[decoder]

Hi, i am a new cnc user.I have bought an axminster x1 mill and i have converted it to cnc using stepper motors. My problem is, tool offsets, how do you achieve tool offsets?
Supposing i want to cut a square hole and i set the tool offset i would expect the tool to follow the path of the square but one tool radius away from the original cutting line but in fact what is happening is the tool offset is just creating a new zero starting point. What am i doing wrong.
I am creating my parts in acad14, saving them as dxf files and then converting them to g-code for my macine.
Can anyone help please.
Clive (UK 50 miles from London)

[Bubba]

You say you are using a dxf file to convert your tool path to g-code.

WHAT program are you using?
I am going to take a guess that you are using ACE? If this is so, you have to do the path offset in CAD (preferably on a separate layer) and then tell ACE to follow that path. The offset will be the radius of the tool that you plan to use.

If you are using a program like sheetcam (also a UK product), then you do not do the offsets in cad, you tell sheetcam the diameter of the cutter and it will do the necessary offset.

To properly answer your question, obviously more information is needed!

[ger21]

It sounds like you're expecting TurboCNC to compensate based on the tool size in the tool table. Is that correct? Because that's not how it works. Cutter radius compensation is normally used by calling G41 or G42. Unfortunately, TurboCNC doesn't support cutter comp.

[The Blight]

ger21 is right. When writing up a program, you have to take ther redius of the tool into consideration because TCNC doesnt do that. The tool offsets are mostly for the length of the tool.

[decoder]

Yes i am using ACE, i didnt realise the program had to compensate for the offset, i must have thought it was a magic compensating computer program.
Just suppose i wanted to cut out the shape of say a sheep, how do i compensate for tool offset?,do i just scale the whole thing or modify the g-code values individually?
Also,when i cut say a square hole, the cutter doesnt go round the hole sequentially, it jumps about, can this be prevented easily?
However, has anyone else converted an axminster x1 mill? If so, how did they drive the Z axis?, move the whole column or just lower the head?.I dont think my steppers are man enough to move the column.Thanks for all your help
Clive

[ger21]

Do what Bubba said, and offset the path in your CAD program by the tools radius.

As for the jumping around, you can try the optimize option in ACE, but it may not always work. It's $150, but SheetCAM will give you much more control over the g-code creation, and it can do the offsets as well.