Need Help!- Clamping work to table

[jeffmorris]

What's the best way of clamping work to table on the CNC machine when cutting out letters/numbers, etc? I'm afraid of using double-sided tape because it'll clog the bits. There's a vacuum table for sanding and routing in the workshop at the program for mentally handicapped people but the CNC machine may not fit on it.

[wyldesyde007]

Originally Posted by jeffmorris What's the best way of clamping work to table on the CNC machine when cutting out letters/numbers, etc? I'm afraid of using double-sided tape because it'll clog the bits. There's a vacuum table for sanding and routing in the workshop at the program for mentally handicapped people but the CNC machine may not fit on it.

vaccum clamping is great but it does require a pretty forcefull vaccum draw to hold everything ridgid. If you are cutting these letters from larger pieces of material you could add "tabs" or "bridges" to keep the parts in place, that would allow you to clamp the entire sheet on the sides machine out your letters then cut the tabs by hand.

[thething84]

depending wot the material is and how thick you could try double sided tape. We have used it for varouse things at work on aluminium. Providing you got some good surface to use it on.

[Cartierusm]

Jeff, I guess thething didn't read your entire post, because he recommended the thing you wanted to avoid. Anyway, wyld has the right idea. A lot of programs have functions to add tabs or webs. What this is, is a way to keep the letters in place during machining. The tab function adds very small tabs to the bottom of the piece and when you're done cutting you can break them with your hands and sand off the flashing in about 1 second. The web though leaves a very minute amount of material at the bottom, basically it doesn't cut all the way through. In your CAM it will ask how thick you want the web to be. Vacuum would be out of the question if you cut different letters all the time. As far as I know you have to have a perfect seal to hold parts down with vacuum. I think it would be a waste of time to trace all the letters and lay down gasketing.

[cuemaker1]

When I cut my parts I have made a baseplate with various t-nuts on the back side. I made a few aluminum straps bent to different shapes for different thicknesses of wood and clamp them down by a hole drilled in the aluminum and a screw into the t-nut. I mostly use .160 thickness wood or other material and then cut to a depth of .120, thereby keeping the pieces in tact. I then sand off the back of the material in a drum sander to relieve the pieces. Some of the pieces I cut are as small as .125 x .1, then as big as 12 x 12, so it works for me. I made the baseplate of flat plywood and drilled the holes every 2 inches in all directions for any size material, of course I only have a 24 x 19 techno isel so it limits me on doing anything too large. I also do tabs at times with the bigger pieces. (farmer engineering...)

[jeffmorris]

Included in the plans from Solsylva is the one for a large 27 X 64 belt drive machine. Its table has "T" slots made by ripping MDF board into 2-1/2" and 3-1/2" strips. Could the table be made for the 17 X 20 overhead leadscrew machine?

[jeffmorris]

Will toggle clamps work? If so, which one - horizontal or vertical? I made a 21" X 12" sign on my CNC router but the board was slightly warped and the bit didn't clear the board while moving from one letter to other. I used other boards and "C" clamps to hold the board in place around its edges. Would mounting two pieces of wood along the bottom and left of the base and use other pieces of wood with clamps along top and right of the base to hold the board in place work? What about T-Track?