Trying to mill a circle, not going to plan, and other issues.

[Crazy L]

Hi guys

I've not posted here a lot as I've only just started to learn a machine I bought back in June. Alas. at work I'm a heidenhan guy, but have worked with fanuc up until a decade ago. My machine uses Mach 3 and last night was the 1st time I cut metal. When I shut the program down, it asked me to save fixture data, which I assumed was the datums I had set on my job. Upon firing up today, it had lost position, so I had to reset them, any ideas why?

Next, I'm doing a bore with a 6mm cutter, the data is in the tool page. I go down, comp on in Y, circular interpolate, spring cut, then comp off. It's a 19mm bore.

This is my program:

G91
G1 G41 D1 Y9.5 F100
G3 J-9.5
G3 J-9.5 (spring cut)
G1 G40 X0. Y-9.5 F500
G90
G0 Z2.

However, when comping on it moves in X, and the final Y pos in Y once comped on is 8.49something, wtf, when it should be 6.5. Then, despite my datums being set correctly, the circle is off centre (my datums are in the circle centre).

Would anyone have an idea what I've not set correctly, or what I've forgotten/not done? I'm new to this home machine lark so any help would be greatly apprec'd.

Ta

[magicniner]

When I shut the program down, it asked me to save fixture data, which I assumed was the datums I had set on my job. Upon firing up today, it had lost position, so I had to reset them, any ideas why?

It doesn't work in all versions, I always park it in a known place.

Can't help with the code, I apply my cutter comp in CAM and it works OK.

- Nick

[Crazy L]

It doesn't work in all versions, I always park it in a known place.

Ah, like a park position on an old Interact, good idea, I didn't think of that. Learning curve and all that.
OK, I didn't know that either, perhaps y version is an old one or something. Thank you very much.

Got round the circular pocket issue for now. I found if I used centre line of cutter rather than comping on, it works.

[Clive S]

I've not posted here a lot as I've only just started to learn a machine I bought back in June. Alas. at work I'm a heidenhan guy, but have worked with fanuc up until a decade ago. My machine uses Mach 3 and last night was the 1st time I cut metal. When I shut the program down, it asked me to save fixture data, which I assumed was the datums I had set on my job. Upon firing up today, it had lost position, so I had to reset them, any ideas why?

Did you re home the machine on switch on first.

[Crazy L]

Did you re home the re machine on switch on first.

Hi Clive

Y'know, I don't actually remember for sure. Although thinking about it now, I think I did reference it, yes. then watched in dismay as the readout changed, lol.

[EddyCurrent]

Have a look at this Screenset; http://www.thecncwoodworker.com/2010.html
I find it makes setting zero and using fixtures so much easier.

[Crazy L]

Ta EddyCurrent

I'll have to find out what version I'm running as I have no idea.

[Ger21]

To use comp in a circle like that, you need a lead in and lead out move. And different versions of Mach3 may require different lead in moves, as the comp was changed at one point.