Re: [CAD_CAM_EDM_DRO] USB and ncPOD system

Lester Caine wrote:

> Stephen Wille Padnos wrote:
>
>>Andy Wander wrote:
>>
>>
>>>Steve:
>>>
>>>Mach3 works great for threading with a single pulse per rev.
>>>
>>
>>Ah - the requirement was for EMC2, not in general. My suspicion is that
>>the single pulse method will not work well in situations: where you're
>>taking heavy cuts relative to the spindle mass/power. Also, if the
>>material removal rate is variable (as it could be for a tapered thread
>>or something like that), it can cause issues.
>>
>>We may get a chance to test some single-index threading at CNC Workshop
>>this year - I'll certainly be interested in seeing just how "good
>>enough" that is.
>
>
> My thought had been - what happens when you turn the spindle by hand.
> Impossible with a single pulse, but given a high res encoder you would get the
> tool moving back and forth as you rock the chuck given the ideal interface
> hardware :)
> Mach3 can't do that, and I doubt EMC2 could ( unless you can leave it IN a
> screw cutting pass), but all the calculations say that it is quite practical.
> So the next step is some of the fine detail.
>

The current version of EMC2 does not accomodate reversing the
spindle. The feed stops if you turn the spindle backwards.
This code was designed specifically for single-point tooling on
a lathe. It is planned to extend it for rigid tapping, and
there it will have to reverse the Z feed when the spindle begins
to turn backwards.

But, I have done this in one direction, and the Z feed
absolutely comes to a dead stop and waits for you to move the
spindle forward some more. You could actually cut a thread
turning the spindle by hand, varying the spindle speed as much
as you want. It really does work, and kind of seems like magic
the first time you do it!

Jon