FTC:3D Printing

3D printing is a major part of FIRST Tech Challenge because it allows teams to create parts they have designed. Teams can also use 3D printing to quickly create and prototype parts for their robots. To get started teams will have to learn how to use CAD to create the part they want or find parts available on websites like Thingiverse. Once a team has a part they want to print they will then need to use a slicer such as Cura to prepare the file to print. Teams are then able to print the part on a printer.

Pros

• Easy way to prototype parts
• Readily accessible at libraries and schools

Cons

• Higher end printers can be expensive
• Aren’t as strong as metal parts

Types of 3D Printing

There are several types of 3D printing FTC teams use, but the most common type is FDM.

FDM

Fused Deposition Modeling (FDM) creates parts by layering filament onto a build plate. The plastic is placed by an extruder that is heated to above 200^oC. Some FDM printers are able to print in multiple filaments and colors at once. FDM printing is the most common type of printing among FTC teams.

Pros

• Can be cheap
• Commonly at libraries and schools

Cons

• Can sometimes produce brittle parts

PolyJet

PolyJet printing places a layer of plastic that is then cured and hardened by UV light. PolyJet printers are able to print with multiple filaments and colors at once. PolyJet printers are expensive and typically cost several thousand dollars. Some companies that possess PolyJet printers may be willing to let teams use them.

Pros

• Strong
• Typically has a larger print bed than a FDM printer

Cons

• Expensive or has to be created by a sponsor

SLA

Stereolithography (SLA) is a form of resin printing. The printer uses a laser to harden resin in a vat to create a layer. The layer is then raised before creating the next layer. Parts created using SLA have a nice finish and are very detailed but they are very brittle and aren’t suited for structural parts.

Pros

• Parts have a nice surface finish
• Parts have a high level of detail

Cons

• Creates brittle parts
• Creates weak parts

SLS

Selective Laser Sintering or SLS is a form of 3D printing that uses a laser to melt plastic powder into a part. It works by layering plastic powder onto the build plate from a holding tank and then selectively fusing particulates together with a CO2 laser. The printer then repeats this process until the part is complete. SLS printers aren't typically seen in FTC because of how complicated and expensive they are.

Pros

• Doesn't need supports
• Easy to print many parts together

Cons

• Expensive
• Requires a lot of power to run

Types of Filament

The plastic used to create 3D printed parts is called filament. There are many filaments available but here are some of the most common filaments used in FTC.

PLA

PLA is the most commonly used filament in FTC. It prints at a low extruder temperature and doesn’t warp easily. It is non-toxic and can come in many different colors. It is good for many different parts used by FTC teams but other filaments may work better than it in some applications.

Pros

• Low printing temperature
• Doesn’t warp

Cons

• Not as strong as other filaments

ABS

ABS is a very durable filament. It is better than PLA in many respects except that it is harder to print. ABS prints at a higher extruder temperature than PLA and requires a heated bed as it tends to warp. It also requires an enclosure as it produces toxic fumes as it is melted. ABS is good for making structural parts.

Pros

• Strong

Cons

• Creates toxic fumes
• Tends to warp

PETG

PETG is similar to ABS in that it is a strong filament. It doesn’t require an enclosure but it does print at a higher temperature than PLA. It also doesn’t warp as much as ABS. PETG is good at making strong, structural parts.

Pros

• Strong

Cons

• Prints at a high temperature
• Can warp

TPU

TPU is a flexible filament that can have many applications in FTC. It can be used to create belts or be used in intake systems. It prints at similar temperatures as PLA but has to be printed slowly because of how flexible the filament is. Many sites recommend it to be printed at 20 mm/s. When printing TPU teams are able to change the print density, layer height, wall count, and design of the part to change how flexible the print will be.

Pros

• Flexible
• Low print temperature

Cons

• Hard to print
• Has to be printed slowly
• High bed temperature

3D Printing Accessibility

Printers are commonly accessible at many high schools and libraries to students. Teams are also able to buy printers online. Some can just be bought and plugged-in and be ready to print with. Others need to be assembled and can be a good way for a team to learn how 3D printers work, but can sometimes need a lot of maintenance. Depending on how hands-on teams want to be with a printer will determine which type they want to buy.

Additional Resources

• Thingiverse
• Cura