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makerbase-mks / MKS-SERVO57B

MKS SERVO57B is 3d printer closed loop stepper motor NEMA23 MKS SERVO57 developed by Makerbase that prevents losing steps. CPU is STM32F103CBT6 ARM 32-bit Cortex™-M3 CPU Core,72 MHz. Magnetic encoder is Allegro's A1333LLETR-T Contactless 0° to 360° angle sensor IC ,12bit .This Project open source hardware and code,support platformio build and upload firmware...
https://www.aliexpress.com/item/4000165230349.html?spm=a2g0o.store_home.productList_8356959.pic_8
GNU General Public License v3.0
21 stars 9 forks source link

Servo57B on a Shapeoko boot up issue #3

Open bringho opened 3 years ago

bringho commented 3 years ago

I got interested in using 4 of these on my homebuilt CNC and stumbled on this issue regarding using two motors on the same axis, in my case Y and A axis /reversed). I see no sign of this issue being handled here so here is a shutout about the issue:

https://www.youtube.com/watch?v=GwD5XdX5IYU

mks-viva commented 3 years ago

Hi! Do you want to express that the motor shakes at the moment of power-on?

bringho commented 3 years ago

I guess the Youtube video talks for itself. It's not me who made that video so I have not seen it in real life.

Judging from the video and the setup of the motors = Y axis having two motors GOING IN OPPOSITE DIRECTION my best guess is that you initiate the controller by rotating the stepper motor a number of steps in one direction not taking in account that some CNC mills differ from 3D printers in this respect. Most 3D printers with dual motors for z axis (like the Prusa printers rotate the motor in the same direction to raise or lower the z-axis.

I guess most CNC milling machines is the same if they use ball screws. Then the set up of the Y axis will be looking like the z-axis setup for the Prusa.

Some CMC mills use belts instead and those ysually have the motors for the y-axis going in opposite direction.

My analysis of the video is that the opposed motors are rotating in the same direction be it clockwise or counter clockwise and that builds up tension in the gantry until the less powerful of the motors fail.

The update to counter this problem should either be to introduce a setting to make it possible to reverse the "normal" direction of the motor (which is normally done on the controller board) or to set only the initialisation movement in reverse.

scratchhax commented 3 years ago

Hey gang, I created that video. it looks to be the initialization sequence when you first power them on . I have upgraded to the latest firmware from about 10 months ago as it looks like it was fixed, but they still make a few degree movement at power on.

ghost commented 3 years ago

I have same issue when turn on my 3D printer. Mainboard: GTR v1.0 MKS SERVO57B fw: 1.0.3 (donwloaded from this repo, uploaded with ST-Link)