z axis randomly plunges too deep

Woodworker
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Re: z axis randomly plunges too deep

Post by Woodworker » Sun Apr 27, 2014 9:29 pm

Thanks for that explanation,I would not have immediately come to that conclusion. I am glad that I have the opportunity to see these threads before my machine is fully built.

Is it a "requirement" to have a fan on the driver board for anything beyond writing "Hello World"? I would like to get one ordered if that is the case.
BRuce - SO2 #4798 - IC's Z axis upgrade, customized Z rail and Z motor mount, spindle Dewalt 611

WillAdams
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Re: z axis randomly plunges too deep

Post by WillAdams » Sun Apr 27, 2014 9:42 pm

No, people manage to do milling w/o a fan --- the black stepper drivers / boards are much better about heat than the green ones which were typically used.

It is however, pretty much a requirement if you want the machine to move as fast as it possibly can. Unfortunately, foregoing a fan is one way the kit's price is kept down.
Shapeoko 3XL #0006 w/ Carbide Compact Router w/0.125″ and ¼″ Carbide 3D precision collets
Nomad 883 Pro #596 (bamboo)

Woodworker
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Joined: Tue Mar 11, 2014 1:37 am
Location: 5 miles north of Benson, NC

Re: z axis randomly plunges too deep

Post by Woodworker » Sun Apr 27, 2014 10:07 pm

Understood, I will order one shortly. No reason to stress the driver board and I do plan on upgrades.
BRuce - SO2 #4798 - IC's Z axis upgrade, customized Z rail and Z motor mount, spindle Dewalt 611

SlickShoez
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Re: z axis randomly plunges too deep

Post by SlickShoez » Mon Jun 02, 2014 2:41 am

banana wrote:1-5, not 1-1.5

I've gone over all that could be too loose or too tight. When it plunges too deep it does it smoothly, like it was supposed to and then continues to cut the pattern fine, just on a wrong level. For example when milling a planar level it does the first half fine, then the bit lifts up and goes to do the second half that should be the same level but once it starts it plunges too far down.

On the attached picture it was leveling fine (green highlight) until it was not (red highlight), the green highlighted plain was supposed to be twice as large but I cancelled the milling when I saw it plunge too far down. Bit was 3.2mm ball end, overlap 2mm, the coin is a quarter. Path file in OP.
banana,

Were you ever able to get this figured out? I'm having a similar issue and am curious to know if adjusting current/adding a fan helped.

Thanks!
-steve

Schruminator
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Re: z axis randomly plunges too deep

Post by Schruminator » Mon Jun 02, 2014 1:18 pm

I know during my initial runs I had some erratic behavior that I am pretty sure was missed steps on an axis or two. I aimed two old computer fans I had lying around onto the driver board and I had far, far fewer issues. If you have a fan lying around, find a way to wire it up. It won't hurt anything and it may very well save you a few headaches later on.
1.8m x 1.0m SO2 #3638 / Vectric Aspire / ACME Z-axis / View my photography at http://www.mschrum.com

Llamas
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Re: z axis randomly plunges too deep

Post by Llamas » Tue Jun 24, 2014 7:32 pm

What feed and seek rates are you using? It's been a common thing for the Z axis to miss steps when retracted faster than 250-300 mm/m. On a big retraction at seek (G0) speeds, it can bind up dramatically; but most of the time, the under-retraction is not immediately noticeable. Depending on the controller, different methods can be used to limit the Z-axis movement speed.

Arthur Selin
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Re: z axis randomly plunges too deep

Post by Arthur Selin » Sun Jul 13, 2014 8:23 pm

I have the same problem with the Z axis randomly plunging 2 to 3 times the depth specified in Makercam and especially after the second pass of a pocket operation. A fan cooling the controller does not help. Could the problem be with Makercam or with Universal g-coder sender. Any suggestions..Arthur

WillAdams
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Re: z axis randomly plunges too deep

Post by WillAdams » Sun Jul 13, 2014 8:38 pm

The problem shouldn't be w/ MakerCAM or G-code sender --- just check the G-codes if you're not confident.
Shapeoko 3XL #0006 w/ Carbide Compact Router w/0.125″ and ¼″ Carbide 3D precision collets
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