Slot drill not, umm, slotting!

[rich_cree]

Hi folks

I've got a bit of an issue with my Tag CNC conversion. It seems to do pretty much everything bar plunging a slot drill into material. The Z axis misses steps when I do this. For instance, I am trying to pocket out an 1/8" piece of aluminium. In areas which are already partially pocketed and I'm just enlargin the pocket then it works perfectly. In area where I am trying to create a new pocket, it does not cut deep enough, then when the cut is done, the Z has lost position and is high, suggesting that the machine has been unable to plunge into the material.

The tool I'm using is a 2 flute slot drill, is there such a thing as a slot drill that can't be plunged?

Any other ideas?

Thanks!

[jeffrey001]

Try to use ramping with the Z-

A slot drill is not real good at drilling because one lip is longer than the other, unless you have a rigid maching, use ramping or drill a hole before using the slot drill.

Jeff

[davereagan]

Drill a starter hole. Even center cutting endmills are not happy plunging and the thrust is more than you'd expect. If you don't want to drill, try plunging at .0002" per revolution and see if you don't miss steps.