Help Z keeps crashing into plate in Mach3

[Txchevy]

This is More of a software Issue but, it is plasma related. Either way I'm in need of some help PLZ!

Basic setup:
5x10 precision plasma gantry
Upgraded 2 start 10 tpi floating Z
CandCNC Bladerunner AIO 620 in oz steppers
Mp3000 DTHC
CAD _ Solidworks 2010
CAM_Sheet Cam TNG
Post Processor_ Mp1000 -thc
Controller_Mach3

I'm having some trouble figuring out why The z is not staying in the same plan for each layer sent from sheetcam TNG to Mach3. The simulation in sheetcam runs the part perfectly but in Mach it steps each layer down below the actual surface of the plate causing the head to crash and trying to reach a negative number. I have brand new consumables but need to figure out this issue before I go any further.

The test part is roughly 5" x 3" with (4) 1/2" holes and one 1.75" hole in the middle. The outer cut, center hole and 4 smaller holes each have their own layer respectively.

Sheet cam Simulation- which runs perfectly


Mach 3 toolpath - Its a bit hard to see but the pink lines are holes. The step of each layer is easily seen.

[rock4xfab]

Did you set your Torch offset in Sheetcam post... Not that farmiliar with sheetcam just yet so I dont know much about the layer thing. My work around was to seperate posts.. heheh

[Txchevy]

No i didn't. Mind explain what that is, or where it is? The layer thing is simple really. Create separate tools for each feedrate and offset you need. Then select your operation, layer and offset to as well as the lead in and lead out.

To set layers select the contour tool ( arrow with a C at the top of the tool bar) then right click and select new layer then simply name each new layer.

I went through each tutorial several times it helped alot even though they weren't plasma based.

Btw I read you mentioned something about z offset over on plasma spider. Where do I enter all these new variables? Damn seems like I get one thing working and then 100 new issues pop up. lol

[plain ol Bill]

Give this a try. Put a piece of plate on the table. Jog over until your torch is above it. Reference the Z axis - the torch will go down until it contacts the plate and then will rise just a fraction until it clears the switch. Your Z DRO should be at 0.0000 now. Jog your torch up until you can JUST slide a piece of paper between the torch and the metal. Look at your DRO - that is your torch offset value. Do this several times and average the results.
Your torch offset value is entered in the Sheetcam post you are using (I use MP 1000 THC).
Hope I haven't confused you and this helps.