Machsupport Forum

G-Code, CAD, and CAM => G-Code, CAD, and CAM discussions => Topic started by: harryn on October 31, 2007, 03:58:46 PM

Title: Going from Rhino 3D cad to G code for Mach III question
Post by: harryn on October 31, 2007, 03:58:46 PM

Hi

I am building up a DIY CNC router which will be run from Mach III.  I do not have ANY CAD programs or experience, and am not ready to take this part on right now.  I am also new to G code.  Wow - sounds pretty lame when I spell it all out.

Anyway, a guy I know would like to take his 3D Rhino (cad ?) drawings (true 3D shapes, not 2.5) and have me cut them out in foam.  I told him that he should buy a copy of Mach III as well, import the CAD file to Mach III, and send the resulting G code to me to run on my cnc router.  I assumed I can provide a copy of my tool configuration information to him, and his exported G code would work on my router.

Now that I am reading a bit more about it, I am thinking that this advice is not sufficient - perhaps wrong.  After searching through the topics here and on cnczone, it seems that the steps are really more like:

a) Draw in Rhino CAD
b) Convert from CAD to CAM using Rhino CAM or similar
c) Post processor - no idea what that is ?
d) Have him import into Mach III at his site
e) Email the file to me for running
f) Run on my machine using Mach III

Is this right ?

It seems like perhaps Meshcam is easier ?


I tried searching and reading about this topic, but I am still unsure of how to go from drawing to part.

Thanks

HarryN

Title: Re: Going from Rhino 3D cad to G code for Mach III question
Post by: Graham Waterworth on November 03, 2007, 02:44:45 PM

Hi Harry,

Producing G-code in most cases takes 3 steps, sometimes 4 steps.

3 step method :-

1. You draw the part in a CAM system. It can be a 2D or 3D system

2. Create tool paths. This is where you tell the system what tools to use on what part of the job.

3. Post process it into G-code,  the post processor is a way of converting the internal tool paths of the CAM system into a g-code file format that a particular controller needs. E.g. Mach 3

On the 4 step systems, the part is drawn in a CAD system and then imported into the CAM system. The import format can be DXF for 2D and IGES for 3D. Then it is as the 3 step system.

Graham.

Title: Re: Going from Rhino 3D cad to G code for Mach III question
Post by: harryn on November 05, 2007, 11:15:17 AM

Thank you for the information Graham.

An alternative file format I was advised on was:
- Create 3 D drawing in Rhino
- Save the Rhino drawing in STL format
- Import te STL format file into Mesh CAM
- Create the tool paths / G code in MeshCAM, then view them in CUT VIEW
- Import the G code into Mach

Is there any particular advantage of using IGES vs STL formats for exporting the Rhino 3 D cad files ?

BTW, I have read through the Mach III on-line manual 1 X through now - what an amazing amount of programming and feature depth.