Our team is trying to curve a piece of polycarbonate into a constant 7 in radius curve for our gear holder. Right now we have it in a homemade clamp that fits the shape of the curve and using a heat gun to form it. Is this the correct method or is there another one? Any advice is appreciated. Thank You in advance.
Yeah doing that is perfectly fine. You’ll get a bend into it eventually, but I recommend using some sort of hardware like a bolt or clamp to keep it in the desired position. We did that for our gear holder as well:p
This is what we have right now.
If you don’t get the results you’re looking for switch to ~.04" thick aluminum sheet and put it through a roller to get the desired curve.
This is pretty clever actually, I might steal this for 1072.
And if you don’t have a roller, a vice and a hammer work really well too:p
Make sure to heat both sides simultaneously and to back off when you see bubbles. Our team found using two heat guns worked better than one. The darn stuff seems to take forever to get to the point of malleability and then is there all at once. I have talked with people who have simply put it into the oven and warmed it up but that won’t fly at my house. It could be a viable option if you had to bend quarter inch. We ended up making several polycarb prototypes but eventually did go with aluminum. Other parts of the machine used bent bits of thinner polycarb. T Wolter
working polycarbonate pdf i used the tip in this document to preheat and dry the polycarbonate. We bent .125 around a 1/8 hardboard frame. It all went in the oven for 2hrs at 250f then bumped to 300f for 5 min. Could try 300+ just test to find that sweet spot.
When you have bubbles, it’s already too late. You can tell when it’s soft enough by testing it by hand and/or looking to see when the surface looks warped.
Heat it slowly with two or more heat guns. Have some patience and try to to hold the gun in one spot for too long. It will eventually become very pliable. Trying to get it too hot will lead to bubbles.
You can treat the poly carbonate just like aluminum and roll the radius using a sheet metal roller. Another way to make the bend is by using a press brake and make multiple small bends into the part.
Here a link Bump Bending
If you can punch the material to might try the jig saw puzzle approach and using a tab and slot to hold the radius an and glue it together.
Take a look at this site for ideas on using different manufacturing techniques
We built forms and put it in the oven and heated it to 310 deg. It avoids the gasification that can happen when you use a heat gun.