Quote:
Originally Posted by cbale2000
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.
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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.