101 .060 x .060 slots in Ultra-High Molecular Weight Polyethylene

[cwaugs]

I need to cut 101 .060 wide x .060 deep slots spaced .125 apart, in UHMW Polyethylene in one pass. I plan on purchasing 101 slitting saws then spacing them .125 apart with some sort of spacers on an arbor to chuck in my small logan lathe with the other end of the arbor stabilized with the tailstock. Anybody ever tried such a crazy feat? Time and accuracy in slot placement is the main two concerns. My CNC router takes too long per piece. Thanks in advance for your time Sirs!

[cam1]

Hi:
A few comments or points to ponder:
1) how dou you plan on fixturing the workpiece? Is the x slide wide and stiff enough?
2) how are you goin to control the depth of the slots?
3) Will the arbor be ridgid eneough for the cutting forces?

My opinion is that it's going to be a mess.

My experience with HDMW is that its as slippery as teflon, and really gummy. The brand new 3/8 HSS mill I was using just slid all over the material (I was trying to machine a 1/2 blind slot, using coolant and modest speeds and feeds). The deburring tool was no easier to use either....

regards

[cwaugs]

I was gong to mount a piece of stock the width of the piece onto the crossfeed and have support at both ends mounted on the bed that would be up tight enough to allow it to slide. I need 7" of travel for the piece. The depth of the slots would be determined by the thickness of the stock and the piece of poly, I know, crude, but after it is setup doing a bunch of them might be feasible. I would hope to find a relatively hard piece for the arbour and cut slow to prevent it from bending. I agree a mess it might be but if there was a chance it would work it would save a ton o time. Thanks again Wayne

[Geof]

Not a totally crazy idea.

Are you doing a lot of these?

The lathe idea could work but there is a but.

Your slitting saws are going to be spaced 0.06" by using spacers. (How is that for an obvious statement? Wonderful how smart one can be with the help of a glass of wine.)

Seriously; your arbor will have on it 101 slitting saws separated by 100 spacers with two end flanges and a nut on one end. The slitting saws are no doubt parallel to within fractions of a thou. It is essential that your spacer washers are similarly parallel. If any of the spacers are not perfectly parallel (I know perfection is impossible but you are going to need it here.) when you tighten the nut and compress everything any out of parallelism in the spacers is coverted into a bend in the shaft.

I harken back to the good old days of setting up horizontal milling machines with spacers and cutters on a long arbor. It was possible to introduce a bend in the arbor because a spacer had a dab of grease on one side. The grease would not totally squeeze out and the minuscule residue was the same as an out of parallel end on the spacer.

I suspect if extreme accuracy is required you may need a dedicated machine with fewer cutters making multiple passes.