Author Topic: Multi pass odd behavior  (Read 6261 times)

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Offline injuhneer

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Multi pass odd behavior
« on: July 15, 2014, 10:04:00 AM »
After a couple of years away (health issues) I am getting back into CNC things.

I updated my Mach install with the recent Mach 3 with wizards. I saw that the old z-inhibit is gone.

So now it is a matter of updating saved code with the Multi Pass Wizard!

I have the latest Mach 3. Running the multi pass wizard against this:

G0 G49 G40 G17 G80 G50 G90
(-- Set Z zero to bottom of part --)
(-- Final Z is set to 1.125" --)
(-- Use Z inhibit to incrementally plane --)
G20 (Inch)
G90
f3
G0 X0
G0 y0
g0 z1.300

g1 z1.125
M3
f6.5
g1 y-9.3 x0.5
g0 z1.300
M5
g0 y0 x0

M30

I put in the values for rapid (rapid height), increment (z increment), and depth (depth limit) then convert.

The path generation dialog comes up and does not dismiss. I have let it run as long at 3 minutes. All it does it keep adding lines to the file:

G0 G49 G40 G17 G80 G50 G90
G20
G90

G0 X0
G0 Y0
G0 Z1.4

G1 Z1.4
M3

G1 X0.5 Y-9.3
G0 Z1.4
M5
G0 X0 Y0


G0 G49 G40 G17 G80 G50 G90
G20
G90

G0 X0
G0 Y0
G0 Z1.4

G1 Z1.4
M3

G1 X0.5 Y-9.3
G0 Z1.4
M5
G0 X0 Y0

G0 G49 G40 G17 G80 G50 G90

G20
G90

G0 X0
G0 Y0
G0 Z1.4

G1 Z1.4
M3

G1 X0.5 Y-9.3
G0 Z1.4
M5
G0 X0 Y0

G0 G49 G40 G17 G80 G50 G90
G20
G90

G0 X0
G0 Y0
G0 Z1.4

G1 Z1.4
M3

G1 X0.5 Y-9.3
G0 Z1.4
M5
G0 X0 Y0 ...

Thousands of times. The longer it runs the longer the file gets. It does not complete. It can be stopped using the Cancel button.

Not only does it loop, the added lines do not actually increment the Z. It stays stuck at 1.4.

Seems simple. Z down, traverse, rapid Z up, return to x0 y0, do it again.

Any thoughts on what would be confusing the wizard?

-Mike O.

Offline injuhneer

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Re: Multi pass odd behavior
« Reply #1 on: July 15, 2014, 04:27:05 PM »
*crickets chirping*

Offline ger21

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Re: Multi pass odd behavior
« Reply #2 on: July 15, 2014, 06:23:50 PM »
Your Z depth should be a negative number. I don't think the wizard knows what it should be doing, as there is no -Z in your g-code.
Gerry

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http://www.thecncwoodworker.com/2010.html

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Offline injuhneer

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Re: Multi pass odd behavior
« Reply #3 on: July 16, 2014, 09:45:40 AM »
Thanks.

As mentioned this is an older file that used the previous z-inhibit function. This being the reason no neg Z was needed (the old z-inhibit understood relative z).

I'll test one file to see if it works with different values. I assumed that since the wizard was replacing the old z-inhibit the function would be compatible but it doesn't seem to understand the relative difference between z1.4 and z1.125.

Since the files will need to be changed in order for the multi pass wizard to understand them it will probably be faster to make new files rather than edit then convert.

-Mike O.
« Last Edit: July 16, 2014, 10:03:18 AM by injuhneer »

Offline injuhneer

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Re: Multi pass odd behavior
« Reply #4 on: July 16, 2014, 10:29:30 AM »
Sorry. Braincloud.

The moves in the old file use absolute rather than relative. I had it backwards.

-Mike O

Offline injuhneer

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Re: Multi pass odd behavior
« Reply #5 on: July 16, 2014, 12:06:50 PM »
G91 was added and the movement made negative (z-0.275). G90 is invoked at the end.

The increments are correct now but the path generation dialog still gets stuck making it necessary to click Cancel.

-Mike O

Offline ger21

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Re: Multi pass odd behavior
« Reply #6 on: July 16, 2014, 12:24:16 PM »
I saw the path generation get stuck as well, but as you say, cancel clears it and the toolpaths appear to be correct.
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html