RE: [CAD_CAM_EDM_DRO] Re: Metric measurements and KCam

Hi folks

Report back time following your suggestions re getting the controller to
respond to metric .dxf files.

1. Re converting the drawing units to imperial. This works, and is simple
to do with the CAD software. The machined parts come out to the correct
size, but I would prefer not to have to do this step if I could avoid
it. However, in the light of the following, it seems the way to go at present.

2. Inputting the G70/G71 codes. Tried this, but nothing changed. I
subsequently found that KCam does not (according to the help pages)
actually support G70/G71, which probably explains why there was no change
in the distances travelled.

3. Presently, I am restricted to using KCam, as my old laptop only has
enough power to run Windows 98, being a P166 machine with only 32M of
RAM. Mach 2 requires Windows XP to run.

So, I shall have to stick to converting the dimensions in the CAD program
before translating the .dxf file to Gcode. Thanks for the suggestions though.

Now, another query.

Does anyone else use KCam? The reason for the question is that I am still
evaluating the software, and find that with some dxf files, when it
converts it to Gcode, there is a cluster of extraneous cut paths usually at
the 0,0 position. Is this a bug in the software, or is it only a problem
with an unregistered copy? I hesitate to register and pay for a license if
the software is not going to work satisfactorily. I have tried emailing
KCam for support, but get no response. The implication is that one must
register first, but if the software is not going to work properly, what is
the point of registering?

Any comments?

Keith


At 21:10 21/07/2005, you wrote:

> Change your code to have the proper G70/G71 or G20/G21 in it, which will
>tell the controller to interpret the units in the code as either inches or
>millimeters.
>
>Andy Wander
>
>-----Original Message-----
>From: Keith Bucklitch
>To: CAD_CAM_EDM_DRO@yahoogroups.com
>Sent: 7/21/2005 3:16 PM
>Subject: Re: [CAD_CAM_EDM_DRO] Re: Metric measurements.
>
>Hi Dave
>Thanks for the suggestions.
>I have worked around the problem by changing the measurement units from
>metric to imperial before coding the .dxf file, but would prefer to be
>able
>to feed the original metric units directly to the controller, hence my
>request.
>
>I will have a look at the idea of amending the CNC to run as you
>suggest. Not immediately sure how to go about that, so I shall have to
>do
>some reading. My mill is a Taig /Peatol Micromill which has the
>leadscrews
>on a 20tpi pitch (50 thou"). The interface is in half-step mode, with
>the
>steppers having therefore 400 pulses revolution. I calculate that as
>8000
>pulses per inch of travel. Correct?
>
>So, to get 1mm of travel, should I set the interface to give me
>8000/25.4 =
>314.96 steps/mm. In fact, we probably need to be more accurate in the
>conversion than that, what is the correct inch to mm ratio?
>
>Surely, the control software ought to be able to do that automatically.
>It
>asks what units I am working in, imperial or metric, so why does it not
>do
>the conversion?
>
>Keith
>
>At 23:07 20/07/2005, you wrote:
>
> >One possibility would be to change the unit in your CAD before making
> >the DXF. My CAD allows me to jump back and forth at will.
> >
> >But, another problem may be that you have your CNC set to run in
> >inches. a 5 TPI leadscrew with 1,000 steps per inch will move 1,000
> >steps per "ONE UNT"
> >
> >If you set the driver so a 'unit' is a mm, then moving one 'unit'
> >would be 25.4 steps and not 1,000 steps.
> >
> >Dave
> >
> >
> >
> >--- In CAD_CAM_EDM_DRO@yahoogroups.com, "kbucklitch"
> ><keith.bucklitch@w...> 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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>Addresses:
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>[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
>
>
>Yahoo! Groups Links
>
>
>
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>
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>Addresses:
>FAQ: http://www.ktmarketing.com/faq.html
>FILES: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/files/
>Post Messages: CAD_CAM_EDM_DRO@yahoogroups.com
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>Moderator: pentam@... indigo_red@...
>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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>
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