Cutting grooves in Lexan

I have some small pieces of 1/4" Lexan, 3.5" long. I need to cut parallel grooves in one surface, 1/16" x 1/16", spaced 1/4" apart. The best idea I've had so far is a rotary tool with a cutting wheel mounted on a board. Here's the hasty version of this rig:

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It cuts well, but it leaves curls of cuttings melted to the sides of the grooves that are a PITA to remove without scratching the Lexan:

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Any ideas how to minimize such curls, or how to remove them easily and cleanly?

Reply to
David Hakala
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Probably too much speed and the teeth aren't course enough. Cutting stuff like that calls for chip removal and cooling. Add a powerful blast of concentrated air at the point of the saw cut.

Reply to
sandman

"sandman"

Interesting. I tried a cutting wheel about 1/16" thick and 1" dia. at about

10,000 rpm. Slowing it down didn't help. Then I tried a diamond-coated wheel, a bit more than 0.12" thick, which fits the steel plate that goes into this groove perfectly. That went better but I still get melted Lexan.

I guess I need one of those itsy-bitsy circular saw blades, and I know exactly where to get one!

I suppose my vacuum cleaner will do for a powerful blast of air. :-)

Thanks, sandman!

Reply to
David Hakala

David, I was more thinking along the lines of a blow gun with air from a compressor. High pressure to blow the chips away from the action. I don't think a vacuum would have the concentrated oomph. The cooling would be a side-benefit.

I would also make sure that the travel of the work would be parallel to the blade.

Reply to
sandman

Why not use a hand-router [the motorless kind of yore] with a guide that can be clamped to parallel markings on another piece made of wood of the same thickness? You could have an outer jig frame that holds the piece and one side having the markings. You'd need a craftsman's steady hand and a razor-sharp blade. I've done it before [with wood] and used more materialfor the jig than for the object being worked on.

Reply to
Guess who

Why not put the piece in the freezer first?

Reply to
Frank

Because I've never hear of a motorless hand router, and I don't have the steady hand you mentioned, either. :-)

Reply to
NoPoliticalCalls

Because it's too dark in the freezer to see what I'm doing. :-)

Frozen Lexan. I'll have to try that for breakfast.

I bought a 3/4" x 1/32" saw blade on eBay. I hope that will eliminate the curls and make cutting easier too.

Thanks, everyone!

Reply to
NoPoliticalCalls

OK, "Router plane".

Look here:

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"Steady" is relative, and you can use a guide.

Reply to
Guess who

I was thinking along the lines of saving the cost of an air compressor. :-) I have a set of mini attachments for cleaning PCs and sewing machines that will restrict the air stream, focus it where it's needed, and increase velocity. That's the theory, anyway.

I've gone to interesting lengths to ensure that the work feeds parallel to the blade. I'm rather pleased with the results now. The melted waste is greatly reduced, and I find that I can buff it off with a fiber wheel on my bench grinder without scratching the Lexan. Still, I look forward to receiving my mini saw blade this week.

Reply to
NoPoliticalCalls

Dave...

I've had fairly good luck routing Lexan sheet stock. The smallest bit that I've used has been 1/8"; but I can't see any reason why you couldn't route it with a 1/16" bit, as long as you maintain a feed rate that avoids the heat buildup.

Looking back at my notes, I cut the 1/8" Lexan with the 1/8" two-flute spiral bit at 18000 RPM with a 1.5"/sec feed rate. I'm not sure this is ideal; but it worked for me.

Reply to
Morris Dovey

all sorts of grief. :) Liked the layout shots from one of your earlier posts btw.

I'd like to see more of your machine refinements.

Regards,

Rick

Reply to
Rick

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