cutting gasket material

[mtylerfl]

If you watch this video, the beginning shows you how to alter a vectric post processor so that it does not turn on your spindle. You can also remove the
SO,1,1
manually from any file. If you go with sheetCAM to generate your tool paths, the post processor does not include the command to turn the spindle on.

What video?

[JohnCoker]

I ordered the drag knife, since that seems to be the best option. While waiting for the cutter to arrive, I decided the try using a normal end mill and sandwiching the gasket material between plywood and acrylic. It produced a usable part, but not a thing of beauty due to the rough edges.

gasket1_1.jpg

gasket1_2.jpg

gasket1_3.jpg

[gbradley]

Here are some pictures of cutting some fixture gasket.

drag knife fixture.jpg

acrylic fixture.jpg

[JohnCoker]

Can you use the Z-zero plate with the drag knife or is that too much force on the corner of the blade?

[bleeth]

As an experiment you can make a custom zeroing file that moves the head more slowly.
That should work, but I haven't tried it as I don't do knife cutting.

[donek]

Can you use the Z-zero plate with the drag knife or is that too much force on the corner of the blade?

I use it all the time. There is little to no force applied to the tip. We do perform a series of test cuts afterwards to ensure we are cutting all the way through the material though. I have a program that allows any person in the shop to successfully instal and setup the drag knife. You would likely want to change some of the coordinates to meet your needs, but this will give you an idea of our procedure.

[code]
MS,4,.5
SA
SC,1

'zero x and y axis
c3

'move to drag knife table offset
jy,23
jz,3

'install the drag knife
pause
jy,31
zy

'zero the z-axis
j2,15,7
c2

'place scrap material on the table and turn on the vacuum.
pause

MS,4,.5
JS,6,1

'set the starting coordinates for test cuts
&X=11.5
&Z=0

'make first test cut
BEGINNING:
JZ,.15
J2,&X,-.25
MZ,&Z
MY,14.5

'test for too deep cut on first try
MSGBOX (DID WE CUT ALL THE WAY THROUGH THE MATERIAL? , YesNoCancel, Check your data!)
IF &MsgAnswer=Yes THEN GOTO WRONG



'increment X and Z and perform new test cut
CUTCYCLE:
&X=&X+.05
&Z=&Z-.002
MZ,.15
J2,&X,-.25
MZ,&Z
MY,14.5

MSGBOX (DID WE CUT ALL THE WAY THROUGH THE MATERIAL? , YesNoCancel, Check your data!)
IF &MsgAnswer=Yes THEN GOTO FINISH

GOTO CUTCYCLE



WRONG:
&X=&X+.05
&Z=&Z+.012
GOTO CUTCYCLE

'zero z axis at new depth and jog home
FINISH:
ZZ
JH
END
[/code]