I just replaced my MPCNC controller (RAMPS) with a Jackpot clone, and it’s working almost perfectly. The new board with the new controllers TMC2209 v3.0 work great. But…
I do sometimes loose some steps in only one stepper. I’m using 1.8A in each stepper but this stepper always loses some steps, an only this stepper as far as I can see. The strange thing is that I can hardly stop or move the same stepper when it’s energized, and can move the carriage with any problem when the steppers are off.
I already checked the set screws in that stepper in particular, since it’s the most probable cause, and it is locked good. Also tried bring the current to 2A without any change.
Can this be a problem with the stepper or should I check anything else before order a new one?
The drivers are cold to the touch. I have a good PC fan over them. The steppers are warm with 1.8, but they get hot with 2.0, so I keep them at 1.8. I already tried at 1.2A so nothing gets hot. Same problem.
And you’re right. The TMC2209 v3.0 is rated for 1.7A continuous operation and 2.7A peak. I think I read the TMC2209 v3.1 specs (2A continuous operation).
I just did a test run with 1.5A and the same file and it didn’t skip.
I can be wrong, but isn’t the max current limited by the drivers and the steppers?
The thing is that so far I was not able to get decent cuts in acrylic because with shallow and slow passes it gets to hot and melts. I’m trying to cut 5mm in 2 or 3 passes as fast as I can so it doesn’t melt, and with lower currents I cannot go as fast.
But it’s probably my lack of experience with this. I talked to a neighbor that cuts acrylic with laser and he is very picky with the acrylic. Some of each melts very easily.
I’m trying with 2mm deep at 800mm/min with a makita clone at fastest speed and I’m getting good results with this settings, but I do loose steps with lower currents (tried with 1.2).
I should probably create a new topic for this to see if anyone has experience with this material and the best settings for it.
That’s true. But at the max spec, they run very hot. The steppers can put enough heat to soften the mounts and then they bend. PLA is very rigid at lower temps, but the rule of thumb is to keep the motors below 60C to protect the plastic.
But it also seems strange that you don’t have enough torque at 1.2A, which is higher than the recommended and we get plenty of torque at 900mA.
If it ain’t broke, then don’t fix it. But I wonder what is out of the ordinary for your build or procedures that is making that happen.
Didn’t thought of the heat softening the PLA. You have a point there, and at 2A it gets HOT. At 1.5 only gets a little warm, like 5 degrees above room temperature, so I dont think this will be a problem.
About the lack of torque, is maybe is the steppers? Maybe the power supply? I’m using a PC power supply with 12V. It’s rated for 20A at 12V, so it should be enough. Can it be the cables to the steppers? They look very thin to me, but so are the ones that came with the steppers. I would bet that I have some not negligible voltage drop across them.
I’m going to try again later. Let’s see if I can finish the project without much troubles.
For what it is worth, I have had to run my steppers at 1.2-1.4A to avoid skipping steps. The steppers never get above 35C. Not sure why. They are the same steppers from Ryan’s amazon link. This is with both SKR and Jackpot using a 12V power supply.
