July 3, 2019 at 1:32 am #105050
I noticed that one of my motors on the X axis is much weaker than the other three. What could be causing this problem? It moves but it’s far less powerful than it should, this also makes it quite easy to be rotatated when it should be holding the position.July 3, 2019 at 9:47 am #105068
How is it wired, what drivers, what board, what firmware, what stepper? The question is just to general to help.July 3, 2019 at 10:03 am #105074
I’m using the lcd dual endstop firmware, and the hardware suggested for the arduino/ramps build, I’m using cheaper clones for the arduino and the ramps, and the same drivers shown in your build instruction, plus generic chinese nema 17 motors off banggood.
I wired it to its own driver as I’m using the dual endstop firmware.July 3, 2019 at 10:41 am #105079
Check the stepper voltages. One could be lower than the other.July 3, 2019 at 11:03 am #105085
Erwin VigiliaParticipantJuly 16, 2019 at 9:19 am #106282
I have encountered the same problem with my Lowrider Z axis and adjusted my Acceleration distance and Start feedrate in Estlcam to compensate. On my new Lowrider I am using an Arduino Uno, CNC Shield, with the 8825 drivers – reference voltage adjusted to 0.8V for my Nema 17 motors 1.7A 84 oz.in. One Z motor started acting up when the Estlcam settings were set to default (long story, two computers) with Acceleration and Start feedrate at 2 and 2 and Max accel to 50mm/sec. Changing them to 2 and 8 and slowing the Max feedrate to 40 seemed to solve the problem. I had also noticed that moving the Z steppers very slowly prevented the ‘weak’ Z motor from acting up.
I have the two steppers on the Z axis wired in series as recommended but the consequence of that as I understand it is a voltage reduction:
“The same current flows through each part of a series circuit. The total resistance of a series circuit is equal to the sum of individual resistances. Voltage applied to a series circuit is equal to the sum of the individual voltage drops.”
In other words the amps stay the same in a series wiring but the voltage is divided between the motors. I will also be trying a 24 volt power supply and see what results I get with that. It should solve the problem.
My final step will be to wire the steppers individually to TB6600 drivers (which I was going to do anyways, long story, 4 axes, Arduino Mega) and each motor will get a full 12 volts.
Being no expert, I may be off base with my electrical theory and if so hopefully someone will correct me.July 16, 2019 at 3:47 pm #106319
The OP hasn’t chimed in for bit, so maybe he solved his problem…
Being no expert, I may be off base with my electrical theory and if so hopefully someone will correct me.
Nothing wrong with your theory (Kirchoff and Thevenin would be proud). What matters here, in terms of voltage, is your motor coil rating and your stepper driver specified min Vcc. For the TB6600 and 8825, that is 8.0V and 8.2V respectively. I don’t know which motor you’re using, but the OP’s motors are rated for 2.8V (at 2A) per phase. 8825’s which are rated for 2.5A max, really less, the way these particular modules are built… barely adequate heat sinking. Forced air helps. The TB6600 is rated for 4.5A peak. Bottom line, 24V should work for his application.
- This reply was modified 5 days, 8 hours ago by Erwin Vigilia.
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