Robotic Operations Instruction
Part 1 (General Robots) A. Intro to Operations B. Setting Up My Robot 1. Program Allotting 2. Proper Staging 3. Proper Tools C. Running My Robot 1. Loading Parts 2. Buttons Galore 3. Fixture Quality D. Correcting Run Errors
Part 2 (OTC) E. Intro to Programming F. Programmable Points 1. Position Points
- “P” Points - “L” Points - “C” Points - “HP” Points 2. Non-Position Points/Commands - “T” Points G. Welding Commands 1. Intro to Welding Commands 2. “AS” – Arc Start - Volts - Amps / IPM (Wire) - Torch Speed 3. “AE” – Arc End - Volts - Amps / IPM (Wire) - Crater Time - Post Flow 4. “WS” – Weave Start - Amplitude (Y1, Y2) - Frequency - ¼ , Center, ¾ Stops 5. “WE” – Weave End
PART 1 (General Robots) Intro to Operations
Welcome to the world of Robotic Welding. Robots have been used in manufacturing for years, and are the future of most production based companies. The Th e task of running a robot, while it may seem simple, can be anything but, at times. A lot of the fundamentals from hand welding can easily be applied to running a robot. Similarities include, blueprint reading, staging your area, fixturing, qualit y, and safety to name a few. fe w. We will go into more details soon. While you’re reading this, take everything in, some of it may be out of understanding u nderstanding at the moment, but the goal of this article is to be used for training first, referencing second. Setting up My Robot
The easiest mistake an operator can make mak e is poorly setting up his robot. A clean setup, with enough room to work, everything to reach can at times be a task, properly written program, good component parts, and the traveler at his station. Some of these are easier to control then others, Obviously as an operator, your not actually writing the program, however you can still inform your superiors of any concerns you have with the program, and they will be happy to help get it fix. Experience, Knowledge, and Communication are the three key factors to ensuring your area is able to run at max efficiency. Proper Program Allotted Let’s delve deeper into what it takes to make sure you are in a situation to do your best, the last thing a
group leader wants to do, is put p ut any operator in a position to fail. We are here to do everything ever ything we can to ensure you have the proper training, tools, and help you need to perform your job. The first thing any operator should check for is to ensure the correct program is allotted into the robot. “Allotted” is a term we u se to say “When I push the start button, I want to run this program.” Each robot is different different in this task; your group leader will provide instruction on how to check this. It should be mentioned that a majority of the time, the group leader will have already done this for you. Proper Staging
Staging your area is the best way wa y to set yourself up for success. There are three th ree golden rules to follow when staging your area. 1) The fewer amount of steps you take, the faster you will be. 5 steps is always faster then 10 2) Assembly lines work for all aspects; all your components should be in one place, then your work table, followed by your finished part skid. This prevent confusion and lost time trying to remember your steps/sequence 3) Make sure you have enough room to work comfortably, if you cram everything together, your not going to make any progress tripping over everything. Find the happy medium of not walking too far, but having room to perform your job. Each person will be different. Proper Tools Don’t bring a knife to a gun g un fight. The same applies to working in a factory. You wouldn’t use a screw driver to hammer in a nail. Why Wh y use a small angle grinder when an electric grinder is readily available. Don’t be
afraid to ask for the tools you need to perform your job. Air grinder, electric grinders, hammers, chisels, stamps, air ratchets, crowbars, etc… If you think there is a tool that will help you in performing your task, discuss this with your group leader. Tools that can be justified and are within reason are always a welcomed addition to our repertoire.
Running My Robot
Your station is setup, your program is allotted, and you have all the tools you need to do the job in front of you. By this point, your group leader has trained you in the part your running. We will not discuss the act of training you personally on a part, as that roll is different from job to job. However we will discuss the similarities they do share. Loading Parts
Each job is different, but the act of properly loading a part can be explained in common steps. Robots will not know if you do not n ot load the part correctly. Loading a part poorly, forgetting a clamp, or not cleaning your cone can cause permanent damage to the robot. To put a price tag on the severity of damaging a torch, a rough estimate would set the company back $1,000.00. We do understand that accidents can and do happen, however, through proper training and coaching, we are minimizing this issue. Please be consistent in loading your parts, Not all jobs require parts to be loaded in a specific sequence, but finding one and sticking to it will allow a llow you to become faster. Knowing that by putting a certain piece in first may make the rest of the parts fit in easier and faster. Always be sure that all parts are in their proper locations and are secured down with either a clamp, spring stop, or bolt. Make sure if a fixture has multiple stages or other parts that run on it, that all clamps are closed regardless of being loaded or not. All programs are written with all clamps closed. Buttons Galore As and operator, were only going goin g to discuss the main buttons you’ll need to begin and maintain production. At first, you may require help getting the robot to recover from error like “Shock”, “Arc-Fail”, and “Out of Arc”, but eventually you’ll be able to correct this yourself. Each robot has a box of button mounted to it, or near it on a stand that is considered an “Operators Box.” There are only 4 Buttons you’ll need to concern yourself with; “Start”, “Auto”, “Servo On”, and “Emergency Stop”. Start and Emergency Stop (E-Stop) is self
explanatory. Start will start or resume production on your robot, Stop will immediately stop the robot regardless of what it is doing. Auto will be used to put the robot into “Auto” mode. This must be done any time the robot is put into “Teach Mode.” This will occur anytime something needs to be adjusted or you are recovering from an error. Servo is used to turn the safety curtains back on and this will need to be done anytime you need to push the Auto button, or if the safety curtains are broken b roken accidently. Often times when a group leader will correct something using “Teach Mode” they the y will tell you, “It’s ready, Just Auto-Servo-Start”, this is the button sequence to return to running production. As you become more familiar with the robot, other buttons will be explained to you. Fixture and Part Quality
A quality part is the goal at all times. This can be hard to accomplish if your not working with quality qua lity tools, or a quality fixture. Documentation will be p rovided to explain the necessities related to creating qualit y parts. Maintaining the fixture is also the responsibility responsibility of any and all employee’s in the department. A clean fixture that is free of BB’s, dirt, debris, or other defects will hinder your ability to produ ce a perfect part. Don’t be afraid to take some time to scrape or blow off your fixture. A keen eye for this will increase your production by lowering the chances of having to fix or rework a part. Fixtures are often removed between jobs and taken to a wash booth and thoroughly thoroughl y cleaned with acid and other chemicals. As an operator it is your responsibility to notify a group leader of any problems you notice with a fixture. Error Recovery Documentation
Documentation can be provided by your group leaders that will walk you through the process of correcting a robot after it has one of the three before mentioned errors e rrors (Shock, Arc-Fail, Out-of-Arc) as well as E-Stops and properly allotting programs.
PART 2 (OTC) Intro to Programming
Every programmer starts off as an operator; having a thorou gh grasp of running the robot is essential to understanding how to program the robot. Every Operator has had those moments when they think to themselves, “Why is the robot doing this, this wa y? If I were programming this part, I would have do ne it like this.” For whatever reason, the programmer made the decision to program these parts this way. With the following knowledge and information, you will understand why, or maybe, you found a new way to run a part, that is A) Faster, B) Of Better Quality, C) More Practical, or all of the above. Robotic programming is easily mistaken as one of the more complicated aspects of weld production. p roduction. That’s not to say it can’t be intimidating at times. The first thing you need to understand about abou t a robot is that it is just a computer built to do a “Pre “P re-Programmed” task accurately and repetitively. As a p rogrammer, you will learn how to “Teach” these robots the steps and actions it will need to perform, in the sequence it will need to perform them. The best way to think of Robotic programming is three dimensional “Connect the dots”. Below is a snippet of code from one of our programs. 001 – HP 002 – HP 003 – P 100% 004 – P 100% 005 – AS (24V, 200A, 14IPM) 006 – L 100i 007 – AE (23.5V, 180A, 0.1, 0.0) 008 – P 100% At first this code may seem like a foreign language, langu age, or at the very least confusing. confu sing. What your actually seeing is the “Robotic Code” a previous Programmer has put into the robot to perform a task. All the letters and random numbers make very little sense at the moment. mo ment. This demonstration is strictly to show you the structure of the code. We will go into further detail of each function later on. It’s more important to understand the structure and sequence, then the commands. The simplest way to think of this is in English terms. The English interpretation of any Computer Code is called “Pseudo-Code”. The same code written in English or PseudoCode would look like this. 001 – This is my Home Point, or where I want the Robot to start from (Safe Position) 002 – This is where I want to turn my m y table into the proper position for my weld 003 – The robot needs to move here first at 100% of its operational speed 004 – The robot then moves here at 100% speed to begin its weld 005 – The Robot will start welding at the previously previousl y stated point, with these settings 006 – The robot will continue welding to this point, maintaining these settings 007 – The robot will then finish its weld, with these settings 008 – The robot will then move to this point, to clear the part, at 100% speed This is a lot less intimidating when you see it this way, and is far easier easier to understand. What this article will do, is train you on how to think and relate the robotic code, cod e, to our natural way of thinking. thinkin g. You will learn how to take a set of instructions we understand, un derstand, and translate them into code the robot will understand.
Programmable Points
Programmable points, such as “P”, “L”, “C”, and “HP” are known as Position Points, for lack of a better term. These points can be programmed with a physical position. Meaning, the robot will have to move to this point to execute any of commands following the point. These are your “Dots” so to speak in “Connect the dots”. Each of these points will store information on where the robot moves to. They however will each move the robot there in a separate manor. Understanding that th at manor and utilizing it properly is what defines a Programmer. “P” Points
Your “P” point is the bread and butter of all programs; it will easily make up 80% of your program. This point comes with a speed modifier, which you’ve seen earlier. The modifier is in a percentage based form, and directly affects the speed of the robot. “P” “P ” points when used will cause the robot to move in a slight hopping hop ping manor. It will take the shortest possible path to this point, rotating all axes at the same time, regardless of what is in the way. For this reason, “P’s” “ P’s” should never be used in the middle of a weld. “L” Points
Your “L” points are, as the name n ame suggests, Linear Points. These will make up a majority of your welds. These points are used mainly for welding, since they th ey move the robot in a straight line, and will adjust the axes in the appropriate way to make sure that happens. “L’s” can also be used to get into harder to reach locations, As the linear motion will allow you to sneak past things that would normally cause problems when using a “P”. The movement modifier associated with “L’s” is different from “P’s” in that it is an actual measurable speed. You’ll notice when you program an “L” point, it defaults to 100i. The “i” is short for Inches per Minute, which is exactly as it sounds. 100 inches will be moved in a linear path, in one minute. The only onl y time this number holds no value is during a weld, at which time the movement speed entered for the weld will override any values entered. “C” Points
The “C” point is used for circular welds, an d can be a little tricky to master. The most important thing to remember about programming with these points is they must be used in no fewer then three consecutive con secutive points. The robot requires three points because it will use the information gathered to calculate the proper p roper radius of the circle. Using less then three points can cause jumps jump s in speeds, bunny hopping in the torch, or errors within your program. “C’s” carry the same “i” modifier with them that “L’s” “L’s” do, and the rules are the same. “HP” Points
The final position holding point we’ll discuss is “HP” points. These points will be used to determine start and end points of your program, as well as table turns. “HP” or Home Points are the only known know n points that will record both the robot’s position, as well as your table’s position. Trying to rotate and record the table with any other point is futile and will only onl y result in the robot crashing. It is important to remember that “HP’s” will always be used in pairs when turning the table. One point will be used at the ta ble’s current location, another at its destination. This will allow the program to be blocked through forward, as well as backward. “T” Points
The next point we will discuss d iscuss has multiple purposes, and in my opinion is the most versatile point at a programmer’s disposal, the “T’ Point. This point is a Time point, and it holds no actual physical value, meaning the robot will make no movements when it encounters this point. This could be used as a “Wait” command. A programmer would be able to use this point for Tacking parts during a program, holding the robot in a certain position to perform certain tasks like cleaning the cone, letting the cone soak in a solution/gel, letting the cone drip dry for a moment to prevent porosity, po rosity, filling in plug welds, or building up a puddle before you begin b egin welding.
Welding Commands
What we’ve previously covered in essence, is 80% of what it takes to become a solid robot programmer. Being able to put your robot where you need, how you need it to be there, is a majority of creating a good program. We will now learn how to make the robot weld, where and how we want to. Just like hand welding, there is an array of variables that go into getting the “Perfect” weld. Volts, Amps or wire feed spee d, Torch angle, Torch movement speed, material thickness, Part position, fixture limitation, robot limitations. All of these will have to be answered to in order to create a program. Arc Start (AS)
The Arc Start or “AS” command, is used with your programmed points to tell your robot when and how to weld. This Command will be accompanied accompan ied with weld parameters. Just like when hand welding, we need to set these parameters for the situation we are in. Finding a combination of parameters that will work consistently is the key to creating a great program. Good parameters come with experience; don’t be afraid to ask your betters what their opinion is. The first parameter you’ll be inputting is the Voltage. This is a numerical reference to how “HOT” your weld will be. The thicker your material, the higher this number will be. This number can very depending on your position in relation to the weld, How large the weld needs to be, b e, as well as how fast the robot will be moving while its welding. The second parameter you’ll see is your Amps, or Wire Feed Speed. Depending on what size wire you are running on the robot, this number will have different meanings. Robots running .035” wire will have a 1Amp to 2IPM ratio; .045” wire will have a 1-Amp to 1-IPM ratio. This means if you were hand h and welding this part, and the parameters you decided to use had your wire speed set to 200IPM (Inches per Minute) you would be using 200Amps for .035” or 100Amps for .045”. You will have to learn both of these ratios, because our robots run both sizes of wire
The final parameter you will have to provide is the movement speed of o f the torch. This speed is recorded in inches per minute. Average speeds consist of 12 – 24ipm, but there will be times when this will not be the case. Ideally we do our best to make the robot go as fast as we safely can, while producing a quality part. This may not happen the first time a program is written, although you should always strive for this to be the case. This is another “learn from experience” parameter. This parameter can change based on your first two choices. Arc End (AE) Naturally, what follows an Arc Start, but an Arc End. You’ll see two familiar familiar parameters here that are
consistent with the Arc Start; Volts and Amperage (Wire Feed Speed). However you will notice the absence of En ter “Crater Time” and “Post Flow”. your movement speed, and in its place we have two decimal parameters. Enter Crater time, for all intensive purposes, is a built in “T” P oint. By definition, the crater time is the amo unt of time the robot will pause at the end of a weld, but continue welding at the provided parameters. You’ll notice with robots that the end of our welds, they the y tend to be smaller then the original weld size. Crater time is here to correct that. Often crater time is set to 0.2 seconds, but it can stretch from 0.0 to a full second, depending on the requirements.
Post Flow is a term you will recognize from some of the more modern MIG welders we have hav e around the shop and its functionality is the same. Post Flow is the amount of time, in seconds, the robot will remain at the end of weld releasing shielding gas to continue to protect the weld from oxygen. This helps with porosity.
Weave Start (WS)
Weaving is by far, one of the most useful functions of a robot, when it comes to welding. There is a lot the can be controlled or adjusted when it comes to inserting a weave into your weld. Weaving is usually done at all times, but there are occasions when this is not so. Usually these occasions come from limitations due to the robot or the fixture itself. As a programmer, weaving will ad size, consistency, and leave you room for error in your parameters. This command will come with setting familiar to those who understand Geometry or Calculus, Amplitude, Frequency, Stops (¼, Center, ¾). The best way to describe weaving weavin g is with a demonstration. As you can see below, all the variables are shown with the exception of the stops.
Amplitude – The amplitude is an inch measurement of the distance the cone is going to weave from the
center of the programmed weld. You will have two points to enter in here, one for each side. It is possible to weave ½ inch to the right, and an d no weave to the left. This is extremely unorthodox and not advised, but it is an example Frequency – The frequency is the distance between “waves”. A higher frequency will result in the robot weaving more times in a given distance. Often times we do not have to adjust the frequency, but there are times it will change from 3Hz-6Hz, default is 5Hz Stops are not often used, but are worth mentioning. If you were to cut c ut your weave into quarters, they make perfect sense. You can allow the robot to pause at these locations for a certain number of seconds. This would allow you to put more weld onto one side of your weave then the other. WE
A Weave End command is simply telling the robot to stop weaving. Usually this is just placed at the end of the program. If a weave needs to be changed for a certain weld, you can simply insert another WS command and adjust your settings.
