[Lathe] Helping A Newcnc'r: Tools All Off On Turn Runs

[countryguy]

Hi everyone. I have dolphin cam and try to help out users on the forums for both dolphin and shopmaster. I am not yet a turn CNC guy. A post at the other places by him have gone unanswered so I wanted to give a try here for him.
The original post is below. We have spoken a few times so I will try to add a preface here as well.
My understanding was that the part in dolphin is completed with 2 tools. 1 a peck and 2 a turn run with some convex shape to a rounded piece of stock.
Mach3 seems to show it correctly
A run will start. Mach3 shows the tool hitting the piece
But the turn tool will be 1" away yet.
The peck run will be no where near depth.
Dolphin has checked all his offsets and setups. They are fine ( but not validated)
Shopmaster took a look. Noted it should all work. Nothing fancy.

I asked about a test run. Forget the production part. Make a 1" piece turn down .005 Keep it horribly simple. Post the gcode up here and maybe we could help? Or anything you gurus suggest. He's a really nice guy and sometimes you just need to ask in the right place. And that is here on HM

Here is the original post
So I am am new to the cnc world and I am so confused... I have had a post processor made to my parts from Micheal with dolphin... I upload it in mach 3 on my machine and it seems that I can not get things to line up... I have set all my tool offsets on mach 3 and a cording to dolphin everything is at 0 also.. but when I run a part everything is off... tool 1is in the right place but my part isn't close to the correct measurement... tool 2 is a peak drill and it works but 0 is 2"off.. and them tool 3isn't even close... I hope this isn't 2 confusing but something isn't right... can someone help

 

[JimDawson]

Either the machine (encoder/stepper) calibration is way off, or the machine zero is not in the right place. Not being a CNC lathe guy either, I might be tempted to set zero on the spindle centerline and work everything from there. Not sure if this is the correct way to do it, but that would put all of the part dimensions in the positive quadrant.

Anybody feel free to jump in here, you proabaly know more about it than I do.

 

[chevydyl]

when I ran my mill as a lathe using mach3, FIRST! make sure that the gcode you made is DIAMETER measurements, then check to see that mach is in DIAMETER mode, the x zero is spindle center, Z zero is the face of the part, all your cuts are in Z negative
So, face the part using mach, zero Z axis
now jog the X into the stock od and turn it down, don't retract in X, stop the machine and mic that, then enter that number into X DRO, now you should be able to jog the tool Z positive X positive and then run the part, with your hand on the estop

you have to make sure that your steps per inch setup is correct in motor tuning, you can verify with an indicator

 

[Wreck™Wreck]

Here is the original post
So I am am new to the cnc world and I am so confused... I have had a post processor made to my parts from Micheal with dolphin... I upload it in mach 3 on my machine and it seems that I can not get things to line up... I have set all my tool offsets on mach 3 and a cording to dolphin everything is at 0 also.. but when I run a part everything is off... tool 1is in the right place but my part isn't close to the correct measurement... tool 2 is a peak drill and it works but 0 is 2"off.. and them tool 3isn't even close... I hope this isn't 2 confusing but something isn't right... can someone help

If all of your tools are offset from tool #1 make sure that this tool has offset values of X .000 x Z .000
I do not know anything about your control in particular but lathes that I have used will offset tool #1 by the offset values entered, for instance you may face and turn a test sample to 1.000 in X and .000 in Z and it will measure, when a program is then run it will add any offset added to tool #1.

Every other tool will have this offset plus it's own offset relative to tool #1, set it with 0 offset and use the Work Shift.

Worth a try, Good Luck

 

[Wreck™Wreck]

If all of your tools are offset from tool #1 make sure that this tool has offset values of X .000 x Z .000
I do not know anything about your control in particular but lathes that I have used will offset tool #1 by the offset values entered, for instance you may face and turn a test sample to 1.000 in X and .000 in Z and it will measure, when a program is then run it will add any offset added to tool #1.

Every other tool will have this offset plus it's own offset relative to tool #1, set it with 0 offset and use the Work Shift.

Worth a try, Good Luck

Edit: On lathes that I have used the offsets are relative not absolute therefore if the tool will turn a 1" diameter in absolute it will be offset to it's offset value from there when programmed.