Rogue Cutting When using PhotoVcarve in VCarve Desktop 10

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custer
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Joined: Wed May 01, 2019 7:10 pm
Model of CNC Machine: Chinese 20/30 Now 30/40

Rogue Cutting When using PhotoVcarve in VCarve Desktop 10

Post by custer »

Hi, I wonder if anyone has had the problem that I have at the moment.
I was using VCarve Desktop 10 to photo carve a picture, all the settings are the same as I have used in the past on other projects with reasonable results.
Line Spacing 5
Depth of cut 1.016 mm
Vbit 60 degree

The cutting begins at the correct depth and then after the first cut the next cuts very gradually become deeper until approximately 7mm and levels out until the end of the project.

Has anyone come across this or anything like it.
Thanks in anticipation.

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Adrian
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Re: Rogue Cutting When using PhotoVcarve in VCarve Desktop 10

Post by Adrian »

Sounds like a problem with the machine itself or a procedural error with setup on it. Have you got the right bit in and did you z-zero to the correct location?

Presumably the preview is showing no cuts deeper than 1.016mm and the max cut depth when you hover on the toolpath is showing the same?

custer
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Joined: Wed May 01, 2019 7:10 pm
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Re: Rogue Cutting When using PhotoVcarve in VCarve Desktop 10

Post by custer »

That's right Adrian no problems shown up in preview, yes correct bit chosen and Z-Zero checked.
All I can think at the moment is that the G-code has somehow become corrupt.
What I don't understand is, on similar setups there are no problems, which on the face of it rules out a machine malfunction (although I am still investigating why Mach3 is not showing any discrepancy in depth. It does not show any cutting depth deeper than the 1.016mm
when clearly it is cutting much deeper.

Thank you for your helpful reply.

I

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TReischl
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Re: Rogue Cutting When using PhotoVcarve in VCarve Desktop 10

Post by TReischl »

Mach3 will typically not load a "corrupt" gcode file. It will post all sorts of errors.

If Mach3 is telling you it is at the correct depth then you are definitely having a lost step issue of some kind. Mach has no idea if the steppers are going where they are commanded, there is usually no feedback. So by Mach displaying the correct numbers that tells you the gcode is not corrupt.

A big hint, about 99% of the posts with this type of issue turn out to be either mechanical or electrical issues with the machine. The list is long and distinguished of what can all go wrong on the machine. Static electricity, loose set screw, slipping belts, bumping into a hard stop, ad nauseam. Don't feel bad, if a person has not had one of these issues then they probably have not been running their machine very long.
"If you see a good fight, get in it." Dr. Vernon Jones

custer
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Joined: Wed May 01, 2019 7:10 pm
Model of CNC Machine: Chinese 20/30 Now 30/40

Re: Rogue Cutting When using PhotoVcarve in VCarve Desktop 10

Post by custer »

Thank you very much TReischl for your clear concise answer, my investigation is going to be along the step loss route.
I know this is going to be a quite a challenge but hey ho knowledge is the key to future trouble shooting.

Best regards,

custer

wstrong
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Re: Rogue Cutting When using PhotoVcarve in VCarve Desktop 10

Post by wstrong »

I have had my Z axis change during the cut twice.
first time the couple-er between the stepper motor shaft and the screw shaft was loose.
tighten it and everything was fine for years until I took out my spindle motor and changed it.
didn't get the replacement tight enough and when I cut, the Z axis moved again.
tightened up the spindle mount and everything is right in my Little Vcarveing world again. :D

custer
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Re: Rogue Cutting When using PhotoVcarve in VCarve Desktop 10

Post by custer »

Thank you all for your replies, during my investigation into the problem I accidentally knocked the stepper motor connector to the Z axis motor and GUESS WHAT!!! the Z Axis momentarily paused plunging, but Mach 3 still recorded it as continuing to move. On closer inspection two of the pins (1 x green & 1 x black) were able to retract slightly and then come together each time the machine stopped to re position for the next pass, sometimes causing a power disconnect (as far as I can understand it). I have replaced the connectors with new one's and all appears fine.

Many thanks,
custer

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TReischl
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Re: Rogue Cutting When using PhotoVcarve in VCarve Desktop 10

Post by TReischl »

That's a new one! Thanks for getting back with this.

Steppers can be closed loop if an encoder is attached, but that is pretty rare.

Just think of mach3 like a garden hose being held by a blind man. He has no idea if he is watering the petunias or his dog.
"If you see a good fight, get in it." Dr. Vernon Jones

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