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:

www.nopoliticalcalls.com/grooves.jpg

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:

www.nopoliticalcalls.com/cuttings.jpg

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

In article ,
"David Hakala" wrote:

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:

www.nopoliticalcalls.com/grooves.jpg

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:

www.nopoliticalcalls.com/cuttings.jpg

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




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.

"sandman"
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.

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!

In article ,
"David Hakala" wrote:

"sandman"
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.

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!



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.

On Fri, 31 Dec 2004 19:43:30 -0500, sandman
wrote:

In article ,
"David Hakala" wrote:

"sandman"
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.

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!



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.

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.

"David Hakala" wrote in message
...
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:

www.nopoliticalcalls.com/grooves.jpg

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:

www.nopoliticalcalls.com/cuttings.jpg

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




Why not put the piece in the freezer first?

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

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!

On 31 Dec 2004 23:28:49 -0800, wrote:

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

OK, "Router plane".

Look he
http://www.stanleytools.com/default....c=Router+Plane

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

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.

David Hakala wrote:

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:

www.nopoliticalcalls.com/grooves.jpg

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:

www.nopoliticalcalls.com/cuttings.jpg

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

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.

--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto/solar.html