New Machine Build- 3 axis, NC code run machine to cut Plastic material

[karan_kulkarni]

Looking for help in building a machine, which has its input from a computer in NC code. The machine is used to cut out stencils of plastic material(ESD material), in shapes of: squares, rectangles, triangles, circles.

The head that cuts, must move in X,Y and Z axis and is made of a spindle or a carbide tip (yet to decide).

Suggestions and opinions are welcome.

[ger21]

Look around in this forum and you'll find hundreds of similar machines. Although most are made to cut wood, cutting plastic is very similar.

[CarbonKevin]

If you use a spindle, you won't be able to cut polygons correctly - you'll have radiused corners. You can minimize this by using a very fine bit, but then you won't be able to cut as quickly.

If this is a high production item, get a die set made to punch the stencil from rough cut blanks of ESD.

If you need to be able to cut various arrangements of shapes - different stencils - a turret punch would work well because you can change the configuration.

If you're making lots of different stencils, a tangental knife is what I would do. In that situation, you could build a 3-axis machine similar to a vinyl cutter which would suit your needs well.

The only time I'd consider a router would be if the material is very thick, or too brittle to punch.

[karan_kulkarni]

Thank you CarbonKevin!

Well looks like I need a little bit of everything.

Some more info on the machine :

The material is in the range of thickness: 3mm to 10mm
Work area, where the plastic material is placed : 2feet by 2feet
Accuracy: +/- 1mil
No two stencils are similar, each stencil has varying shapes to be cut.
Speed: as fast as possible.

I do need radiused corners, so a spindle should help in this case.

[CarbonKevin]

Originally Posted by karan_kulkarni Thank you CarbonKevin! Well looks like I need a little bit of everything. Some more info on the machine : The material is in the range of thickness: 3mm to 10mm Work area, where the plastic material is placed : 2feet by 2feet Accuracy: +/- 1mil No two stencils are similar, each stencil has varying shapes to be cut. Speed: as fast as possible. I do need radiused corners, so a spindle should help in this case.

What radius do you want in the corners?

I'm not very well informed on tangential cutters, but 10mm seems awful thick to cut through, and I can't imagine multiple passes being a good thing, either.

What kind of plastic will you be using?

[karan_kulkarni]

The radius is not an important factor, just that the edges should be curved and not sharp.

The material used is ESD - a plastic material which is very flexible and bends easily.

[mll]

Hey Carbon Kevin

I am looking for a tangental knife to attach to my CNC router to cut foam do you know where I can buy one.

Thanks
Mike

[jasminder]

Originally Posted by karan_kulkarni Looking for help in building a machine, which has its input from a computer in NC code. The machine is used to cut out stencils of plastic material(ESD material), in shapes of: squares, rectangles, triangles, circles. The head that cuts, must move in X,Y and Z axis and is made of a spindle or a carbide tip (yet to decide). Suggestions and opinions are welcome.

Hi karan,
you can use any high speed spindle with 1mm or more sized carbide to cut depending upon the thickness of plastic. The accuracy you are trying to achive can be easily achived by using 16mm balscrews and 12/15 mm thk linears.

best of luck for the build.
jasminder singh

[CarbonKevin]

Originally Posted by mll Hey Carbon Kevin I am looking for a tangental knife to attach to my CNC router to cut foam do you know where I can buy one. Thanks Mike

Hey Mike,

What kind of foam are you cutting? How thick?

I don't have a clue where you'd buy something like this...from what I've gathered, there's static knives, or ones that oscillate up and down to do a bit of a sawing action to help the cutting process.

This site has a good writeup on a static knife a guy made to cut vinyl stickers...

http://www.cuttingedgecnc.com/vinyl.htm

I've been thinking about this for awhile, someday I might get around to designing something that will fit in to my router's 1/4" collet, so it can use the bearings of the router rather than needing bearings of it's own to rotate freely with the cuts.

Whether or not that would work for you, or if you'd need an oscillating unit, I don't know.

[CarveOne]

Do a Goggle search on "CNC tangential knife" and you'll find some links to look at. These are for foam board and cardboard, not for thick foam blocks.

CarveOne