Heating plastic

My team is thinking of implementing a curved (plastic) hood onto our robot. We were wondering how should we go about heating the plastic to curve it.

you really don’t need to.

all polycarb hoods should have a rigid frame/backing, otherwise they’ll flop around and be generally useless.

if you make your frame rigid, you should be able to attach the polycarb at a curve and the frame will keep it in shape, no heat-bending required.

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If you absolutely must, use a hair dryer, or preferably a heat gun, to bend the plastic around an object of similar curvature.

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To add to this, if you have access to a roll bending machine, you can bend a mold of a specific radius and heat the polycarbonate over that, and then cut it to the correct arc length that yields your desired exit angle. To find these values, you’re either going to be really good at geometry or just use CAD.

Ex:

Here’s a rough example of how the hood geometry is derived (from my robot):
Screen Shot 2021-02-17 at 3.14.07 PM
And how it’s since translated in practice:
IMG_8383

Additionally, I’d make another mold of a slightly larger radius and rigidly screw it into the first piece so that the polycarbonate cannot easily flex. This is an overkill solution by the way and doesn’t make sense for this year’s game. But if you insist on heat bending, this is the best way to go about it.

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Adding on to everyone else:
Polycarbonate does not need to be heated.
If you’re using a different non-shattering plastic, definitely use a heat gun first and if not, use a hair dryer. I’ve also heard heating it up in an oven can work.
Do not use an open flame or concentrated heat source. Not only will the plastic melt a little releasing toxins in the air, but you will also weaken that part of the plastic, and even leave a singe mark.

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