g-code with master cnc utilities

[SHEDCNC]

I am new to this cnc thing, but have made my own cnc machine out of a HM30 mill/drill, and I thought this would be the hard part, but it was not.
I want to draw a simple design in 2d (rectangular recess's circular recess's etc), then be able to enter the end mill size, choose the milling directions and mill 2.5d ie down a depth stepping as I go.

master cnc utilties works great for semi auto pocketing drilling etc. But when I use a cad/cam program to generate g-code for the master cnc utilities, it interperets the arc's in all sorts of weird and not so wonderful ways.
I put the g-code through cnc simulator and it looks fine. All g-code is in mm with absolute (as this is all master cnc utilities will do) references.

I have tried probably about 30 packages including cambam, deskcnc etc
what am I missing.

Any help is appreciated.

[alexccmeister]

Hi,

I am new to CNC as well so I try my best at this. From what you said with the arc going hair wire. If the simulation works fine and the actual cutting gives yo funny curves, all this sounds like backlash in the leadscrew to me. But I am may be wrong.

I think but please if some expert can confirm this.

[SHEDCNC]

Thanks for the input, but don't really think its backslash in the leadscrew, the errors are instead of doing a small arc it makes an arc 10 times as big?? but it is still an arc.

[alexccmeister]

Could it be your unit is wrong? maybe instead of mm, you are working with inches? Just a thought.

[SHEDCNC]

Thanks but not really, all other g-codes are in mm and actually workfine, even circles work. But it seems to be to do with how it interprets splines from a dxf file.

[joecnc1234]

Try drawing an arc on the spline delete the spline then rerun tool path. If not check cutter comp

[10bulls]

Originally Posted by SHEDCNC ...master cnc utilties works great for semi auto pocketing drilling etc. But when I use a cad/cam program to generate g-code for the master cnc utilities, it interperets the arc's in all sorts of weird and not so wonderful ways.

I don't know if you cracked this one yet, but it sounds an awful lot like arc direction modes. This is the I and J parameters in G02/G03 arcs denoting the center. This can be incremental or absolute and usually depends on an option setting in the processor. It does seem to vary. The gcode needs to match the processor setting.

Good luck!