low cost,long axis plastic cutting

[threeninethree]

Hi

So Ive been lurking for a while pouring over posts here and other sites.
What I need to do is build a machine that can cut out ski and snowboard shapes
in plastic base material (1.2mm thick). The cutting area would have to be no less than 80" X 24". The z axis isnt that critical maybe 3-4".

I was looking at Crankorgans plans (Morph or Phoenix) that utilize the dremel, and the fact that I dont need a burly machine. His machines use a lead screw for power transmission, and from looking over many posts accuracy may be an issue if I was to expand the morph or the Phoenix.

Is there a way to overcome this by use of Acme rod or incorporating a rack and pinion? Any insight into my dilemma would be appreciated, and anyone elso out there who has built the Morph ect.


Thanks,
Matt

[ger21]

The crankorgans are not suitable for that length of machine. Look at www.cncrouterparts.com and www.finelineautomation for rack and pinion drive and other parts.

[Jesse B]

Acme rods that long will have some serious whip to them. R&P is the way to go, and either of those stores will hook you up with what you need.

[CarbonKevin]

You're planning on cutting base for up to 200 cm skis? Starting up your own race company, by any chance?

Two things you should consider, since all you're cutting is P-Tex.

1) A light duty spindle like a dremel probably won't give you a very good edge finish. Consider a tangential knife instead. Or better yet, come up with a dual knife system where the stepper's input drives the two knives in opposite directions to each other, so you can cut both sides of the base at once.

2) You could save a serious amount of money skipping the long-travel X axis, and instead developing a very accurate feeder/puller system to draw the P-Tex through the machine. If you're using the dual knives mentioned above, it would literally be one pass from start to finish.

[threeninethree]

No not a race company, just a small ski and snowboard company. I already have my pneumatic press and molds ect.

The idea of a feeder/puller system sounds intriguing, you may be on to something! Along the same way a thickness planer feeds with rollers and having dual knives instead of spinning planer blades between them.

Would developing something like this be huge money? Are there any knives you know of in particular?

[CarbonKevin]

Originally Posted by threeninethree No not a race company, just a small ski and snowboard company. I already have my pneumatic press and molds ect. The idea of a feeder/puller system sounds intriguing, you may be on to something! Along the same way a thickness planer feeds with rollers and having dual knives instead of spinning planer blades between them. Would developing something like this be huge money? Are there any knives you know of in particular?

The thing that I thought of was CNC textile cutters...if they can be made to cut through something tough like carbon fiber prepreg, I'm sure a knife for P-tex can be made to work. The blades they use for Carbon are carbide, and easily replaceable. That should work for you.

[RomanLini]

If you are setting up for small scale manufacture you are probably better off paying a local waterjet firm to cut the shapes for you, which will be quite cheap.

Then the money and time you would have needed to build a cnc setup can go into other areas like parts of the manufacturing that you CAN'T cheaply farm out.