Re: 3D printed parts
 

As far as printing goes, we're using it all over. We've got motor mounting spacers, ball control "tusks," levers for actuating things hooked to pneumatics, and so on.

My favorite use so far is our compact pan/tilt setup.

Re: 3D printed parts
 

There was a team that 3D printed their entire chassis a year or two ago, and I don't think the materials rules have changed all that much since then. There's actually a picture of it here on CD somewhere but I couldn't find it in a search.

Re: 3D printed parts
 

We are the team that prints robots.

http://rohawktics.org/meet-robots/

All the posts above are good and accurate. We use ABS for low load applications (sensor brackets), Ultem for moderate loads (shaft hubs for low power actuators). We have used the metal printers for bumper brackets and high load brackets. In Rebound Rumble and Ultimate Assent, our chassis was Ultem and it stood up to the loads of competitions. We used a new printer, BAAM, to print the chassis for Arial Assult and Recycle Rush. It uses carbon fiber reinforced ABS. Our first chassis this year was printed but cracked after a few days of driving over defenses so we are using pultruded material on the chassis. This year is going to be brutal so use caution. We pride ourselves on printing but have been conservative this year because of how brutal we think the competition will be.

As far as catching fire, yes it is possible if you try. But it's not easy. Plastics are hydrocarbons and can burn. Go to YouTube and look for tires burning. There is a company actually printing ABS solid fuel rockets. But I'd put the odds at zero that this will happen in a FIRST application. Your part would soften and fail long before it would burn. ABS gets soft at 105 C, melts at 205 C, can't recall ignition temp but it's pretty high.

Your biggest consideration should be layer strength. Most ABS parts have an ultimate strength of 4000 to 5000 psi in the layer but it drops to 2000 to 3500 in the layer to layer direction.

I've got ALOT of experience printing and am happy to help if you have any questions. Go to YouTube and check out Printed Cobra or Strati. We used the the technology to print HVAs robots.

Re: 3D printed parts
 

Like other posters have mentioned the parts are legal and we have been putting parts on the robot for several years. We currently have 8 3D printers in the school we work out of (6 of them were built from kits by students) plus I have 3 at home. The other day we had 7 of them all printing jobs at once.

The key is what kind of stress is the part under.
We started out printing little wrenches as hand outs.
We print a lot of covers and caps for electronics and motors.
We have designed and printed multiple encoder mounting solutions.
Camera and sensor cases are another use.
And we have printed a few more functional mechanical parts.
For Aerial Assist we 3D printed the shaft coupler for our intake. For that item we used Nylon and printed it lying flat so that the layer bonding was not subject to a lot of stress but then we had to make sure the shaft hole bridged properly.

The key is to design the part for 3D printing making note of: overhangs, bridges, wall thickness, and what axis for layer bonding vs stress. For example, vertical wall thickness should be kept as thin as possible as thick walls will often cause warping. Depending on the application, I like to make my walls all a multiple of the extrusion width. Another tip is to make sure you use fillets to strengthen joints.

Time is another issue. We are printing some gear box covers now that are 9+ hour prints. This is hard in a school as we can not have printers running when we are not there. (Hence we print stuff on my printers at my house where I have a fire suppression system installed.) Any parts you don't bag would be considered part of your withholding allowance, but thankfully they do not weigh a whole lot.

Materials are becoming more and more varied. PLA is nice but brittle. ABS is less brittle but warps. Various nylons have become some of our favorites given their high tensile strength and good layer bonding. PET-G is another good alternative to ABS. We have printed some flexible rubber items, and I am looking to test print some foam like parts for this year also.

Re: 3D printed parts
 

I was impressed with my 3D printed wheel hubs. Then I looked up your robots :yikes: Ultimately cool!!

I am guessing you work in the 3D print industry. Serious question: any chance that BAAM is available to purchase - for a somewhat reasonable price - by school districts any time soon?

Re: 3D printed parts
 

Thanks for the compliment. 3824 works in Oak Ridge National Lab's Manufacturing Demonstration Facility. The BAAM is a relatively new technology we've developed and is being commercialized by Cincinnati Inc. Go to YouTube and search for printed Cobra. The BAAM goes for $1M so don't expect it in a school soon. However we are working on a medium sized system with Cosine Additive that is more in line with educational systems.

Good luck. Post pictures of what you are printing.

Re: 3D printed parts
 

On 2910 we use 3d parts in non-load bearing places 99% of the time. They typically don't catch on fire but they technically are flammable, so if they get hot enough they can theoretically ignite, however that is a rather extreme case. This year our team has a Rhino Track based drive module, courtesy of Andymark, and when we encountered a problem woth the track pulleys, we 3D printed replacments. These are very large, solid parts, and do support a load, but most 3D prints will not. You should be strategic and limiting in your use of additive construction parts, so as not to reduce your robot's structural integrity.

-Jacob