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Author Topic: Can't generate G code for this simple dxf...  (Read 2952 times)

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Can't generate G code for this simple dxf...
« on: March 20, 2016, 07:11:29 PM »
When I first learned about Mach 3 I was excited.  It looked like I would be able to put my experience with computers and programming to use, so I put all this time and effort into converting this old Bridgeport CNC to Mach 3 and I can't manage to convert the simple attached dxf figure (which I drew and generated with Inventor in just a few minutes) to G code for engraving onto a surface.  LazyCam won't do it and the Ace Converter program I downloaded won't do it.  The whole idea behind becoming Mach 3 capable was so I wouldn't have to key in G code a line at a time.  What is the solution?

Offline ger21

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Re: Can't generate G code for this simple dxf...
« Reply #1 on: March 20, 2016, 08:10:17 PM »
Post the .dxf and I'll tell you why.
Does inventor give you an option of saving as v12 dxf? If so, try that.
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html
Re: Can't generate G code for this simple dxf...
« Reply #2 on: March 20, 2016, 09:49:14 PM »
It saves as an Autocad dxf.  I can save in Autocad 2010, 2007, 2004, 2000 or R12.  I think the problem is the ellipses.  I tried saving a dxf of just one of the three ellipses and couldn't get it to translate.  Probably too many points for the converters to handle.  I can approximate the ellipses pretty closely with circular arcs of the correct size chained together, but what a PITA of a way to do this.

Hmmmm.  You got me thinking.  I saved it out as an R12 dxf and it converted.  It looks like about 130 point straight line approximation of the ellipse, but that is close enough for my purposes.  I can get it from here.  Thanks.

Offline ger21

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Re: Can't generate G code for this simple dxf...
« Reply #3 on: March 20, 2016, 09:52:14 PM »
LazyCAM and ACE can not read ellipses.

R12 does not support ellipses or splines, and converts them to polylines on export.
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html
Re: Can't generate G code for this simple dxf...
« Reply #4 on: March 20, 2016, 10:07:12 PM »
Is there a better converter that will do ellipses for a retired guy on a fixed income?

Offline ger21

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Re: Can't generate G code for this simple dxf...
« Reply #5 on: March 20, 2016, 10:17:54 PM »
I don't use ellipses, so I'm not sure. I draw in AutoCAD, and it has an option to use arcs for ellipses.

Ace is probably over 10 years old, and LazyCAM not far behind it. Something more modern probably does, but I'm not sure at what cost.
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html
Re: Can't generate G code for this simple dxf...
« Reply #6 on: March 21, 2016, 02:29:11 PM »
Why don't you just explode the object?

I find that when I export to DXF the object is a 3d object and sheetcam does not like it, hence I will explode it.

Provide a copy of what you have created and let me have a look at it.

What depth do you want it engraved + with what tool?

Is it a v-carving tool?

What are you machining it in (did you have a feed speed and a spindle speed in mind....)
Rob

Albert Einstein ― “If you can't explain it to a six year old, you don't understand it yourself.”

Offline ger21

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Re: Can't generate G code for this simple dxf...
« Reply #7 on: March 21, 2016, 03:03:07 PM »
Can you explode a drawing from Inventor? I wouldn't think so.
In AutoCAD, you can't explode an ellipse.
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html
Re: Can't generate G code for this simple dxf...
« Reply #8 on: March 21, 2016, 03:19:48 PM »
From inventor, export the part to dxf, then explode the dxf
It may be polylines that the gcode generating software is not happy with, not the ellipse object itself.

I'll draw one later and see what sheetcam does (kids 2 bed first...)
Rob

Albert Einstein ― “If you can't explain it to a six year old, you don't understand it yourself.”

Offline ger21

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Re: Can't generate G code for this simple dxf...
« Reply #9 on: March 21, 2016, 04:29:57 PM »
What  are you using to explode the .dxf after you export it?
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html