Z Height Limit

[GarySeibs]

Not sure if this is hardware or software and if anyone has any insight I would appreciate it.

I've got a Techno-Isel 4896 in my high school shop that I've been using since 2005. I know that it's getting a bit long in the tooth but the machine is still great (that and I don't have $30K+ to replace it). It's a stand alone station in my school shop and is run by a PC that I only use to run the machine; all design and toolpaths are done on other computers and we migrate toolpaths to the machine with thumb drives. In short, I got my school to be a pretty early adopter and I've been using this one since it was new so the process is good and works for us.

In September my PC gave it up and I was able to re-purpose another one to run the TI Router (which I've done before) but since then it's been raising to the Z limit and stopping when it finished the part. On my machine this stops everything and you have several clicks to restore controls. It's been driving me up a wall and I can't find the setting to correct it.

My software is set up as usual: we use inches, Rapid Z Gaps set at .2, home position gap set to a Z of .5. I've been using these settings for a number of years without an issue. I've poured through the interface settings as well and I'm stumped.

Any help or insight would be greatly appreciated.

Gary

[SteveNelson46]

If I understand the problem correctly, I would start with the post processor. Check to see what commands are used at the end of the toolpath.

[adze_cnc]

It sounds like at some point the post processor was modified to prevent something like that and now with the new install on the new computer it is back.

If you're OK with modifying your post processor the change is easy. The following is an excerpt from the Techno Isel inch post processor from VCarve 9.519 but v10.x and v11.x will be similar:

Code: Select all

begin FOOTER

"G0[ZH]"
"M5"

The offending line is the one that does a G0 to the z-home (ZH). Remove that and it won't go to the z-home at the end of the job.

But. Before you modify the post processor you might check your job's materials settings (on the toolpath tab):
 

 
to see that your Z gap above material is set to a reasonable value.

[GarySeibs]

Thank you for the direction. When I get a chance I'll dig into that. I'm no programmer but I'll see what I can do.

Yep, that's where I looked first. My settings are similar with Rapid Z Gaps set at .25 and Home / Start position Z at .5 inches.

[GarySeibs]

So here is the last few lines of GCode on a part we ran (X4) this morning and each of them hit the Z height limit when the part was finished. I'm not a coding wizard but it appears on this one it's supposed to be going to a Z of 0.6 and yet it hit the max limit and was still rising around 5".

I'm not sure how to edit the post processor.

G1Y0.7500
G1X2.5000
G1X3.5000
G1X4.5000
G1X5.5000
G0Z0.6000
G0Z0.6000
M5

So this is what I discovered looking at my PP:

+---------------------------------------------------
+ Commands output at the end of the file
+---------------------------------------------------

begin FOOTER

"G0[ZH]"
"M5"


My problem is I have no idea how to access and edit that "G0[ZH]"

[SteveNelson46]

Just a regular text editor like Notepad should work. Scroll to the bottom and you should see the offending line.

[FixitMike]

After modifying the post processor, be sure save it with a new name so you don't mix it up with the original.

[GarySeibs]

Just a regular text editor like Notepad should work. Scroll to the bottom and you should see the offending line.

Thanks and I get that part but here is where my lack of expertise is evident. I don't know where to go to open the PP. I can view it in the "Save Toolpath" section but cannot edit. Where do I find the editable file?

[SteveNelson46]

I'm using Aspire and my post processors are in:

C:\ProgramData\Vectric\Aspire\V11.5\PostP

The best way is to open VCarve, go the the file menu and select " Open Application Data Folder".

[FabLab Wageningen]

Your GCode looks, er, weird:

G1Y0.7500 = straight cut-mode move to Y-coordinate (X and Z remain the same)
G1X2.5000 = straight cut-mode move to X-coordinate (Y and Z remain the same)
G1X3.5000 = straight cut-mode move to X-coordinate (Y and Z remain the same)
G1X4.5000 = straight cut-mode move to X-coordinate (Y and Z remain the same)
G1X5.5000 = straight cut-mode move to X-coordinate (Y and Z remain the same)
*** okay: why are there 4 moves when 2 would be sufficient ?
G0Z0.6000 = straight non-cut move to Z-coordinate (X and Y remain the same)
G0Z0.6000 = straight non-cut move to Z-coordinate (X and Y remain the same)
*** the second command makes no sense
M5 = spindle off

what do I miss ?

Second: if you aim at a Z height of 0.6" and you hit 5" check both your save Z-height and whether you mix mm and inches, please.

Marcel

[GarySeibs]

Update....

Thanks for all the suggestions and guidance on this one. The problem is solved and it's no longer rising beyond the limits and forcing a stop. I'm running parts again with no issues and no stoppages.

My solution: I didn't do anything, I didn't edit any post-processors, etc. I made no changes to any settings what-so-ever and now it's running just like the old reliable that it's been. I have no idea.