Re: [CAD_CAM_EDM_DRO] USB and ncPOD system

Stephen Wille Padnos wrote:

> Lester Caine wrote:
>
>> 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.
>>
>>
> Well, with the exception of turning it backwards (something we've
> discussed vefore, but not implemented yet), you can do this with EMC2.
> You can unplug the spindle while cutting a thread, and the tool will
> stop (in time with the spindle slowdown, of course), then you can turn
> the spindle by hand, and the tool will move along the path, synchronized
> with your new manual spindle. ;) We actually did this last year at the
> workshop, because we wondered the same thing.

So currently if you 'rocked' the chuck back and forth you would loose
position? I can't see that there should be any problem running the spindle in
reverse - in fact the discussion was when using an 'electronic gearbox' you
would switch the spindle to reverse after withdrawing the tool in order to
move back to the start point and maintain accurate sync.

> Of course, this can't be done with just an index pulse, as you pointed out.

But the index pulse IS essential if you move the tool back without reversing
the spindle as you need it to re-establish synchronisation again when
re-starting the cut.

--
Lester Caine - G8HFL
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