk or water jugs, and other closures for food containers, are often molded in large, multicavity molds that require presses with larger tonnage. Some of these molds are more than 200 cavities! That’s a lot of parts, but then companies that produce millions of bottles annually need a lot of bottle caps!
Excerpted from Purchasing Injection Molds: a buyer’s guid, by Clare Goldsberry. For more information,or to order your copy, available from www.amba.org. ■■■■■■■■■■■■■■■
Some mold buyers with high-volume requirements prefer several smaller, multicavity molds – perhaps four 8cavity molds that run in a 150-ton press vs. one 32-cavity mold that runs in a 300-ton press. The strategy of using four 8-cavity molds means that the molds have a smaller footprint, and run in smaller presses that cost less to operate, and can often reduce overall costs to manufacture. Although the piece part price is exponentially less with a higher cavitation mold, the fact that the mold must run in a larger press that costs more to operate often offsets any real savings in piece part price. Smaller molds are easier to move in and out of the press, and easier to maintain.
How Big, How Small, How Many? Determining the Number of Cavities in a Mold Determining the number of cavities in your mold requires more than just an educated guess. It’s critical to the productivity and efficiency of the mold, and to your own inventory needs to have the appropriate number of cavities.
Some molding personnel point out that rarely do you see a 64-cavity mold with all 64 cavities running. With a large mold, should a cavity begin making a nonconforming part, maintenance will typically block off that cavity until the mold can be taken out for repair. It’s not unusual to see a high-cavitation mold with a dozen cavities blocked off because the mold needs to run 24 hours a day, seven days a week until they can get a break in the production cycle. From a production standpoint, this is neither efficient nor productive or cost effective.
The number of cavities in a mold is a function of the number of parts required annually. A mold with too few cavities won’t be able to meet your requirements – or will be able to meet them only if the press runs 24 hours a day, seven days a week, 52 weeks a year. Since that is nearly impossible and there is always some downtime to consider for mold maintenance, repairs, or other unexpected interruptions, estimating the number of cavities is critical to meeting your demand for parts. Typically, say those in the industry, mold buyers don’t define their targets with respect to manufacturing goals. Buyers should ask themselves, “Why do I want a 16cavity mold vs. a four-cavity mold?” And the answer should be a better one than “Because it’s cheaper.” The more cavities you have, the larger the mold must be to accommodate them. With a large part, more than one cavity means a mold with a footprint of several square feet, and it might be better to choose a one-cavity mold. Smaller parts are more easily accommodated in a multicavity mold.
In making a decision as to size and number of cavities, the prudent approach is to work with a moldmaker to evaluate the number of parts required weighed against the cost-effectiveness of large vs. small multicavity molds. Excerpted from Clare Goldsberry’s Purchasing Injection Molds: A buyer’s guide.
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5. Have the moldmaker establish a production timetable that allows reasonable time for bench testing prior to delivery. All too often a mold is delivered to meet a production deadline without being fine-tuned in a lab situation. Your moldmaker should have the opportunity to run sample parts at his facility. If there is a problem he can correct it before delivery.
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Ten Pointers for Better Mold Production Although the criteria and the technology used to produce molds have changed dramatically in recent years, the basic rules for developing a mold that meets the original design criteria, and functions effectively, have not changed at all. These tips are based on more than 30 years experience in the field of mold and die manufacturing. Many of these tips talk about communication. As any moldmaker will tell you, all too often there is incomplete information available at the onset of a program. This is like having only half the map; the chances of getting to the final destination on time are very slim.
6. Set up a weekly progress report call/e-mail with your sales representative during the manufacturing process. Sales reps are busy people. It helps to establish a regular contact point to ensure the project is on schedule and on budget. It doesn’t matter what size the project is, it’s worth a weekly call to eliminate assumptions. 7. Ask the moldmaker for clear guidelines on how to maintain the mold once it is installed. Molds may be operated in less than ideal conditions. Poor storage of materials, mold cleaning on an irregular basis, bad press maintenance and ill-trained operators can all contribute to poor mold performance. Your moldmaker should include a set of instructions for care and maintenance based on the specifications for usage.
1. Design with specified cost and time criteria. The old rule of “good, fast and cheap” still applies. There always seems to be time for rework or adjustment after meeting that ultra short deadline, but it is better to allow reasonable time in the design stage for review and correction.
8. Have a field sales representative from the mold shop present during initial start-up and try-out. A buy-off is very important. Many molds and dies have sustained serious damage and require immediate repairs due to poor installation. Having a technical representative on site the first time the mold or die is installed is good insurance.
2. Make sure your design specifications can be produced using existing technology. Programs like Solidworks and the availability of rapid prototyping can provide early insight into potential problems that might occur before metal gets cut. Provide the engineering group with full specifications, do not leave anything out. If something is left out here it will cost time and money to fix later in the process.
9. Remember that the design and manufacture of a mold or die is a collaborative effort. Mold and die making is a combination of science and art. Building a tool that will work 24/7 if required, demands careful planning and checking at every phase of production. Allow the time and expense for your staff to visit the mold shop facility during production.
3. Share your company’s design philosophy with your moldmaker and allow the moldmaker’s design team the opportunity to contribute. Many companies design new molds and dies based on their current inventory and their operating environment. It may be possible to speed up production with some very simple modifications to a design. Invite your moldmaker to make suggestions that can enhance moldability.
10. Don’t cut corners! Giving the job to the lowest bidder might not make sense. There is a reasonable price to pay for a mold or die. If your budget is too low the chances are that you will be rebuilding or repairing the tool within a fairly short period. Trying to squeeze the last dollar out of a moldmaker’s estimate can end up doubling the cost of the project. After all, price is what you pay for a mold. Cost is what you continue to pay for a mold that was not built correctly in the first place.
4. Set clear guidelines on required minimum tool life and capacity before manufacturing starts. A clear definition of the expected performance and service requirements on a mold or die can help to save money upfront. If your product is likely to be modified or replaced in a relatively short period of time the moldmaker’s engineering group can design accordingly.
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By: Kevin Hartsoe, President, NEU Dynamics Corp., www.neudynamics.co, Contact the author at
[email protected].
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U.S. mold builders use SPI mold standards to ensure high-quality molds.
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U.S. mold builders provide collaborative product development
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U.S. mold builders building in the US means you have recourse if you have a problem. U.S. mold builders use quality mold steels and mold components to ensure long-lasting production. The local mold builder knows that the tools may be seen again later for maintenance or repairs so the local toolmaker’s approach is going to include the use of quality steels and components, and he’s going to make the tools easy to service and not take any short cuts that will lead to dreaded ‘no charge fixes’.
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Advantages of U.S. Molds •
U.S. mold builders won't copy your intellectual property -- your valuable proprietary information is safe. A local mold builder overwhelmingly holds the advantage of the trust factor.
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U.S. mold builders stand behind their work -- if you have a problem with your mold, they will make it right!
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U.S. mold builders support their customers in long-term relationships -- you have a friend in the American Mold Builders Association!
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Typical lead time for the freight is 3 to 4 weeks for off-shore vs. 3 to 5 days in the U.S. Have you factored in the cost and lead time to ship a large mold from Asia to the U.S.? The cost of ECOs or rework that a U.S. moldmaker will have to do? (You won’t be shipping a mold back and forth across the Pacific Ocean for rework and ECOs!) And the cost of the mold’s productivity and efficiency, and maintenance over the life of the program.
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Buying products made in American factories by American workers keeps jobs in the US.
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Over the life of the mold, the value of that tooling investment is enhanced through a relationship with the U.S. mold builder. Good communication during the program launch, part revs to be in sync with the mold design through collaborative engineering, a familiarity with the mold buyer’s past preferences, assistance during startup and service after startup: all reasons to dismiss the lure of seemingly cheap overseas tooling.
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It’s been said by a U.S. mold buyer, “The price difference for equivalent tools is getting closer” between U.S. mold builders and overseas mold builders. U.S. mold builders have adopted lean practices and process optimization including high-speed machining technology and robotic work cells. Reducing time and labor has helped reduce costs. Today’s pricing of U.S. molds may be lower than you think!
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U.S. mold builders speak your language -nothing gets lost in the translation. What is your time worth? Communication can be a challenge when you’re working with off-shore suppliers.
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U.S. mold builders are right in your backyard -you can visit them quickly and less expensively than you can if you had to fly to Shanghai or Mumbai.
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5. Strength of supports
4. Strength of materials
3. Servicing of hot runners
2. Runner Systems
1. Concept & Design
Subject
Little if any thought has been given to the mold, except getting the shape of the product right, at the lowest possible mold cost.
Mold (B)
Cavities and cores are often not strong enough and expand or deflect when subjected to high injection pressures. The mold plates are thin, just strong enough to hold the components in position.
Appendix A
Support plates are too thin and supports under the Support plates are adequately heavy and sufficient supports cavities and cores are too small and often too far are provided under the cavities and cores to ensure minimum apart, resulting in excessive deflection of these plates, misalignment between cavities and cores and deflection of the plates under load by clamping and during causing excessive wear in the alignment features. injection, thus guaranteeing quality products.
The strength of materials used in the mold is properly engineered. This applies typically to the strength of cavities and cores to contain the high injection pressures and the size of mold plates to support both cavities and cores.
In hot runner molds, access to the hot runner system for minor servicing (changing heater bands or nozzle tips, etc.) is The mold must be removed from the machine for any service to the hot runners. possible right in the machine, without removing the mold.
As long as the mold can produce the desired Much thought is given to decide on the most suitable runner product, even only for a short length of time, it is system, the gating, cooling, and ejection of the products. considered acceptable.
Conceived from start with high productivity and lowest cost product in mind. Much time is spent on the mold concept before starting the actual design, or beginning to cut steel.
Mold (A)
The difference between a well-designed and solidly built mold, (A) planned to produce reliably good quality products at the lowest cost, and a low-cost mold (B) intended for the same product, can usually be seen right from the start, by visually comparing the two molds, and becomes obvious after operating the mold for a relatively short time. * (excerpted from "Selecting Injection Molds, By Herbert Rees and Bruce Catoen.)
What Characterizes a Good, High-production Mold?
9. Tapers
8. Mold Alignment
7. Mold hardware
6. Mold steel selection
Subject
Mold (B)
Alignment feature (leader pins, tapers). Long, especially unsupported leader pins are heavy to ensure minimum deflection. They are long enough to protect the exposed cores from damage. Tapers for alignment are sized proportional to the length of the core.
Alignment tapers are properly engineered, with specified amounts of preload, to ensure holding the matching parts in alignment securely.
Leader pins are often too short and too slender, just long enough to engage to LP bushings. They deflect easily and do not guarantee proper alignment of the mold halves. Tapers are usually too short, wear soon, and do not hold the cores aligned with the cavities.
Careful consideration is given to select the best quality of (purchased) mold components to ensure trouble-free operation.
Appendix A
Tapers are matched without proper preload, and therefore do not provide alignment. This can be easily seen just after a few days of operation when both matching surfaces are seen dirty or corroded. Properly preloaded tapers are always shiny.
Leader pins are often too short and too slender, just long enough to engage to LP bushings. They deflect easily and do not ensure proper alignment of the mold halves. Tapers are usually too short, wear soon, and do not hold the cores aligned with the cavities.
Mold steel selection is appropriate for the expected life and performance of the mold and often, the best quality steels and other materials are selected, without too much concern Any grade steel is used for the plates and cost of about the added cost. (After all, with large production runs, materials and mold components is a serious the additional cost per molded piece is infinitesimally small). consideration.
Mold (A)
The difference between a well-designed and solidly built mold, (A) planned to produce reliably good quality products at the lowest cost, and a low-cost mold (B) intended for the same product, can usually be seen right from the start, by visually comparing the two molds, and becomes obvious after operating the mold for a relatively short time. * (excerpted from "Selecting Injection Molds, By Herbert Rees and Bruce Catoen.)
What Characterizes a Good, High-production Mold?
13. Testing of mold
12. Mold mounting
11. Moving plates
10. Productivity
Subject
Mold (B) Cooling channels are frequently placed almost as an afterthought, rather then planned from the beginning, and often omit difficult-to-cool hot spots. They are then connected outside the plates and often require an excessive number of hoses to be connected; they are making setup and servicing more difficult and invite errors.
Mounting the mold to the machine is considered from the beginning and the most suitable mounting methods are provided. The mold is thoroughly tested at the mold maker, not just for product sizes and fits but also for productivity of the mold, before delivery.
Appendix A
The mold is only tested to check the sizes of the products, and then shipped.
Usually, only mounting ledges are provided for the use of rather unsafe mold clamps to hold the mold in position.
Moving plates, such as ejector plates, are properly Moving plates, such as ejector plates, are properly guided guided and supported to minimize wear of delicate and supported to minimize wear of delicate pins, etc. Proper, pins, etc. Lubrication of wear points is left to the often automatic, lubrication of wear points is provided. operators of the machine.
Cooling channels are carefully planned for optimal size and location to provide maximum cooling efficiency and ensure highest productivity. Cross drilling of the plates (which is possible because they are thick enough) simplifies the installation of the mold and improves the accessibility of the mold for servicing during startup.
Mold (A)
The difference between a well-designed and solidly built mold, (A) planned to produce reliably good quality products at the lowest cost, and a low-cost mold (B) intended for the same product, can usually be seen right from the start, by visually comparing the two molds, and becomes obvious after operating the mold for a relatively short time. * (excerpted from "Selecting Injection Molds, By Herbert Rees and Bruce Catoen.)
What Characterizes a Good, High-production Mold?
16. Productivity
15. Mold manual
14. Cost of extras
Subject
Mold (B)
There is usually no such mold manual supplied.
Appendix A
With every of the frequent breakdowns the molder loses money, and any savings on the mold are soon surpassed by the costs of downtime & repairs. Low The molder smiles when he sees the mold producing large productivity & higher costs per unit produced will cost quantities of good quality products, without breakdowns. The the molder much more than was saved in the first higher cost is soon forgotten. place, particularly with large production runs.
The customer is supplied with a "Mold Manual", which documents all that is to be known about the mold and its accessories and vendor's products. It includes mold drawings, test reports, safety tips, and mold maintenance and trouble shooting instructions.
Cost of extras are included in the mold price. These extras consist of all necessary hardware to store, install, start up and run the mold. To have these costs included makes it possible to compare fairly all potential vendors. The following list shows some but not necessarily all of these items: (Note that when requesting a quotation, it is good practice to request that any such foreseen item or feature is included in Mold making is a very competitive business, and by the quotation.) 1.) Materials used for construction, 2.) Coatings and finishing including plating (molding surfaces), omitting to commit oneself on expected productivity 3.) Pipe fittings and hoses, 4.) Electrical cables, 5.) Mold feet, and to consider necessary extras, the quoted mold latches, and lift bars, 6.) Suggested spare parts, 7.) Crating price could become lower, thus more interesting to and preparation for shipping, 8.) Cost of re-cuts, 9.) Cost of the unsuspecting buyer, who will later be faced with many additional expenses, or lack of productivity of re-tests, 10.) Guarantees on product size, 11.) Expected productivity, 12.) Payment terms and conditions, 13.) Extent the mold. The difference could be as much as 20% of the mold price. of warranty.
Mold (A)
The difference between a well-designed and solidly built mold, (A) planned to produce reliably good quality products at the lowest cost, and a low-cost mold (B) intended for the same product, can usually be seen right from the start, by visually comparing the two molds, and becomes obvious after operating the mold for a relatively short time. * (excerpted from "Selecting Injection Molds, By Herbert Rees and Bruce Catoen.)
What Characterizes a Good, High-production Mold?
$ ________________________________________________
__________________________________________
TOTAL COST OF PRODUCT: $ ______________________________________
3. Freight, Warehouse, Logistics costs: $ _____________________________
2. Life-time cost of parts: $____________________________________ (price * annual volume * years)
1. Total cost of Mold program: $_____________________________________ (total all items above)
$ _________________________________________
$ ________________________________________________
Maintenance costs:
Shipping costs:
Cycle time:
Replacement Tooling Cost: $ ________________________________________
Mold Life Guarantee ____________________Years ________________cycles
Lost Production: $ ________________________________________________ (due to ECOs/Rework/slow cycle time)
$ ________________________________________________
$ _________________________________________
Mold tryout:
ECOs/Rework:
$ _________________________________________
Brokers fees:
Consultants fees: $ ________________________________________________
Shipping prints:
$ _________________________________________
$ ________________________________________________
Miscellaneous:
Phone/Fax:
$ ________________________________________________
Air fare: $ ________________________________________________ Hotel: $ _________________________________________ Food: $ _________________________________________
$ _________________________________________
Transportation:
Travel:
Price of mold
$ _________________________________________
$ ________________________________________________
$ _________________________________________
$ ________________________________________________
$ ________________________________________________
$ _________________________________________
$ _________________________________________
__________________________________________
TOTAL COST OF PRODUCT: $ ______________________________________
3. Freight, Warehouse, Logistics costs: $ _____________________________
2. Life-time cost of parts: $____________________________________ (price * annual volume * years)
1. Total cost of Mold program: $_____________________________________ (total all items above)
$ _________________________________________
$ ________________________________________________ Maintenance costs:
Shipping costs:
Cycle time:
Replacement Tooling Cost: $ ________________________________________
Mold Life Guarantee ____________________Years ________________cycles
Lost Production: $ ________________________________________________ (due to ECOs/Rework/slow cycle time)
ECOs/Rework:
Mold tryout:
Brokers fees:
Consultants fees: $ ________________________________________________
Shipping prints:
Phone/Fax:
Miscellaneous:
$ ________________________________________________
Air fare: $ ________________________________________________ Hotel: $ _________________________________________ Food: $ _________________________________________ Transportation:
Travel:
Price of mold
OFFSHORE MOLDMAKING SOURCE
Finding the Total Cost of Your Mold
U.S. MOLDMAKING SOURCE
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