Are taper lock pulleys a good choice for ball screws?

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Originally Posted by dazp1976

Even with motors of near the same inductance is proven.
Nema34, 1080oz (7nm and change) 3.5mh inductance:
Loud, bad resonance, max velocity 2000mm/min, stalls thereafter, Inertia causes 0.2mm overshoots at stop.

Nema24, 566oz (4nm) 3mh inductance:
Near silent, max velocity can exceed 3000mm/min, stops dead, accels like a rocket.

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And here I thought it was all down to inductance.

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Originally Posted by dazp1976

Still have a 1080oz on Z, (2000 is quick enough there). Might need it for my spindles new servo motor (7kg weight)
Upping the power to 72V, might change driver to a stepperonline 100vdc input one (psu can go to 80).

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Which drivers are you considering?
I have the CL86Y or CLA86T from stepperonline on my list of options for this project.
I could run them directly off 60VAC

Taperlocks are used extensively in industry, I have made my own using ER collets, pic of one on my bench mill and one on my router, both driven by servos

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Originally Posted by Muzzer

Personally I wouldn't consider the additional moment of inertia of a taperlock pulley to be a massive concern if you have a long 20 or 25mm ballscrew but if you have steppers, I guess you may struggle with speed and response as it is. Without a high drive (power supply) voltage, the torque output of steppers quickly tails off, so the headline torque figure may be misleading.

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Surprisingly it does Muzzer.! . . Esp with a stepper system on long screws and smaller steppers feel it the more and really struggle with it if the pulleys are heavy. This is why when building machines with long screw lengths and steppers, (over 4ft) I select a higher pitch screw and use a ratio to lower screw speed, this serves 2 purposes, lowers the chance of screw whip and lowers the inertia.
I also only fit Nema 34 motors which use high voltage drives, often these are at mains voltage depending on motor size 8nm + but for the smaller 34's I still wouldn't use drives less than 80Vac/100Vdc. The 4.5Nm and 5.5Nm Nema 24 Closed loop Lichuan motors I use now are so powerful running on 60Vac that I rarely fit Nema 34's below 8nm as the difference they allow in performance is much better.

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Originally Posted by JeffZ

And here I thought it was all down to inductance.



Which drivers are you considering?
I have the CL86Y or CLA86T from stepperonline on my list of options for this project.
I could run them directly off 60VAC

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Need to do more research but the CL86Y atm.
I'm still pondering about going closed loop later down the line. If this can run in open loop as well (for the time being), then I'll get it right now.

Otherwise it'll be the DM860Y as the machine sits, and then I'll look again at a later date if I change to CL.

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Originally Posted by JAZZCNC

The 4.5Nm and 5.5Nm Nema 24 Closed loop Lichuan motors I use now are so powerful running on 60Vac that I rarely fit Nema 34's below 8nm as the difference they allow in performance is much better.

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Are you referring to the LC60H2102, LC60H2112, LC60H2127 series motors?
They were my preferred choice initially, and I only removed them from my list of options because shipping was close to 200€ for 4 motors (from the Lichuan aliexpress store).
Are you driving them using the Lichuan LCDA86H drivers?
My original plan was to run 4xLC60H2127 + LCDA86H at 60VAC.

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Originally Posted by JeffZ

Are you referring to the LC60H2102, LC60H2112, LC60H2127 series motors?
They were my preferred choice initially, and I only removed them from my list of options because shipping was close to 200€ for 4 motors (from the Lichuan aliexpress store).
Are you driving them using the Lichuan LCDA86H drivers?
My original plan was to run 4xLC60H2127 + LCDA86H at 60VAC.

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Yes, the LC60H2102 and LC60H2127 with LCDA86H drives for the Nema 24. For the NEMA 34's I use the 10Nm LC86H3156ZB 3 phase motor with LCDA2260E 220V drive.

I buy them in bulk (100sets) and have them custom built with 5mtr cables and also have the annoying 15pin Dsub connectors removed. I ship them via Sea so the cost is lower but yes shipping via Air freight is expensive these days.
For UK builders I offer to supply them, along with UCCNC controllers, WC-spindles, etc but given Brexit and the EU situation I don't really want to get into sending outside of uk due to export hassles.

The other thing to think about is for an axis with double ballscrews you need to be able to square the gantry. This might mean being able to rotate one ballscrew very slightly by hand (without the pulley secured) until the gantry is square, so a key way or D flat would not work as this puts the pulley at a fixed location on the ballscrew. A simple pair of grub screws allows the pulley to sit at any angle on the ballscrew.

Also on the inertia side I did the calculations for machine design years ago and the mass of the gantry was a pretty small part of the motor requirements. The acceleration of the ballscrew was a large part of the motor requirement, and this in turn related to the ballscrew inertia. Inertia relates to having mass a long way from the axis of rotation, so heavy pulleys will have an effect. If you want to pocket them out then removing mass furthest out makes the biggest difference. And larger pulleys are significantly worse as inertia relates to the square of the radius so goes up quickly.

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Originally Posted by routercnc

The other thing to think about is for an axis with double ballscrews you need to be able to square the gantry. This might mean being able to rotate one ballscrew very slightly by hand (without the pulley secured) until the gantry is square, so a key way or D flat would not work as this puts the pulley at a fixed location on the ballscrew. A simple pair of grub screws allows the pulley to sit at any angle on the ballscrew.

Also on the inertia side I did the calculations for machine design years ago and the mass of the gantry was a pretty small part of the motor requirements. The acceleration of the ballscrew was a large part of the motor requirement, and this in turn related to the ballscrew inertia. Inertia relates to having mass a long way from the axis of rotation, so heavy pulleys will have an effect. If you want to pocket them out then removing mass furthest out makes the biggest difference. And larger pulleys are significantly worse as inertia relates to the square of the radius so goes up quickly.

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If I had the knowledge and tools I'd prefer to drill/tap a longish threaded hole into end of the ballscrew and bolt on a pilot bore pulley. Use say 5mm high tensile. Guess it depends on machine size wether it would hold.

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Originally Posted by JAZZCNC

Yes, the LC60H2127 with LCDA86H

I buy them in bulk (100sets) and have them custom built with 5mtr cables and also have the annoying 15pin Dsub connectors removed. I ship them via Sea so the cost is lower but yes shipping via Air freight is expensive these days.
For UK builders I offer to supply them, along with UCCNC controllers, WC-spindles, etc but given Brexit and the EU situation I don't really want to get into sending outside of uk due to export hassles.

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Interesting. How do you feel about supplying just 2 of those 2127 sets?

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Originally Posted by dazp1976

Interesting. How do you feel about supplying just 2 of those 2127 sets?

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Yes no problem, I'm low at the minute and can't spare the current stock I have but I have another batch arriving in around a week's or so (they are actually arriving in port about now so should clear customs and be with me in about 7 days of landing.)

I'll PM you when they arrive.