cutting gasket material

[JohnCoker]

Can custom gaskets be cut with normal end mills? Perhaps the drag knife would be better, but only for the very thinnest gasket material.

I'm looking at something like this adhesive gasket sheet material (http://www.amazon.com/gp/product/B003VYAXSG/ref=ox_sc_act_title_1?ie=UTF8&psc=1&smid=ATVPDKIKX0DER).

[scottp55]

John,
You sure you want open cell?
Check out Allstars cover gasket. When they were in Maine at Camp last fall I got some samples. Haven't cut yet, but did buy the Onsrud 30degree engraving with the small flat shown here. They finally settled on that bit after a lot of experimentation and liked it the best so they sell it.
Recommend maybe buying from someone who ships first class as shipping KILLS from them as it's UPS only.(sorry George).
http://allstaradhesives.com/cart/product_detail/cover_gasket_router_bit/44

[Brady Watson]

A drag knife would be best for that. The only way to get clean cuts using a rotary tool is if you are running super high RPM - as in 60k+. They don't have a lot of torque, but something like a Turbo Carver or dental drill etc that run at 400k via air would be ideal for this. Clamp it on your Z and run it like a 2nd spindle. With a diamond bit, it will pretty much cut anything.

-B

[Rick W]

John,

I've cut gasket material with good success by sandwiching it between 2 other substrates. In my case plexiglas with an 1/4" end mill.

Should clarify that only the inside holes and locations, the exterior was cut with a knife. In my case the outside wasn't that important.

I cut cork for 3 carbs on my boat.

Rik

[donek]

Can custom gaskets be cut with normal end mills? Perhaps the drag knife would be better, but only for the very thinnest gasket material.

I'm looking at something like this adhesive gasket sheet material (http://www.amazon.com/gp/product/B003VYAXSG/ref=ox_sc_act_title_1?ie=UTF8&psc=1&smid=ATVPDKIKX0DER).

You can cut up to 1/4in thick material with our drag knife. Gaskets are no problem. We even have people cutting kevlar. Go to: www.donektools.com for details. You can even get it from the shopbot store: http://store.shopbottools.com/search?type=product&q=donek

[pappybaynes]

John,
You sure you want open cell?
Check out Allstars cover gasket. When they were in Maine at Camp last fall I got some samples. Haven't cut yet, but did buy the Onsrud 30degree engraving with the small flat shown here. They finally settled on that bit after a lot of experimentation and liked it the best so they sell it.
Recommend maybe buying from someone who ships first class as shipping KILLS from them as it's UPS only.(sorry George).
http://allstaradhesives.com/cart/product_detail/cover_gasket_router_bit/44
I used the Onsrud 30 degree bit for my full table (4x8) gasket to cut cut 248 coasters...worked great!
Dick

[gbradley]

John

I am like the kid in the candy store as far as the gasket goes. I have cut our gasket with the engraving tool and got a pretty good edge (the cheaper way to go), and I also cut the gasket with the drag knife clean edges. nobody sees the fixture with the gasket on it it is the finished product that matters. What do you want to cut?

[JohnCoker]

I assume the drag knives work without the spindle turning. Is there a way to leave the spindle off for a cut?

[donek]

I assume the drag knives work without the spindle turning. Is there a way to leave the spindle off for a cut?

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.

[jerry_stanek]

When I use the drag knife or plotter pen I remove the so1,1 and also don't turn the VFD on

[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.

25845

25846

25847

[gbradley]

Here are some pictures of cutting some fixture gasket.

25863

25864

[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.



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