Recommended pulley's for Delta printer

Falkia

Any recommendations for the pulley size for a delta printer (16 or 20 teeth)?

Bed size: D500mm

Motors are Nema17, 42BYGHM810.
Step Size: 0.9°
Rated Current: 2.4A
Rated Holding torque: 4200gcm
Resistance: 0.8Ω
Inductance: 1.8mH
Detent torque: 220gcm

Thanks
Fredrik

Veti

it depends on the sliders you are using.
the belt path should match the diameter of the pulleys

Falkia

@Veti the printer is under design so the width of the belt path can be chosen but it looks like it will be 18mm

Veti

you will have to make the decision as to what you want.

16 tooth. lower top speed, higher accuracy compared to 20 tooth.

on my corexy i use 16 tooth pulley, on my delta i use 20 ( because of the sliders otherwise i would use 16)

dc42

There are several consideratoins:

As @Veti says, you should make sure that the rest of your mechanics is compatible with whatever pulley size you choose.
Assuming GT2 belts, at x16 microstepping the steps/mm will be 160 using 20 tooth pulleys, or 200 using 16-tooth pulleys. So slightly better resolution per microstep using 16-tooth pulleys (5um) vs 20 tooth pulleys (6.25um). Also, 5um is easier to work with than 6.25um when measuring Z probe trigger heights.
The full step resolution will be 100um using 20 tooth pulleys, or 80um for 16-tooth pulleys. Some users prefer to use a layer height that is a whole number of full steps; in which case 100um is easier to work with than 80um.
20-tooth will allow a slightly higher speed than 16-tooth before you run out of either VIN voltage to counter the motor back emf, or step generation rate

If using 1.8deg motors then I think it's worth using 16-tooth pulleys to get better resolution. With 0.9deg motors, I don't think it makes much difference. I started off using 20-tooth pulleys and 1.8deg motors, then changed to 16 tooth pulleys for better resolution. But then I changed to 0.9deg motors. I still use 0.2mm layer height even though it is not a whole number of full steps.