3D-printing basics
Carlo Fonda, ICTP SDU
[email protected]
From printing (on paper) texts and pictures to “printing” three-dimensional objects
Fused Deposition Modeling (FDM) • Many technologies are possible for 3D printing. • The most common one uses molten (liquid) plastic extruded through a nozzle. The nozzle or the object (or more often both) are moved along the three axes X, Y, Z. • 3D printing is an "additive manufacturing" technique, opposed to the older "subtractive manufacturing" machining systems like milling machines, CNC, etc.
Professional 3D printers (10.000$+) • Pro 3D-printers can print objects • in plastic, starting from a filament (with FDM), or • in other material (like metals, ceramics, etc.) provided as powder and “assembled” by sintering (SLS) • and some are even able to print in full RGB color • Up to a (very) big size • Very expensive (“pro” market) • Beautiful results ;-)
Personal 3D printers
cost: from 300 to 3000 USD
Open source + Open Hardware • Low-cost printers use a plastic filament (ABS or PLA, 1.75 or 3mm thickness) and are usually build with a plywood or acrylic frame • the software is free and open source: 3D design apps, slicers, printer control apps, etc • they make extensive use of open hardware like Arduino, Sanguinololu, etc. (small cheap computer boards), all drawings are downloadable • some printers can (partially) replicate themselves, because are made with printed parts
Makerbot Replicator • Third generation printer (the first two were the Cupcake and the Thing-o-Matic) • Single or Dual head (can print in two colors, or two plastic types)
RepRap: Prusa/ Mendel/Darwin/etc... • Many variations on the theme • Mostly designed (and marketed) by members of the hacker community in US and Europe • Everything is open, you can buy or build/modify them
Not only from U.S.: the Ultimaker • Developed in the Netherlands by a student (as a byproduct of his MSc thesis) • €1194 fully open source • Also CB-printer produces a nice Prusa derivative in Poland (full aluminum frame) • In Italy: the PowerWASP 3Dprinter, made by the WASP Project (it becomes a CNC by simply adding a Dremel)
Printrbot • There are two very portable models, battery powered.
The Cube • First cheap commercial "notfor-hackers" plug'n'play printer • For children, families, etc. • Also MakerBot's Replicator 2 is going on this track (less "open", but for a much larger market)
The Cube ($1299)
Makerbot Replicator 2 ($2199)
And many more... • Different solutions • Different level of skills required to operate • Different prices • Different philosophies • The market is growing and still searching an equilibrium...
Laser + liquid resin • a new printer by Formlab: it uses a special liquid resin that costs 3x more than plastic, has better resolution and precision.
History of the Personal Computer (is it repeating all again?)
Pro only
first personal (for hackers)
really personal (mass produced)
?
???
Any market for 3D printing?
many think so
N=1
The long tail
by Chris Anderson
Cloning objects • Combining 3D scanners with 3D printers, it becomes possible (and affordable) to make copies (1:1 or scaled) of objects (even at a distance!)
This summer, the Metropolitan Museum of Art held an event to make 3D scans and prints of works from throughout the museum. Participants used digital cameras and Autodesk’s 123D Catch to generate the 3D models, and then printed them using MakerBot Replicators.
Met3D
Making new objects • 3D printing isn't just about copying objects, but also about creating new things, that are impossible (or expensive, or difficult) to make with other technologies. At home!
Thingiverse & C. • www.thingiverse.com (specifically for 3D printing) • www.grabcad.com (complex models, made for photo-rendering, maybe just 5% are printable) • People sharing a LOT of 3D modifiable object models • (almost) all are free, without DRM
Cubify & C.
3D printing for humans
it isn't just for fun...
3D printing for the Developing World
... there are already some ideas
•The Challenge launched on the 1st May 2012 . •In May and early June 2012, techfortrade ran innovation workshops in the UK,
USA, India, Kenya, South Africa and Romania to stimulate ideas. •Over 60 projects were submitted from individuals and organisations in the Americas, Europe, Asia, and Africa. •A shortlist of seven finalists was selected from initial entries. The finalists received a $1,000 research budget in order to further develop the concept in advance of the final selection event. •The final was held in London on October 19th 2012, as part of the first 3d Print Show. •The winning project came from the University of Washington in Seattle. Washington Open Object Fabricators (WOOF) won The 3D4D Challenge and a prize of $100,000 to help towards implementing the project. •WOOF’s winning project will enable waste plastic to be used as filament for 3D printing machines, to create new products. The winning team, Bethany Weeks, Matthew Rogge and Brandon Bowman, plan to work with US based NGO, Water for Humans (WFH), to address local issues in water and sanitation in Oaxaca, Mexico.
The 3D4D Challenge: Relieving Poverty, Encouraging Innovation
http://www.3d4dchallenge.org
http://www.textually.org/3DPrinting/cat_3d_printing_for.html
One project described here caught my eye. Called Happy Feet, it was one of the contestants in The 3D 4D Challence which took place in London last October. The slogan was “Relieving Poverty Encouraging Innovation.” Among the contestants were Roy Ombatti and Harris Nyali from University of Nairobi’s Fablab. Their project, Happy Feet, aims to solve the jigger menace in Kenya by using 3d printing to make customised shoes for people suffering from Jigger. Thus a right shoe can be made differently than a left, depending on the level of infestation. Jiggers are tiny parasites that resemble fleas. They embed themselves in the feet, hands or other exposed body parts of animals, including humans. Serious infestations may lead to severe inflammation leading to loss of toenails, auto amputation of digits, and death may also occur. The risk of secondary infection, such as tetanus, is also high. Jiggers live in dusty conditions and other unhygienic environments, and are generally associated with poverty-stricken populations.
“The shoes would be manufactured from reused plastic and would also be recyclable once they are worn out. Apart from the potential help that this project could bring to people affected by the jigger infestation, it can also provide employment for people.”
3D printers for science?
... we are investigating
An article on Nature http://www.nature.com/news/science-in-three-dimensions-the-print-revolution-1.10939
UK just opened a new £6M research centre • ...and they are looking for young physicists and engineers
Archeology in 3D • Old bones made of plastic? • Louise Leakey (a 3rd generation archeologist ;-) and her latest initiative: "AfricanFossils"
http://africanfossils.org
At the ICTP too! • "Beeswax as Dental Filling on a Neolithic Human Tooth" Federico Bernardini, Claudio Tuniz et al., 2012 PLoS ONE 7(9): e44904.
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STOM TOOLS
themappa meantime, basic plasticstampa 3D printers aredi starting to allow tattile per ipovedenti di un modello mano stampa con plastica flessibile ICTP, Laboratorio di Stampa 3D earchers to knock out customized tools. Leroy Cronin, a chemist he University of Glasgow, UK, grabbed headlines this year with invention of ‘reactionware’ — printed plastic vessels for smallle chemistry (M. D. Symes et al. Nature Chem. 4, 349–354; 2012). Concorso rivolto agli studenti delle scuole secondarie superiori onin replaced the ‘inks’ in a $2,000 commercially available printer delle Provincie di Gorizia th silicone-based shower sealant, a catalyst and reactants, so that e Trieste ire reaction set-ups could be printed out. The point, he says, is to Le 5 migliori idee proposte dagli studenti verranno riprodotte usando una delle nuove ake customizable chemistry widely accessible. His paper showed a basso costotodel Laboratorio di Stampa w stampanti reactionware3D might be harnessed produce new chemicals or to 3D dell’ICTP per la produzione di keoggetti tiny amounts of specific pharmaceuticals on demand. now, cm). in plastica di piccole dimensioni (max. For 20x20x20 herPer chemists see the idea as a clever gimmick, and are waiting to see favorire la conoscenza e creatività dei giovani studenti, la Science Dissemination Unit (SDU) del Centro Internazionale atdiapplications follow. Fisica Teoricawill (ICTP) di Trieste promuove un concorso aperto a tutte le scuole secondarie superiori delle Provincie di Researchers in other fields have found Gorizia e di Trieste. Potranno partecipare al concorso gli studenti che frequentano i Licei, Istituti Tecnici e Professionali, a more immediate use efor the technology. nonché coloro che frequentano corsi di Istruzione Formazione Professionale Regionale. Philippe Baveye, an environmental engineer at Per informazioni sul concorso visita il sito: http://1mm.it/idea3d Rensselaer Polytechnic Institute in Troy, New
STAMPA LA TUA IDEA IN 3D
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HOW do I print an object?
...practical 3D-printing for beginners
#1 - Design a model • The first step for creating a 3D-printed object is to make a digital model of it. • There are many CAD programs (Computer-aided Design software), some are even free and open source. • To learn how to use well a CAD program is not easy, it may require some days (or months) and a lot of patience and practice...
Program VS WebApp • Sometimes, for a simple model, is easier and quicker to use one of the specialized websites that provide visual tools for an easy and immediate creation and/or modification of your 3D models (these are called webapps). • Examples (more will follow later, with a short demo): • TinkerCAD (now closing) • 3Dtin • ShapeSmith • Cubify
Examples: free software for technical 3D modeling • SketchUp (by Trimble, was: by Google) DEMO time after this boring lecture! ;-)
• FreeCAD (open source, Win/Mac/Linux) • Blender (open source, Win/Mac/Linux) • Autodesk Inventor Fusion (Win/Mac) Now: Fusion 360 (beta)
• OpenSCAD (programming language) • and many others...
SketchUp: http://www.sketchup.com
Examples: free software for artistic 3D modeling • Sculptris (Win, Mac; DEMO time later, by Gaya) • Autodesk 123D Design (Mac, Win, iPad, web) • and a few beautiful webapps (e.g. Nervous System)
Sculptris: http://pixologic.com/sculptris/
File format: STL (StereoLithography) An ASCII STL file begins with the line: solid name where name is an optional string. The file continues with any number of triangles, each represented as follows: facet normal ni nj nk outer loop vertex v1x v1y v1z vertex v2x v2y v2z vertex v3x v3y v3z endloop endfacet where each n or v is a floating point number in sign-mantissa 'e'-sign-exponent format, e.g., "-2.648000e-002". The file concludes with: endsolid name The structure of the format suggests that other possibilities exist (e.g., facets with more than one 'loop', or loops with more than three vertices) but in practice, all facets are simple triangles.
[source: Wikipedia]
Free iPad Apps for 3D modeling with a “touch” • netfabb (STL viewer only) • MeshLab (STL viewer only) • other viewers (3Dskope, KiwiViewer, vueCAD) • Autodesk: 123D Sculpt (“rounded”), 123D Design (“squared”) • Autodesk 123D Catch (3D scanning with iPad/iPhone camera) • Autodesk 123D Make (cardboard 3D models! ;-)
#2 - Check & repair • The STL files that have been created by the modeling software may not be yet ready for printing, they should be checked for problems. • Software for control and repair: • netfabb Studio Basic • MeshLab (conversion too) • Software for visualization: • Pleasant3D (Mac only)
#3 - Slice • Here comes the fun... • In order to print, the model (STL file) should be first converted into a set of instructions (a common one is called G-code) that tell to the printer how to move the printing head, when and how much plastic to extrude, etc. • This is called slicing, and your model is now a pile of layers. • This is the MOST CRITICAL part of the whole process, the final quality of the printed object is determined almost entirely by a correct choice of values for the many different slicing parameters.
So, the next lesson will be on:
SLICING, SLICING, SLICING...
#4 - Prepare the printer • calibrate (level) the platform (printing bed) and clean it • pre-heat the printing head • load the plastic filament into the extruder • extrude some plastic, in order to fill the nozzle • start the print ;-)
#5 - Wait until finished • Printing time for a small object can be 10-20 minutes. • For an object the size of an apple, can be up to 1 hour and more (it depends on resolution, infill, and printer speed). • Bigger objects can take 10+ hours, complex ones even 20+ hours... • May be dangerous to leave a 3Dprinter completely unattended when printing (T > 200ºC, melted plastic, electricity, moving parts, wooden frame...).
#6 - Finishing • After the print, you may want to give a few minutes for the object to cool down (it will be easier to detach it from the bed). • You may have to remove raft/ support structures. • If needed, the object surface can be smoothed by using sandpaper (it may ruin the finishing), a chemical solvent (i.e. Acetone for ABS), heat (hot air blower) or a coating paint.
A world of plastic
don’t pollute, 3D-print!
Many types of plastics • ABS (Acrylonitrile Butadiene Styrene), petroleum based plastic (used for the Lego™ bricks) • PLA (Polylactic Acid or Polylactide), a biodegradable plastic made out of plant starch • 618 Nylon (®Taulman) • PVA (Polyvinyl Alcohol), water-soluble • HIPS (High Impact Polystyrene), soluble in Limonene • others: soft PLA, temperature-sensitive plastic, wood-based, conductive, etc...
Filament • Filament comes in two standard diameters, 1.75 mm and 3.0 mm. The 3.0 mm filament is somehow an older standard and is slowly being upstaged by the 1.75 mm because it can be pushed slightly more easily, controlled a little better and sometimes leaves fewer tails hanging off the sides of your object. • Cost: around 35$ (30€) per kg. • 1g of printed object ~ 0.03€
Recycling plastic www.perpetualplasticproject.com • make 3D-printed objects from recycled plastic
What can we PRINT?
(with our low-cost 3D printers)
Small is beautiful • Common low-cost 3D-printers can print objects with dimensions of less than 20x20x20cm • In some models isn’t very difficult to increase the vertical size. Horizontal limits are harder to break. • It is still possible to build larger object by combining together multiple parts (with glue, screws or joints). • Big printings take a LONG time! • The final dimensions of the object may slightly differ from what is expected, because of thermal contraction of plastic. Make some tests!
Start with the right 3D model (STL) • It is important to create watertight meshes in your design, so that it is clear to the 3D printer what is the “inside” (which needs to be made up of 3D print material) and what is the “outside”. In short, ‘watertight mesh’ means that there are no holes, cracks or missing features on the mesh. • Another source of troubles is a mesh with flipped triangles. They should be reversed to the proper orientation before the slicing. • Software repairing tools are available (netfabb, MeshLab).
Details that make the difference... • Small details are difficult to print: the diameter of the nozzle is usually in the range 0.3–0.5 mm, the head/platform movement resolution is ~0.1 mm. • A typical value for layer thickness is 0.2 mm (range: 0.05–0.5 mm).
1mm
0.2 mm layer thickness
Slicing software: art, science, and pain in the neck ;-)
Solution: do many tests, and compare the results...
Beware of overhangs! • 3D printers generally handles overhangs up to 45 degrees well without special tricks. • If possible, rotate the 3D model in order to minimize the parts with an overhang (before slicing). • Point a fan at the part during the print, to cool the filament as soon as it comes out of the nozzle (before it has a chance to droop and ruin the print). • Turn on support material in the slicing software. This is a hassle because the process uses more plastic, takes longer to print, and you have to clean off the support material with a knife afterwards.
Support me, please! • FDM-based printers usually cannot produce stalactite-like structures as well as extreme overhangs, since they would be unsupported during the build. If these cannot be avoided, an extra thin support structure may be added into the object, which can be broken or cut away after the print process. • Most slicing software can create automatically such support structure.
CLEANING PROCESS
BEFORE AFTER
Raft and Skirt • Objects can be built on top of a “raft” of disposable material (i.e. the same plastic of the print and the support) instead of directly on the build surface. The raft is larger than the part and so has more adhesion. It can also prevent warping.
support
raft
skirt
• Sometime, when the print starts the filament is barely dribbling out of the empty nozzle. To solve this problem, a little bit of extra plastic can be extruded around the object before starting the actual print. This is called skirt.
Printing bed (platform) • The goal is to stick the object onto the platform. A few solutions are: • bare glass (or mirror) • bare plywood or aluminum • PLA: glass/plywood/ aluminum covered by a layer of blue tape • ABS: same, covered by Kapton tape and heated (~100+ ºC) • or use some (spray) glue...
Note: a non-heated bed can’t print ABS
Filling the empty • 3D printing is an additive process. That means you aren't paying for a machine to take material away, but to build material up. So the less material your design needs (e.g. the less volume), the lower the cost. • For this reason, most of the objects are printed with the infill parameter set to a value in the range: 10% to 50% • Robustness is obtained with the proper number of perimeters (shells), and bottom/top layers.
Good 3D-printing is difficult...
IDEAL
LIKELY TO BE
WORST CASE
Thank you for your patience!
(Oh yes, 3D-printed chocolate! ;-)
