Motor Currents
-
A risk of going too low is that if you get a blob or curl up on your print and the head hits it, at lower currents the motor is more likely to skip steps. Also at very low currents, the microsteps are less uniform because the detent torque becomes significant in comparison to the torque due to current. That's why I suggested a minimum of 50% of rated current.
The motors on my delta are rated at 1.68A and I run them at 1.0A which is about 60%. The heat generation increases with the square of the current, so at 1A they only generate 35% as much heat as they would at full current.
-
I might build a separate machine running another duet simply for speed to save me keep switch up settings and config.
Thank you!
That sounds a bit extreme. Don't forget that just about anything that goes in you config.g can be overridden. So, for example if you wanted to increase the motor currents in order to be able to print a particular item faster, you can change them in the start g-code of you slicer (and put them back to "normal" in the end g-code). I do a similar thing with my homing files but in this case I lower them at the start in order to limit potential damage in the (unlikely) event of an end stop not triggering, then put them back up at the end of the homing file. Be aware also that you can use the "I" parameter in your M906 command to set the motor idle factor. I run my 2.0 Amp steppers at 1.8 amps for printing (because I have a big heavy hot end to throw around) but lower this to 20% when the motors are idle which is more than sufficient for my machine.
HTH
-
Better may be to have a pair of macros a high speed one and a low speed one rather than mess with the Slicer settings each time mind having said that you'd need to anyway to tell the slicer to speed up.
Beauty of S3D is that you can set up different profiles/processes for just this?
Doug
-
Hi Doug,
You could do it all with a macro - just add an M220 command to increase the overall speed. That's a bit crude though as you'd probably want to keep things like bridge speed, small perimeters and gap fill quite low. In this respect, Slic3R will do the same as S3D. You'd just put the motor currents in the Start and End gcode section of your printer then click Save As and call it "MyPrinterHighCurrent" or some such. Then in "Print settings" change the speeds but selectively rather than globally the do a save as "Fast" or some such. So, you can easily toggle between standard and high current printer versions and also standard and fast speed.
Ian
-
There is always more than one way to skin a cat as they say lol
-
There is always more than one way to skin a cat as they say lol
Totally agree, and the best way to skin a cat varies from individual to individual depending on what tools they have available and how familiar they are with those tools.
-
Exactly?
-
Hi everyone,
In the recommendations they say we should use motors with rated current of at least 1.2A. Why ? What if I use a motor with lower rated current ?
And what change when I run the motor with lower or higher current ?
Thanks -
If you use a motor with a lower rated current, then unless it is a very short motor it will have high inductance, and that will limit the maximum available movement speed.
-
What about stallguard on the duet wifi? If M906 sets the maximum allowed current, then what determines the normal operating current?
-
M906 does set the normal operating current.
