Z Zero lost when switching jobs

I am using a Bitzero and Bitsetter.
Should I be able to switch jobs without re-initializing the machine?

I ran one job (no bit changes) and it worked as expected.
I then loaded a second job using a different size workpiece and used the Bitzero to set x,y & z
When I ran the job it asked for the bit called for in the job, it then read the bit with the BitSetter.
When I started the job it used the Z value from the first job but the X & Y from the second job.

Fortunately I have a pause / resume button and I was able to halt the job. I then hit the e-stop and started over.

The second job worked as expected after a full restart.

Thoughts.

Bill

While zero is persistent the second probing operation should have reset the origin. Could there have been a disconnect in how you specified the origin in the file and how you set it relative to the stock?

Will:

Both files used the lower left corner as the origin for the tool paths.

I used the physical lower left of each workpiece when probing with BitZero.

From your response the probed value of Z should have been updated for the second job. Just as the values of X & Y were.

Bill

Please post a step-by-step set of instructions where you note:

  • what you did
  • what you expected
  • what actually happened

and we’ll do our best to sort this out with you.

Will:

Here are the steps I used. Probably a bit verbose but hopefully without losing clarity.

Bill

Z Height lost when running second job with BitSetter

Machine Shapeoko XL

Carbide Motion 513

The two jobs used the same 1/4” downcut spiral bit so no bit changes were made.

Secure ¼” thick workpiece to spoilboard – using tape and CA glue

Open Carbide Motion

Power on Shapeoko

Connect to cutter

Initialize machine

Router moves to front - center and presents ‘Please insert a tool’

Install 1/4" end mill

Click resume

BitSetter measures bit and returns to front - center

From the Jog menu

Use Bitzero to set X, Y & Z values

Verify X, Y & Z from the Rapid Position menu selections

Load New File

Start Job

Router moves to front - center and asked for bit called from the G-Code file

Install the requested bit

Click resume

BitSetter measures bit and returns to front – center and presents ‘Turn on spindle’

Start router

Click resume

The job runs to completion

Remove workpiece from spoilboard

Secure 3/4” thick workpiece to spoilboard – using tape and CA glue

From the Jog menu

Use Bitzero to set X, Y & Z values

Verify X, Y & Z from the Rapid Position menu selections

Load New File

Start Job

Router moves to front - center and asked for bit called from the G-Code file

Install the requested bit

Click resume

BitSetter measures bit and returns to front – center and presents ‘Turn on spindle’

Start router

Click resume

** The job runs but uses the Z value from the first job as its starting depth **

All steps proceeded normally except for the last. At this point I paused the job, then used my e-stop to stop the entire process.

Hi @72begin,

When you mentioned

what bit is it the two times? Wasn’t it the same 1/4" endmill you initially installed during machine initialization?

I’ll try and replicate those exact steps on my machine when I get some shop time.

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Julien:

The same bit (1/4" downcut spiral) was used throughout the entire sequence.

Thanks for the follow up on this question.

Bill

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So I just printed out your steps, installed a bit in the router (and never touched it afterwards), and then from power off I followed your steps one by one, using a first dummy G-code file after zeroing at 0.25" height, and a second (different) dummy G-code file after re-zeroing at 0.5", and …it all worked as expected (i.e. the second cut properly moved at 0.5" height minus the depth per pass, which I had set to almost 0 to be able to tell easily)

So now the question is, what differs between our setups?

  • I was using CM 521, not 513, I doubt it matters, and I reviewed the change log between 513 and 512 and there is nothing that is even remotely linked to this. Still worth a try (upgrading) ?
  • I did not use a BitZero for zeroing (since…I don’t own a BitZero), I zeroed manually both times. It should not matter if you used the probing sequence normally (correct BitZero model selected, probe on the stock overhanging the corner, probe XYZ, and NO action on the zeroes menu after that)
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Julien:

Thanks for the test. The difference is the use of the Bitzero. For now we will call it a one-off occurrence.

I have posted the project that caused the issue to Cutrocket.com

That was three days ago and it still hasn’t shown up. Not sure what is going on with our friends at Cutrocket as this a second project that is not visible.

When the project shows up on Cutrocket maybe someone will be able to further test.

Thanks, Bill

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