Re: [CAD_CAM_EDM_DRO] Re: EMC and lead screw compensation

Gotcha! :)


-----Original Message-----
From: Wally K <cnc4me@...>
To: CAD_CAM_EDM_DRO@egroups.com <CAD_CAM_EDM_DRO@egroups.com>
Date: Wednesday, November 08, 2000 9:53 AM
Subject: [CAD_CAM_EDM_DRO] Re: EMC and lead screw compensation

>Smoke wrote:
>
>> Maybe we should be installing laser positioning devices on the
>machines now
>> to indicate actual backlash "on the fly"? Would that work well
>with ACME
>> screws? That way we could eliminate the use of ball screws
>altogether.
>> This would be ideal for designing new machines....especially
>lathes...where
>> some people want both CNC and Manual capabilities..
>>
>> Smoke
>>
>>
>> >-----release notes-----
>> >7. Added bidirectional lead screw compensation. Files of
>compensation
>> >points look like this (these sample comp values are exaggerated):
>> >
>> >0.000000 0.000000 -0.001279
>> >0.100000 0.098742 0.051632
>> >0.200000 0.171529 0.194216
>> >0.300000 0.292485 0.291030
>> >0.400000 0.439511 0.367981
>> >0.500000 0.451323 0.493962
>> >0.600000 0.618011 0.618044
>> >0.700000 0.669925 0.735979
>> >0.800000 0.798637 0.787879
>> >0.900000 0.889286 0.927685
>> >1.000000 1.007024 0.959853
>> >...
>> >
>> >where the first column is the commanded axis position, the second
>> >column is the measured position (like with a laser) in the forward
>> >direction, and the last column is the measured position in the
>reverse
>> >direction.
>
>
>Wally replys:
>
>Smokie, i could not tell if you were kidding or serious in your
>reply. If you have acme screws and try to circle interpolate a
>circle you get a axis jump at 4 points of the circle from the
>backlash. It is very doubtfull this big jump could be compinsated
>for as the stepper would have to reverse direction faster than the
>table would jump. You Can't make a silk purse out of a sows ear.
>Bridgeports typically have about .03 backlash.
>
>
>Also to put a laser and associated measuring equipment on each axis
>would probably cost much more than the ballscrews would.
>
>
>
>Welcome to CAD_CAM_EDM_DRO@...,an unmoderated list for the

discussion of shop built systems, for CAD, CAM, EDM, and DRO.

>
>Addresses:
>Post message: CAD_CAM_EDM_DRO@egroups.com
>Subscribe: CAD_CAM_EDM_DRO-subscribe@egroups.com
>Unsubscribe: CAD_CAM_EDM_DRO-unsubscribe@egroups.com
>List owner: CAD_CAM_EDM_DRO-owner@egroups.com, wanliker@...
>Moderator: jmelson@... [Moderator]
>URL to this page: http://www.egroups.com/group/CAD_CAM_EDM_DRO
>FAQ: http://www.ktmarketing.com/faq.html
>bill,
>List Manager
>
>
>