Re: [CAD_CAM_EDM_DRO] Metric measurements.

Thanks Tom
That sounds a useful tip. I will experiment and get back to you with progress.

Keith

At 01:04 21/07/2005, you wrote:

>Hello Keith,
>
>Some Gcode executing software uses G70 and G71 and others use G20 and
>G21 to indicate that the program length units are inches or millimeters.
>Check your owners manual or just try them and see which ones do not give
>error messages.
>
>At the top of your Gcode file, or at least before any length units can
>be misinterpreted, insert G20 or G70 to indicate that the length units
>are to be performed as inches. Use G21 or G71 to indicate that the
>length units are millimeters.
>
>You can also change units within the program. You might millimeters for
>most of your program but have some subroutine that uses inches. Just
>make sure to insert G20, G21, G70 or G71 to tell the Gcode interpreter
>that the length units have changed.
>
>In the absence of these commands the Gcode interpreter will assume that
>the length units are whatever your defaults are set for or whatever was
>last used on a job. it appears that your default is inches.
>
>I ALWAYS use one of these codes near the start of my program since I
>might use either on any job and can never be sure how my last job left
>off.
>
>Tom Hubin
>thubin@...
>
>***************************
>
>kbucklitch wrote:
> >
> > Hi folks
> >
> > This is my first posting to the group, in the hope that someone will
> > be able to assist me.
> >
> > I create my CAD drawings with TurboCAD. For several years, I have
> > produced my drawings using metric (mm) measurements. Before I
> > started experimenting with CNC, if I printed the drawing full size,
> > then it was printed almost exactly the size of the item (within the
> > accuracy of the printer).
> >
> > To use the drawing to create a toolpath for the CNC cutter, I export
> > the drawing initially as a .dxf file. I have then converted the
> > file to G-code using two programs - KCam or Simsoft Mach 2. Both
> > of these will produce a G-Code script. I then use the software to
> > drive the CNC controller. At present, because I am driving my CNC
> > control with KCam on an old laptop under Windows 98 (Mach 2 requires
> > WinXP.) However, I have found a problem. The CNC driver seems to
> > work in imperial units (inches). Hence, a component that should be
> > say 20mm long, becomes 20 inches long. This is a little difficult
> > on a milling machine which only has around 12" of travel.
> >
> > In the KCAm Setup/Table Setup menu, it asks if you want (are using?)
> > imperial or metric measurements. However, choosing metric in this
> > dialogue box does not appear to make any difference to the finished
> > size of the article.
> >
> > Does anyone with experience of these programs - Mach 2 or KCam know
> > how I can set them up so as to convert metric .dxf files to metric
> > machine codes?
> >
> > Thanks
> >
> > Keith
> >
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>davemucha@... [Moderators]
>URL to this group: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO
>
>OFF Topic POSTS: General Machining
>If you wish to post on unlimited OT subjects
>goto: aol://5863:126/rec.crafts.metalworking or go thru Google.com to
>reach it if you have trouble.
>http://www.metalworking.com/news_servers.html
>
>http://groups.yahoo.com/group/jobshophomeshop I consider this to be a
>sister site to the CCED group, as many of the same members are there, for
>OT subjects, that are not allowed on the CCED list.
>
>NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY POSTING
>THEM. DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........
>bill
>List Mom
>List Owner
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>
>Yahoo! Groups Links
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