Homing Error

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Wcantrell2020
Posts: 4
Joined: Sat Feb 06, 2021 3:39 am

Homing Error

Post by Wcantrell2020 » Sat Feb 06, 2021 3:57 pm

Once I set home zero, it doesn’t go back to zero when I run the homing cycle. If I set z=0, and I travel up 20mm, and then click home, it travels back down FURTHER say 25-30mm, putting the bit into the surface. I have calibrated my XYZ, so if I tell the machine to move any direction 20mm, it travels that distance. I don’t know what settings I need to adjust to fix. I’m running nema 23 (425oz) mottoes with dm542t drivers and 36v power.
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Bertus Kruger
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Re: Homing Error

Post by Bertus Kruger » Mon Feb 08, 2021 6:35 pm

Could it be that your homing direction is in the wrong direction?

Wcantrell2020
Posts: 4
Joined: Sat Feb 06, 2021 3:39 am

Re: Homing Error

Post by Wcantrell2020 » Wed Feb 10, 2021 6:48 pm

No it’s something else. I first tried calibration using a ruler to measure the distance. Then, I made a 150mmx150mmx14mm square test piece to measure. Once I finished, I did a test run on a part for a dust shoe (see other pic). For the dust shoe I am using 2 bits. I do the first 1/8” bit, the machine goes back to home. It cuts accurately. Then I go to the 1/4” bit, and it does its cuts accurately as well. But they don’t align, like the zero shifted.
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humner
Posts: 3
Joined: Thu Jan 14, 2021 9:37 pm

Re: Homing Error

Post by humner » Fri Feb 12, 2021 10:46 pm

There are 2 issues, your homing error/issue and the zero shifting - I don't believe they are related.

I can't comment on the homing issue yet. Can you share your entire GRBL config? The ZERO issue could simply relate to how you have set $1 which is the Step idle delay setting.

If you don't set it to 255 then you could easily move your gantry while performing a tool change which will shift your zero. Read up on this setting.

Be mindful on setting $1 to 255 though - if you do set it, check your stepper driver for a half current mode - you may want this enabled so that your steppers are not at full current during idle but will still give you plenty of holding torque for changing a tool.

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