Need Help!- helical interpolation with cutter compensation

[gwesley]

I am doing thread milling using a two year old Hurco VMX-1 with a dual-screen Ultimax control. If I use cutter compensation (G42), with the expectation of tweaking the final thread depth, the machine moves in an X-Y circle then moves up in Z instead of a combined move in X-Y-Z. If I take out the G42 out of the program, the machine moves as expected and the result is a nice thread. I have contacted Hurco about this and they say I should be able to do helical interpolation with cutter compensation on, but they have been slow to respond with a solution other than asking for the machine's software version. I currently just re-post the thread with a slightly smaller diameter which is time consuming. Any help or suggestions would be appreciated.

[HuFlungDung]

Don't know anything much about Hurcos. Do you also have to command which diameter offset register to use?

Did you provide sufficient (or any) lead in when you turn comp on? Probably the control requires one move 'in the clear' to bring the tool tangent to the profile. Without that initial move, it may think that your threading movement is the initial movement.

[gwesley]

I looked at these again to make sure. I do have a sufficient lead in move. The control uses the offset values for the current tool, which are entered when the tool is defined in the tool table. Thanks for the suggestions.

[jetski]

4 years ago they told us (application engineers working at Hurco) you could not use cutter comp on helix threads). I have cut quadruple lead threads, metric threads, and some bastard threads, on the Hurco, in conversational and have never use comp. It is just as easy to just change the first x distsance in and the Hurco will re-calculate the rest. Just got through a 16 cavity unscrewing injection mold tool last week. I can send you the Hurco file if you want to look at it.

[SKICARB]

Go to the Hurco web sight and they have a help section, or rather a tips section that goes into the detail of helical thread milling. With cutter comp and the ramp in move ramp off ect. Just discovered it this week. Guess they have had lot 's of questions about it. Just did an M45 x 1.5 this week for a one of prototype. The tap would have been 196.00, so thread milling does pay for itself.

[gwesley]

Thanks for the tips and suggestions. I looked at the Hurco site this morning and couldn't find a tips section. The site appears to have been redone. I did find Application Notes and FAQ sections and an article on cutter comp details, but not anything on using cutter comp with helical milling. I would appreciate a link if you have one.

It looks like conversational programming may have to be the way through this for the time being as there hasn't been much help coming from Hurco, or any prospects that there will be in the foreseeable future. Switching back and forth between conversational and G-code will be annoying.

[SKICARB]

www.fishmtc.com/winmaxcnc/ I'm sorry about sending you to the Hurco main page. This is Tom's own web page he works for Brooks out of MA. Does the set up and training for the East coast, North for the most part, I never asked him how far south he gets.