[qingwokou7]

I’m thinking about Using closed loop stepper motors and drivers in 3d printer. If any of my axis have two stepper motors, I will connect them parallel. Is same possible with closed loop steppers, since they have encoders attached???

https://www.oyostepper.it/goods-1264...3-Nema-24.html

[Toinvd]

I don't think you can. Putting two motors in parallel will work, putting two encoders in parallel won't work.
You could use two drivers and two motors and put the input to the drivers parallel.
However, if a 3d printer is missing steps, I would first look at the mechanical stuff like binding of a axis or using a to high speed.

[peteeng]

Hi Qing - Connecting motors in a parallel has issues. I presume by your statement that you want to connect two motors from one driver. Since your making a printer use a printer controller board. Much easier and generally they have many drivers so each motor will have a separate driver. If you connect two motors from one driver the interference of the motors will mean the electronics of the driver will not be able to control them properly especially at high speed. I have tried a couple of ways to do this and the results are very poor. Printers these days need speed and so you will need one driver per motor. Look at Big Tree tech boards. Cheaper then CNC systems and they have all the correct temperature controls and other stuff needed by a printer. Good Making... Peter

[joeavaerage]

Hi,
for decades prior to closed loop steppers being available open loop steppers were used to complete satisfaction. The only time an open loop stepper misses steps is if its overloaded,
thus if you correctly specify the open loop stepper for a particular application then it will never miss steps. Where then is he advantage of closed loop?

All steppers lose torque the faster they go, closed loop or open loop makes no difference. The manufacturers of closed loop steppers say 'goes faster, more power, never misses steps'.....all BS.
It is true that if a closed loop stepper being marginally overloaded and it misses a step, the drive will insert an extra step to catch up......but guess what, that extra step is just as likely to be missed as the regular step
Closed loop steppers can interpolate between steps in a manner that open loop steppers cannot, and so have more resolution, and can of course fault out m if it misses steps which it cannot recover rather than continuing making a misshapen part,
so they do have advantages.....but not enough to justify the cost.

I would suggest buying top quality, LOW INDUCTANCE open loop steppers with at least 80VDC drivers and not concern yourself with closed loop.

Closed loop is more marketing hype than truth.

If you really want 'closed loop goodness' then get AC servos. AC servos eat any stepper ever made....just a shame they are as expensive as they are. I use 750W Delta B2 series servos
and they are superb, and have such a generous overload ability you'd swear they were 3hp....not 1hp!

Craig

[phomann]

Hi,
for decades prior to closed loop steppers being available open loop steppers were used to complete satisfaction. The only time an open loop stepper misses steps is if its overloaded,
thus if you correctly specify the open loop stepper for a particular application then it will never miss steps. Where then is he advantage of closed loop?

All steppers lose torque the faster they go, closed loop or open loop makes no difference. The manufacturers of closed loop steppers say 'goes faster, more power, never misses steps'.....all BS.
It is true that if a closed loop stepper being marginally overloaded and it misses a step, the drive will insert an extra step to catch up......but guess what, that extra step is just as likely to be missed as the regular step
Closed loop steppers can interpolate between steps in a manner that open loop steppers cannot, and so have more resolution, and can of course fault out m if it misses steps which it cannot recover rather than continuing making a misshapen part,
so they do have advantages.....but not enough to justify the cost.

I would suggest buying top quality, LOW INDUCTANCE open loop steppers with at least 80VDC drivers and not concern yourself with closed loop.

Closed loop is more marketing hype than truth.

If you really want 'closed loop goodness' then get AC servos. AC servos eat any stepper ever made....just a shame they are as expensive as they are. I use 750W Delta B2 series servos
and they are superb, and have such a generous overload ability you'd swear they were 3hp....not 1hp!

Craig

Saved me a whole lot of typing.
Couldn’t agree more.

Cheers

Peter.