Segmented linear moves for arcs?

[Dylwad]

With my cad/cam software, ellipses show up as polylines, and the lengths of the facets is set in cad.

[Spencer myers]

Aussie cnc, Ya it kind of is a bad picture I have one that I did in mdf and you can the ridges more clearly. The plastic did tend to fray, I don't think it was tearing though this was done with a straight bit and went around about 50 times moving down every pass to create the 1/8 in. round over. Idid slow the feed rate down real slow and there was no difference at all. I have not actually cut out another part with the facet tolorance at .001 it was at .1. Just moving and hearing the machine sounds like it will come out smoother. When get some time on saturday I'll cut out a piece. And post it for ya.


Dylwad, do work with solidworks and solidcam also? What do you mean when you say ellipses show up as polylines, can you explain in a little more detail please. When you say the facets are set in cad, is it different or do you get different results setting it in the cad verses the cam. I'll have to look into that if it is in fact different.

[Sheepspeed]

I think I've also got the same problem. I'm also using Mach3, but I think it's a post pro issue, I'm using the FAUNC post. Did you ever get to the bottom of this??

[simila95]

So has anyone figured this out? seems to just be solidcam as i never had a issue with mastercam. you can see in the pic where it happened. only happened on the top and bottom arcs of the circle not the sides. Im running the tormach post. Its SX3 benchtop mill with mach3.
bracket

[johncito]

Hi everyone, i have some problems with faceting in the diagonal sides and in the curves, as you can see in the photo, mygcodes doesn't come out with G2 and G3, I can't understand if that depends of my sketch, my postprocessor, etc.

I'm working in a self made cnc mill gantry with three axis with servo motors and I'm using Mach3 as controller and solid works as cad and solid cam. I have to say that some times the pieces' comes out not so bad, but some times even when I adjust in the “point interpolation” and check “approximate arcs by lines with tolerance 0.001mm” the arcs comes out with so many faces and the diagonals comes out ugly... I tried to work with 2d machining and with imachining process but the result was the same. I'm working with a post processor called mill 3xb I tried the fanuc but the gcodes doesn't comes out with the G2 and G3, comes out with so many points in Y and X plane.
I really appreciate if someone can help me...

[johncito]

This is the gcode that comes out from my cam to do the photo part

[sae_fernando]

Hi Johncito, I've solved the same problem after read this discussion -> Solidcam - Gcode not creating smooth radius

Additionally you can watch to this movie ->

Hope it can help you.

Good luck . Fernando Borges from Brazil