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View Full Version : How to generate Lathe GCode from a drawing?



Robin2
21-10-2013, 09:24 AM
In the 3D printing world there is software such as slic3r which produces GCode from a suitable 3D drawing of the part to be manufactured.

Is there any equivalent software that creates GCode for a lathe from a drawing (I haven't been able to find any).

Thanks,

...R

Clive S
21-10-2013, 11:14 AM
In the 3D printing world there is software such as slic3r which produces GCode from a suitable 3D drawing of the part to be manufactured.

Is there any equivalent software that creates GCode for a lathe from a drawing (I haven't been able to find any).

Thanks,

...R
If you search for CAM programs like BobCam etc. you will find what you need. ..Clive

FatFreddie
21-10-2013, 11:52 AM
CamBam CNC Software (http://www.cambam.co.uk/)

40 session trial and then will still work for small files - biased towards milling but I've used it for lathe work

Robin2
21-10-2013, 12:20 PM
Thanks. I should have said that I'm looking for software that will run on Linux, not Windows or Mac.

...R

m_c
21-10-2013, 12:31 PM
You'll be struggling to get something that runs on linux.
Lathe CAM doesn't have that many options, let alone ones that will run on linux.

I think CamBam has a linux option, although it's lathe capabilites are pretty limited (lathe only got added within the last couple releases).
The usual options are Lazyturn (it's free - there's a forum on the Machsupport forum) which is fairly limited and not being actively developed (it was written by Art but there wasn't really the demand for it), or Dolphin CADCAM, which is a lot more comprehensive but costs more.
I'm not sure how Bobcam compares.

John S
21-10-2013, 01:42 PM
Thanks. I should have said that I'm looking for software that will run on Linux, not Windows or Mac.

...R

We are not making porridge for one :glee:

Robin2
21-10-2013, 02:04 PM
We are not making porridge for one :glee:

I don't understand?

...R

Robin2
21-10-2013, 08:33 PM
Looks like there is no alternative to DIY.

Over a couple of hours this afternoon I have put together a short JRuby program that will produce GCode from an array of Z,X values that represent the profile (or half cross-section) of the finished piece.

If anyone wants a copy of my code (which is very basic) let me know. (No charge ! )

...R

Robin Hewitt
21-10-2013, 10:19 PM
I don't understand? ...R

Old joke: A Scotsman goes to heaven and is asked if there is anything he would particularly like?

Robin2
21-10-2013, 10:37 PM
Is that because he was only Scotsman in heaven?

Or had it something to do with one of my posts?

...R

Jonathan
21-10-2013, 11:40 PM
Looks like there is no alternative to DIY.

Over a couple of hours this afternoon I have put together a short JRuby program that will produce GCode from an array of Z,X values that represent the profile (or half cross-section) of the finished piece.

If anyone wants a copy of my code (which is very basic) let me know. (No charge ! )

...R

Have you included tool tip radius compensation? If not your code will only be accurate for moves parallel to X and Z, or with very sharp tools with no tip radius.

birchy
22-10-2013, 02:54 AM
Maybe dxf2gcode? I'm going to be using LinuxCNC (cos I'm a Linux geek) and have briefly tried dxf2gcode. Seemed to work OK. Try searching the LinuxCNC wikis and forums as well, the members always seem to be willing to help and will probably suggest other programs.

Robin2
22-10-2013, 10:09 AM
@Jonathan, thanks for the tip !

@birchy - thanks I will look at dfx2gcode

...R

Robin2
22-10-2013, 11:00 AM
@birchy, I've now had a very quick look at dfx2gcode. It seems only to produce code for milling.

Have you used it to generate Gcode for a lathe? If so perhaps you could explain what I need to do.

Thanks

...R

birchy
24-10-2013, 06:37 PM
@Robin: Sorry, I've only done some quick tests on milling machine programs and assumed it would also convert dxf files to lathe gcode. You'll find this an interesting read... LinuxCNC Support Forum :: Topic: lathe programming (1/3) (http://www.linuxcnc.org/index.php/english/forum/31-cad-cam/487-lathe-programming)

Robin2
24-10-2013, 08:39 PM
@birchy, thanks.

I had seen that LinuxCNC link.
The final bit about using Blender got me looking at the internals of some of the data formats. SVG files seem fairly simple and I might experiment with using them as input to my JRuby GCode generating program. But it may actually be simpler to devise a piece of program that would produce a series of short straight lines for an arc.

Truth is I'm at the very beginning and I'm not sure what I will want. The purpose of my enquiry here was to ensure that I'm not re-inventing the wheel because I missed something simple, good and free.

I will probably try to do some milling on the lathe using a vertical slide as the Y axis and (just to make things complex) it will be the Z axis for 3D printing.

...R

m_c
25-10-2013, 12:14 AM
The lack of Lathe CAM options is down to the limited number of CNC lathe owners, and I'd guess the larger majority of those are professional users where paying for good CAM is not a major issue.
There are far more mills and routers than there are lathes, and lathe CAM is alot more complex than standard mill CAM.

One thing that sticks in my mind is Art Fenerty mentioning that writing LazyTurn was essentially a lesson in collision detection. External turning you have to deal with avoiding all the tool edges colliding on the profile, and internal turning you have to deal with the non cutting edge having enough clearance in the bore.

Have you had a read through the main thread about LazyTurn on the Mach forum?
I'm pretty sure that's where Art mentioned alot of the issues he had to work with, and I'm sure it would provide you with a good insight into what's actually needed to get a good lathe CAM.

Robin2
25-10-2013, 10:49 AM
Thanks @m_c.

That LazyTurn thread is verrryyyyyyy loooonnnnnnnnnggggggggggg

I will keep it in mind.

...R

m_c
25-10-2013, 05:04 PM
It is a long thread, but you'll probably find the final half is all about getting it to work/working around issues that never got sorted. I'd concentrate on mainly reading Art's posts. I can remember him mentioning the main issues somewhere, and I'm sure it was in that thread, although it could of just as easily been on the Mach yahoo group, as quite a few of his side projects overspilled on it aswell.

It's a shame he never developed LazyTurn more, but Gearotic Motion is his current project.