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70081Re: [Bulk] RE: [mach1mach2cnc] BackLash.. Finally.!! :)

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  • Dave
    Mar 1, 2007
      I always thought that climb milling was to be reserved for hogging with
      rough milling cutters and such. And that conventional milling was the
      best approach for a smooth finish. If that is the case, then who would
      really care about backlash compensation when climb milling since it's a
      roughing operation anyway unless the machine had a tremendous amount of
      backlash?
      Am I wrong about that?
      Dave

      Mark Vaughan wrote:

      > I think about it from my manual mill which has loads of backlash.
      >
      > Conventional mill and you take up the slack before you make contact.
      >
      > Climb mill and I have to tighten the jibs and feed reel slow to stop the
      > cutter sucking the workpiece in with a grunch as it snaps up the backlash.
      >
      > All this applies to backlash compensation, you won't be able to stop the
      > cutter pulling the workpiece in on climb milling, but it will effect where
      > the cut ends.
      >
      > May just be an issue that compensation cannot be used when climb milling.
      >
      > Dr. Mark Vaughan Ph'D. B.Eng. M0VAU
      >
      > Managing Director
      >
      > Vaughan Industries Ltd, reg in UK no 2561068
      >
      > Water Care Technology Ltd, reg in UK no 4129351
      >
      > Addr Unit3, Sydney House, Blackwater, Truro, Cornwall, TR4 8HH, UK.
      > Phone/Fax 44 1872 561288
      >
      > _____
      >
      > From: mach1mach2cnc@yahoogroups.com
      > <mailto:mach1mach2cnc%40yahoogroups.com>
      > [mailto:mach1mach2cnc@yahoogroups.com
      > <mailto:mach1mach2cnc%40yahoogroups.com>]
      > On Behalf Of art
      > Sent: 01 March 2007 20:06
      > To: mach1mach2cnc@yahoogroups.com <mailto:mach1mach2cnc%40yahoogroups.com>
      > Subject: Re: [Bulk] RE: [mach1mach2cnc] BackLash.. Finally.!! :)
      >
      > Hi Mark:
      >
      > Hmm, I hadnt really though of any connection to climb milling.. Ill
      > keep my
      > eye on that
      > and give it some thought. Originally, I had planned on making LCam do the
      > backlash with true movements, but it really complicates arcs, as they
      > become
      >
      > parabolas, not a good thing..
      >
      > Thanks,
      > Art
      > www.artofcnc.ca
      >
      > Videos And Support Forums http://www.machsupp
      > <http://www.machsupport.com <http://www.machsupport.com>>
      > ort.com
      > Users Map: http://www.frappr <http://www.frappr.com/machsupport
      > <http://www.frappr.com/machsupport>>
      > com/machsupport
      > ----- Original Message -----
      > From: Mark Vaughan
      > To: mach1mach2cnc@ <mailto:mach1mach2cnc%40yahoogroups.com>
      > yahoogroups.com
      > Sent: Thursday, March 01, 2007 3:32 PM
      > Subject: RE: [Bulk] RE: [mach1mach2cnc] BackLash.. Finally.!! :)
      >
      > Hi Art
      >
      > Just thinking aloud for a minute, and this may not be viable.
      >
      > For backlash to work correctly it would depend on whether you are
      > conventional or climb milling, this would set whether backlash
      > compensation
      > is required at the start of a cut, or at the end.
      >
      > It's a bit like tool offset compensation and really needs commanding
      > within
      > the Gcode, as you said this starts to make it complex.
      >
      > However you are writing a tool, lazy cam, that might have much of the data
      > available to do this. Either by adjusting the parameters in the right
      > place
      > to do the compensation itself, or since you set climb or conventional
      > milling, then you could also set a Gcode command to set the backlash on in
      > the right place.
      >
      > The other method I suppose is just recommend conventional milling if
      > compensation is switched on.
      >
      > Just a thought anyhow.
      >
      > Regs Mark
      >
      > Dr. Mark Vaughan Ph'D. B.Eng. M0VAU
      >
      > Managing Director
      >
      > Vaughan Industries Ltd, reg in UK no 2561068
      >
      > Water Care Technology Ltd, reg in UK no 4129351
      >
      > Addr Unit3, Sydney House, Blackwater, Truro, Cornwall, TR4 8HH, UK.
      > Phone/Fax 44 1872 561288
      >
      > _____
      >
      > From: mach1mach2cnc@ <mailto:mach1mach2cnc%40yahoogroups.com>
      > yahoogroups.com [mailto:mach1mach2cnc@
      > <mailto:mach1mach2cnc%40yahoogroups.com> yahoogroups.com]
      > On Behalf Of art
      > Sent: 01 March 2007 13:14
      > To: mach1mach2cnc@ <mailto:mach1mach2cnc%40yahoogroups.com>
      > yahoogroups.com
      > Subject: Re: [Bulk] RE: [mach1mach2cnc] BackLash.. Finally.!! :)
      >
      > Mark:
      >
      > Too true. My problem was one of what people expect. Backlash is one of the
      > hardest things to do right. Its taken me 3 years to get to that spot
      > in the
      > driver.
      > Its important to me to keep it in the driver, I dont want comp in the
      > application, too much complexity.. The old backlash caused great problems
      > for some, and some expect seamless operation with backlash.. THisis
      > about as
      > close as I can get...so far anyway..
      >
      > Thanks,
      > Art
      > www.artofcnc.ca
      >
      > Videos And Support Forums http://www.machsupp <http://www.machsupp
      > <http://www.machsupport.com <http://www.machsupport.com>> ort.com>
      > ort.com
      > Users Map: http://www.frappr <http://www.frappr
      > <http://www.frappr.com/machsupport
      > <http://www.frappr.com/machsupport>> com/machsupport>
      > com/machsupport
      > ----- Original Message -----
      > From: Mark Vaughan
      > To: mach1mach2cnc@ <mailto:mach1mach2cnc%40yahoogroups.com>
      > yahoogroups.com
      > Sent: Thursday, March 01, 2007 5:17 AM
      > Subject: RE: [Bulk] RE: [mach1mach2cnc] BackLash.. Finally.!! :)
      >
      > The trouble with all this backlash compensation is backlash is play in
      > your
      > system.
      >
      > Whether compensation is, or is not required depends on the direction of
      > cutting force, whether you are climb or conventional milling.
      >
      > Fine on a lathe where load is normally in the same direction.
      >
      > Because mach offers backlash compensation many diy users will think
      > it's OK
      > to build a machine with half an inch of backlash and mach will take
      > care of
      > it.
      >
      > We need to all be very careful what we understand can and cannot be done
      > with Art's backlash system.
      >
      > There is no substitute here for tight screws. (No pun intended).
      >
      > Dr. Mark Vaughan Ph'D. B.Eng. M0VAU
      >
      > Managing Director
      >
      > Vaughan Industries Ltd, reg in UK no 2561068
      >
      > Water Care Technology Ltd, reg in UK no 4129351
      >
      > Addr Unit3, Sydney House, Blackwater, Truro, Cornwall, TR4 8HH, UK.
      > Phone/Fax 44 1872 561288
      >
      > _____
      >
      > From: mach1mach2cnc@ <mailto:mach1mach2cnc%40yahoogroups.com>
      > yahoogroups.com [mailto:mach1mach2cnc@
      > <mailto:mach1mach2cnc%40yahoogroups.com> yahoogroups.com]
      > On Behalf Of Rich Crook
      > Sent: 01 March 2007 08:08
      > To: mach1mach2cnc@ <mailto:mach1mach2cnc%40yahoogroups.com>
      > yahoogroups.com
      > Subject: Re: [Bulk] RE: [mach1mach2cnc] BackLash.. Finally.!! :)
      >
      > Umm... I think you've got that backwards.
      > 0.0001 mm is *one tenth* of a micron! A micron is a thousandth of a
      > mm, or .00003937" (just shy of 4 ten thousandths).
      > I'm pretty sure he meant .0001"
      >
      > = Rich =
      >
      > >Art,
      > >Holy shit, 0.0001mm is about 4 microns! Did you have to pawn your
      > first and
      > >second born for your glass scales? Are you sure you don't mean 0.0001"?
      > >
      > >Andrey
      >
      > >Hi Andy:
      > >
      > >According to my glass scales, the backlash is exact to .0001mm on my
      > >system.
      > >Thats about as exact as my system can handle...
      > >
      > >Thanks,
      > >Art
      > >www.artofcnc.ca
      >
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