Have a 3018 board with current A4988 stepper drivers, bit noisy and not great at speed.
I have been playing with speed on 5.5watt output diode laser, and to speed up image scanning I have been pushing the limits of motor speed, for white space scanning.
So far on A4988 drivers 12,000mm/min on 12v supply no steps missing, problem was the noise, so i bought a couple of TM2208 drivers and WOW nice silent as a whisper , Vref set correctly at 90%.
Great, until after a few jobs 4 hours later turned off the laser and , went to start up, both drivers fried.
Ow well the steppers are Nema17 with a draw of 1.5A so was pushing the quiet 2208’s se la vi.
slapped in the old A4988’a and off it went , so played with the max speeds and with an uprated voltage of 19v on the board to replace the 12v the max speed on gt2 gear was achieving 19,000mm/min with 1500mm/min acceleration, and not thumping or missed steps on white space set at 16000 mm/min the problem is the noise.
So my next planned move is some external drivers like the TB6600’s, I will leave the Z axis on the control board as its just there for material height focus being set at 0.0 so no messing with the lens after set.
Could any one shed some light, excuse the expression of the TB6600 is it over kill or would i be good using some DRV8825’ as they handle a higher current than the TMC drivers, and help or previous experience with either the sound levels on the TB6600 or the DRV8825’ would be grateful. from playing I have realised that it the Voltage that gives the speed and the current that holds the torque.
It’s the white space speed I am after as on big print A3 images it can save bundles of time. or on a full bed of multiple coasters etc.
I’ve played around with various stepper drivers, though don’t consider myself an expert.
4988’s are solid and cheap but, as you say, quite noisy.
I’ve used the TMC2130’s but not the 2208’s you mention - yes, very quiet but not so much torque (due to how it processes the microstepping) and some of the clones are hardwired into one operating mode (that should be user settable)
Myself I would have gone lower than 90% for Vref - perhaps 70% - the current (1.5A) quoted for the stepper motor would be an absolute max and may not be fully accurate.
Also, bear in mind (maybe you know) that the TMC2100’s (maybe 2208’s also) don’t use Imax (max current) as the value in setting Vref (like many other drivers) but use the Irms (average of the current -ie about 70% of Imax)
You only need enough torque to move the laser head without skipping steps/ stalling and a higher Vref won’t give greater speed. (Saying that - I presume you’re 3018 is used as a mill also, so maybe you do need more torque)
Do you have fan cooling on your controller?
I was wondering if your steppers cooked in their own heat after the power off. I’ve added copper strip extensions to some of my driver heatsinks.
DRV8825’s worth a go, cheap enough to try out, a lot quieter than the 4988’s with 1/32 stepping. I don’t think they offer more current output than the TMC but more than enough for a 1.5A NEMA 17.
I don’t know much about the TB6600 & external drivers.
Seems to be max 1/32 stepping same as the 8825, I would guess they play a similar tune to them.
Unless you were going for bigger motors, I can’t see a great advantage over using internal drivers myself.
Few thoughts for you
Regards.
A
Hi Alan, Thanks for the reply.
Yes i would of liked to set Vref lower on the 2208’s but they are limited to 1v max setting, and with the calculations that did not even make the 1.5A of the motor. The actual stepper quoted out at 1.7A so i was way under than max torque, the need for white space speed is for reducing travel time laser off, on its journey across the x axis. it makes a massive difference to total time, on image burns acceleration also playing a big part.
I would like to go bigger steppers like some 23’s but, then with the white space scan speed of 16,000mm/min there would be a lot of extra inertia loading up the holding of the motors on direction change. so decided to stick with the 17’s and milk them for all they are worth.
I know I can not achieve more than 12,000 mm/min with 12v through the board, and have read in several places that the cnc 3018 boards don’t do 24v too well, and yes everything is well cooled with heat sinks and fans and the steppers also have heatsinks.
Ill defiantly give the 8825’s a blast with 24v supply, but the TB6600 can dish out up to 4A, just that they have had mixed reviews on life and skipping steps, the extra current so say should help with cooling so them in the know say.
But knowing the 8825’s are a lot quieter than the 4988 is a big pull and a lot less involved in moving over to external drivers.
