Newbie- DaVinci mill starts below the work piece.

[benjaminhtg]

I'm running a Techno-Isel DaVinci Stepper Mill using MasterCAM X MR2 and the "Techno Stepper G-Code Interface" provided with the machine. This is a 3-axis mill.
Everything seems to be working correctly with the mill and the control software.
The problem seems to be with MasterCAM. I don't know why, but it always starts with the z-axis below the workpiece. If I bore the mill manually into the workpiece so that that tool is at the bottom of the work piece everything works great. The mill goes up and runs through all of the tool paths, then returns to the bottom of the workpiece.

The start of the G-Code looks like this, The second line down seems to be the problem. When it gets the machine goes up 1.105 inches. it later returns to the starting position below the workpiece.

%
G0 Z1.105
G20
G0 G17 G40 G49 G80 G90
T304 M6
G0 G90 X1.3868 Y2.138 S2139 M3
Z1.1
G1 Z1. F8.56
X1.4233 Y2.1745 Z.9635
X1.4598 Y2.138 Z1.
X1.4233 Y2.1745 Z.9635
Y2.9949
Y3.0113 Z.961
Y3.0304 Z.9523
X1.429 Y3.0339 Z.9558
X1.4511 Y3.043 Z.965
X1.4709 Y3.0478 Z.9697
X1.4851 Y3.0489 Z.9708


What settings do I change to fix this?

[John_B]

I don't think it's the G20 in the second line causing your issue, that is normally the code for inch programming.

What I think is causing your problem is the first line, where you have the "G0Z1.105" command. This is moving the spindle down while the control has not accounted for your Tool Length Offset yet. This line I would suggest moving much lower...

Then later you call up the "T304M6" line which should initiate a toolchange. You should have the Tool Length Offset call after the toolchange, some controls don't need a seperate code to initiate the TLO though... I couldn't find anything on that control to see what it requires.

I would suggest something like this:

G20
G0 G17 G40 G49 G80 G90
T304 M6
G0 G90 X1.3868 Y2.138 S2139 M3
(Tool call code if there is one, like G43 for Fanuc) Z1.1
G1 Z1. F8.56
X1.4233 Y2.1745 Z.9635......


Rgds,
John

[emonje]

"G0Z1.105" seems to be the problem to me as well, it shouldn't be there before tool length has been taken into account.

Do you have experience editing post processors? May be you can fix your post processor so that no z movement is made before tool offset is called.