I have a little project where I want to mill some holes and slots in
1/8" Lexan (polycarbonate).

What is the best way to do it. Really fast feeds, medium speeds, and
lots of coolant?

i

On Fri, 03 Sep 2010 12:20:18 -0500, Ignoramus24760
wrote:

I have a little project where I want to mill some holes and slots in
1/8" Lexan (polycarbonate).

What is the best way to do it. Really fast feeds, medium speeds, and
lots of coolant?

i
Make a sandwich is the key, AL on top and below. Then speeds and
feeds for AL. HSS works better here.

Karl

In article ,
Ignoramus24760 wrote:

I have a little project where I want to mill some holes and slots in
1/8" Lexan (polycarbonate).

What is the best way to do it. Really fast feeds, medium speeds, and
lots of coolant?

Clean all the oil from the tools and fixtures, as polycarb will craze form oil.
(Do not use emulsion coolant either.)

Use lots straight tap water as a coolant. Go as fast as you can without the
polycarb softening from the heat.

Polycarb can be a bit grabby.

Joe Gwinn

On 2010-09-03, Joseph Gwinn wrote:
In article ,
Ignoramus24760 wrote:

I have a little project where I want to mill some holes and slots in
1/8" Lexan (polycarbonate).

What is the best way to do it. Really fast feeds, medium speeds, and
lots of coolant?

Clean all the oil from the tools and fixtures, as polycarb will craze form oil.
(Do not use emulsion coolant either.)

Use lots straight tap water as a coolant. Go as fast as you can without the
polycarb softening from the heat.

Polycarb can be a bit grabby.


Joe, I have my chip shield made from polycarbonate. It sees plenty of
oil, but does not seem to craze?

i

On Sep 3, 1:50*pm, Ignoramus24760 ignoramus24...@NOSPAM.
24760.invalid wrote:
On 2010-09-03, Joseph Gwinn wrote:





In article ,
*Ignoramus24760 wrote:

I have a little project where I want to mill some holes and slots in
1/8" Lexan (polycarbonate).

What is the best way to do it. Really fast feeds, medium speeds, and
lots of coolant?

Clean all the oil from the tools and fixtures, as polycarb will craze form oil. *
(Do not use emulsion coolant either.)

Use lots straight tap water as a coolant. * Go as fast as you can without the
polycarb softening from the heat.

Polycarb can be a bit grabby.

Joe, I have my chip shield made from polycarbonate. It sees plenty of
oil, but does not seem to craze?

i- Hide quoted text -

- Show quoted text -

Window-grade stuff has an anti-scratch coating on it, which may slow
things down. Anywhere you've got a hole that's exposed to oil,
though, it'll start cracking eventually. Won't be instantaneous.
Doesn't necessarily have to be mineral-based oil, either, have a look
at how many Stir-Crazies are in the thrift shops without tops,
vegetable oil did them in.

Stan

In article ,
Ignoramus24760 wrote:

On 2010-09-03, Joseph Gwinn wrote:
In article ,
Ignoramus24760 wrote:

I have a little project where I want to mill some holes and slots in
1/8" Lexan (polycarbonate).

What is the best way to do it. Really fast feeds, medium speeds, and
lots of coolant?

Clean all the oil from the tools and fixtures, as polycarb will craze form
oil.
(Do not use emulsion coolant either.)

Use lots straight tap water as a coolant. Go as fast as you can without
the
polycarb softening from the heat.

Polycarb can be a bit grabby.


Joe, I have my chip shield made from polycarbonate. It sees plenty of
oil, but does not seem to craze?

Hmm. Good point. The chip shield on my lathe is none the worse for wear
either.

I may be mixing polycarb up with acrylic. Unless the heat of machining allows
the oil to get deeper into the material.

I did a little looking:
http://www.practicalmachinist.com/vb...arbonate-19645
9/.

It is the acrylic that is so oil sensitive. But still, water is the best
coolant.


Joe Gwinn

Joseph Gwinn wrote:

Joe, I have my chip shield made from polycarbonate. It sees plenty of
oil, but does not seem to craze?

Hmm. Good point. The chip shield on my lathe is none the worse for wear
either.

I may be mixing polycarb up with acrylic. Unless the heat of machining allows
the oil to get deeper into the material.

I did a little looking:
http://www.practicalmachinist.com/vb...arbonate-19645
9/.

It is the acrylic that is so oil sensitive. But still, water is the best
coolant.


Joe Gwinn


Lexan is the one that will craze like crazy.


--

Richard Lamb

Bob Engelhardt wrote:
CaveLamb wrote:
Lexan is the one that will craze like crazy.

Lexan is a brand name (GE's ?) of polycarbonate. Bob

It's the only one I have any direct experience with.

One windshield crazed (almost to dust) the first time
it got a little gas on it.

The replacement didn't and still flies.

Both surfaces are not always treated.
And it seems to matter which way the sheet is bent.

Bending the surface away from the solvent (ok, solvent contacting
a convex (treated!) surface?) will react badly and quickly.

Solvent contact on the concave side, not so reactive.




--

Richard Lamb

On Fri, 03 Sep 2010 13:58:33 -0500, Karl Townsend
wrote:

On Fri, 03 Sep 2010 12:20:18 -0500, Ignoramus24760
wrote:

I have a little project where I want to mill some holes and slots in
1/8" Lexan (polycarbonate).

What is the best way to do it. Really fast feeds, medium speeds, and
lots of coolant?

i
Make a sandwich is the key, AL on top and below. Then speeds and
feeds for AL. HSS works better here.

Karl

i just read the rest of your thread...

I didn't mention I run this dry. The AL does two things - holds the
Lexan firm for no chipping top and bottom, and its a great heat sink
so you don't get any melting.

karl

On 2010-09-03, CaveLamb wrote:
Joseph Gwinn wrote:

Joe, I have my chip shield made from polycarbonate. It sees plenty of
oil, but does not seem to craze?

Hmm. Good point. The chip shield on my lathe is none the worse for wear
either.

I may be mixing polycarb up with acrylic. Unless the heat of machining allows
the oil to get deeper into the material.

I did a little looking:
http://www.practicalmachinist.com/vb...arbonate-19645
9/.

It is the acrylic that is so oil sensitive. But still, water is the best
coolant.


Joe Gwinn


Lexan is the one that will craze like crazy.



I have come polycarbonate junk, I will try to machine it today.

"Joseph Gwinn" wrote in message
...
In article ,
Ignoramus24760 wrote:

On 2010-09-03, Joseph Gwinn wrote:
In article ,
Ignoramus24760 wrote:

I have a little project where I want to mill some holes and slots in
1/8" Lexan (polycarbonate).

What is the best way to do it. Really fast feeds, medium speeds, and
lots of coolant?

Clean all the oil from the tools and fixtures, as polycarb will craze
form
oil.
(Do not use emulsion coolant either.)

Use lots straight tap water as a coolant. Go as fast as you can
without
the
polycarb softening from the heat.

Polycarb can be a bit grabby.


Joe, I have my chip shield made from polycarbonate. It sees plenty of
oil, but does not seem to craze?

Hmm. Good point. The chip shield on my lathe is none the worse for wear
either.

I may be mixing polycarb up with acrylic. Unless the heat of machining
allows
the oil to get deeper into the material.

I did a little looking:
http://www.practicalmachinist.com/vb...arbonate-19645
9/.

It is the acrylic that is so oil sensitive. But still, water is the best
coolant.


Joe Gwinn

Igor,

I've milled plenty of acrylic using the Hansterfer S500 coolant that you
have and there has been no crazing in any of it. Some of the parts date
back nearly 3 years and I'd guess that would be enough time for crazing to
become visible..

On 2010-09-04, Mike Henry wrote:

"Joseph Gwinn" wrote in message
...
In article ,
Ignoramus24760 wrote:

On 2010-09-03, Joseph Gwinn wrote:
In article ,
Ignoramus24760 wrote:

I have a little project where I want to mill some holes and slots in
1/8" Lexan (polycarbonate).

What is the best way to do it. Really fast feeds, medium speeds, and
lots of coolant?

Clean all the oil from the tools and fixtures, as polycarb will craze
form
oil.
(Do not use emulsion coolant either.)

Use lots straight tap water as a coolant. Go as fast as you can
without
the
polycarb softening from the heat.

Polycarb can be a bit grabby.


Joe, I have my chip shield made from polycarbonate. It sees plenty of
oil, but does not seem to craze?

Hmm. Good point. The chip shield on my lathe is none the worse for wear
either.

I may be mixing polycarb up with acrylic. Unless the heat of machining
allows
the oil to get deeper into the material.

I did a little looking:
http://www.practicalmachinist.com/vb...arbonate-19645
9/.

It is the acrylic that is so oil sensitive. But still, water is the best
coolant.


Joe Gwinn

Igor,

I've milled plenty of acrylic using the Hansterfer S500 coolant that you
have and there has been no crazing in any of it. Some of the parts date
back nearly 3 years and I'd guess that would be enough time for crazing to
become visible..


Mike, I totally love that coolant. It is the best!

Has yours started to rot or stink yet?

i

"Ignoramus31991" wrote in message
...
On 2010-09-04, Mike Henry wrote:

"Joseph Gwinn" wrote in message
...
In article ,
Ignoramus24760 wrote:

On 2010-09-03, Joseph Gwinn wrote:
In article ,
Ignoramus24760 wrote:

I have a little project where I want to mill some holes and slots in
1/8" Lexan (polycarbonate).

What is the best way to do it. Really fast feeds, medium speeds, and
lots of coolant?

Clean all the oil from the tools and fixtures, as polycarb will craze
form
oil.
(Do not use emulsion coolant either.)

Use lots straight tap water as a coolant. Go as fast as you can
without
the
polycarb softening from the heat.

Polycarb can be a bit grabby.


Joe, I have my chip shield made from polycarbonate. It sees plenty of
oil, but does not seem to craze?

Hmm. Good point. The chip shield on my lathe is none the worse for
wear
either.

I may be mixing polycarb up with acrylic. Unless the heat of machining
allows
the oil to get deeper into the material.

I did a little looking:
http://www.practicalmachinist.com/vb...arbonate-19645
9/.

It is the acrylic that is so oil sensitive. But still, water is the
best
coolant.


Joe Gwinn

Igor,

I've milled plenty of acrylic using the Hansterfer S500 coolant that you
have and there has been no crazing in any of it. Some of the parts date
back nearly 3 years and I'd guess that would be enough time for crazing
to
become visible..


Mike, I totally love that coolant. It is the best!

Has yours started to rot or stink yet?

i

Nope, even the change out that's been drying it in 5-gal bucks for the past
few months has no odor. I use de-ionized water to dilute it though, and the
lack of minerals may inhibit biological growth.