Modeling tolerance ??

[dkmc]

I am designing in Alibre and exporting to a CAM program to generate G code for a CNC Lathe.
Having problems with radius's that are not accurate enough, or are a series of facets. This is causing the CAM software to
use many,many radius moves instead of just one or two.


Here is what someone that is not familiar with Alibre suggested:

make sure you model with a low modeling tolerance. A high tolerance looks good on the screen, but makes for a hell of a time when trying to export to other systems or using CAM software.

My question is, where do I find those settings and how do I set them to minimal (.0001 inch) tolerance?

BTW....I was exporting IGES files but it's suggested I use STEP or another format.
Which is best and most accurate for this?

thanks
dan k

 

[Anonymous]

Before making a suggestion I have to tell you that I really don't use Solid Models on 2 Axis Lathes, only Multi-Tasking Lathes with Live Tooling.

For a 2 Axis Lathe a wire frame drawing should give you what you want if that is what type of lathe you have.

In general your tolerance problem may be coming from the CAM Software. Sometimes (depending on what software) the translator takes a radius and turns it into spline geometry. In your case a single radius into many smaller radii. Step, and Iges are known for doing this to arcs and radii, where DXF is about the best for wire frame geometry.

If you do not mind my asking, "What CAM Software are you using?" Maybe I can help you a bit more.

 

[dkmc]

I'm using Onecnc.......
ANYthing that will accomplish the task ......I will modify my routine.

 

[Anonymous]

I have no clue about OneCNC, but there is a guy on CNC Zone that does. His handle is HuFlungDung and the link to CNC Zone (hopefully this is allowed) http://www.cnczone.com/forums/

Register like you did for this forum and I'm sure he will be willing to help you. :wink:

That is if it is a OneCNC issue. I could be wrong but I have found that Alibre's Step, and Iges Translators to be very good. I have imported Solid Models into BobCAD/CAM (V21-V22) and a few customers with Mastercam (V8, V9, and X) without any of the problems that you describe.

Sorry I wasn't able to help