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Now that I'm involved in making some lap steels that require templates for routing cavities in solid wood, I'm wanting some clear Lexan templates for inside cuts, rather than the material I usually use so that I can see what I'm doing more easily. Normally, I'm just cutting Lexan on an outside line on the bandsaw and sanding to the line. Can't do that with inside cuts. No problem making the MDF template pattern for routing the Lexan, but I've had a couple of instances of the router wanting to melt and grab the polycarbonate when I try to pattern rout it. Just wondering about any learned advice on router bits, speeds, tips, etc. Thanks, Bob

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“ The meaning of life is to find your gift and the purpose of life is to give it away” Pablo Picasso

Try removing most of the waste with Forster bits in a drill press so that you only have to route 1/16" plus the peaks left from the bits.

Alex

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"Indecision is the key to flexibility" .... Bumper sticker

How much are you trying to rout at once? Multiple passes are the way to go.

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https://soundcloud.com/jeffreylsuits/he ... -runnin-13

What Alex said. The less you have to take the better. Eliminate any source for vibration by clamping the lexan
down, etc. In general I find lexan a pita to route. Maybe someone else has the bees knees method to share??
Ken

If you are going to use the templates less than a couple dozen times try making them out of .25" masonite hardboard. Flood the edges with thin CA to harden them up. It doesn't take care of your visibility concern but is MUCH safer! I've heard enough horror stories to be leary of pattern routing with lexan.

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Routing lexan isn't that hard but you have to allow for the variables and Heat is the killer I use a 2 flute mill bit up cut in a blind hole and since your cutting this in a few passes you must plan for that . I will turn the router as slow as it will go. Spray the surface with water that has a touch of soap in it for coolant and lube. Take about 1/6 at a time cutting as fast as you can. The heat will go 1 of 3 places tool , work or chip. You want to get the heat in the chip. I would make a pattern then apply some tape and coat it with CA.Don't use so much that you glue the tape to the pattern.Once you are through the material remove the tape and make a clean out cut again spraying with the water and soap solution.
I used to machine a lot of lexan and polycarbonate . Lexan did cut the best so be sure you getting lexan not polycarbonate.

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John Hall
blues creek guitars
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Thanks for all the replies. Sounds like I need to slow everything down. The router, the feed, me!

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“ The meaning of life is to find your gift and the purpose of life is to give it away” Pablo Picasso

Don't slow down the feed rate - you want to keep the router bit moving across the lexan quickly, but like John said, slow down the rpm of the router. You can fine tune your process using some scrap pieces of lexan. You want shavings coming off of the bit, same as when you are routing wood.

Alex

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"Indecision is the key to flexibility" .... Bumper sticker

Shallow cuts for sure -- but a proprietary plastic cutting bit (which are single flute) goes a l long way in simplifying the process.

http://www.bamcarbide.com/acrylic.html

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Ken Cierp

http://www.kennethmichaelguitars.com/