[rodw]

Hi,
whether we like it or not the largest share (75% plus) of CNC components are metric.

If want the widest range of products from the widest range of manufacturers to secure the best price/performance trade-off then metric is the best choice.

Craig

Might I add that is because there are only three countries remaining in the world who still persist with imperial measurments. And in those countries the majority of engineering is done in metric.

[joeavaerage]

Hi,

And in those countries the majority of engineering is done in metric.

Quite so. While I think of linear measurements in mm's, weight measurements in kg's....I still think about pressure in pounds per square inch....and torque in foot pounds.
You'll have to talk to my alter ego as to whether I'm schizophrenic or not.

No matter what happens as soon as I start doing ANY engineering calculations I'm all metric, and MKS....none of the CGS confusion either...as much as I like the unit of Erg....ERG...ERG,
it just such a great name! Anyone who proposes to substitute Erg for Joule gets my vote.

I'm doing a conversion for a customer on a largish guillotine. He had already purchased some Parker AC servos, a 900W one and a 200W one, but had no drives for them.
The cost of one Parker 900W drive cost more than two complete Delta B2 servo kits (750W and 400W) which include servo, drive and cables, and included shipping.
Why would anyone bother with US made stuff? Its just not that damned good.

Craig

[Sray]

A twig-thin shaft is definitely a source of weakness in the drive. If you go with 23's, I'd suggest going with the 3/8" shaft versions as a minimum.

Yeah I was very disappointed when I went to order my Nema 23s to find that they are 6.35mm instead of 8mm like many Nema 23s. I was hoping to go with the 24s because the ones I were looking at were 10mm but in the end they would not have worked in my setup. So I am sure that I will be upgrading the motors in the future.

All comes down to budget, and I blew way past mine. So I will have to make it work for a while.

I did end up getting the 2 disc/diaphragm couplings instead of the spiral kind.

[dazp1976]

Yeah I was very disappointed when I went to order my Nema 23s to find that they are 6.35mm instead of 8mm like many Nema 23s. I was hoping to go with the 24s because the ones I were looking at were 10mm but in the end they would not have worked in my setup. So I am sure that I will be upgrading the motors in the future.
All comes down to budget, and I blew way past mine. So I will have to make it work for a while.
I did end up getting the 2 disc/diaphragm couplings instead of the spiral kind.

Pity about the shaft size.
As long as you get it in level it shouldn't be too much issue. Mainly keep an eye out for any coupling slip.

If you want to get decent performance the initial budget always goes out the window.
I assume it is the motors you need to wire in parallel to get the best results.

[joeavaerage]

Hi,

Pity about the shaft size.

Who bloody cares! If you are direct coupling to the ballscrews there is no radial thrust. If however you are using pulleys and belts then there is radial thrust for which
increased shaft size prevents undue armature flex. A 1/4 inch shaft will handle all the torque your steppers can drum up....do you suppose the manufacturer
would go to all the trouble of making a motor only to put too small a shaft in it? I don't think so.

Craig

[pippin88]

Hi,


Not a lot, or rather it takes some force to deflect them from straight. Given that the size of my ballscrew and servo shafts are substantial that's fine.
With your much smaller steppers and ballscrews you'll want flex but at lower force levels, I should imagine the smaller size couplings would do just that. You want
double discs as they provide for axial mis-alignment in two planes, rather than single disc.

The bellows types are good but if there is substantial mis-alignment the repeated flexing causes them to break eventually. I suppose the double disc types could break eventually,
I've been using them for several months....no problems thus far.

Despite the minor torsional flexure the spiral cut ones are perfectly good as well, and cheap as chips.

Craig

I've broken one double disc coupler

Had a ticking sound that I assumed was ballscrew for ages, but was actually the steel disc in coupler - had fractured.

The double disc are much much better than the aluminium spiral (aka spring) couplers

[joeavaerage]

Hi,

The double disc are much much better than the aluminium spiral (aka spring) couplers

I agree, and said as much....but what I also said was that the spiral coupler in effect provided a 'fuse' and despite the torsional flex I found
the advantage that should I ever crash the coupler would shear rather than wreck my machine. Over the six and a half years I operated my
min-mill I used three couplers as replacements...and I bought six originally so no further expense was encountered. They cost a whole $12.00
including postage when I got them. I can recommend them on the basis of price/performance, not withstanding there are better designs.

Craig

[Sray]

So I was contacted by stepperonline telling me that the motors I want are out of stock. They asked if I wanted a dual shaft instead. Is there any issue with getting the dual shaft motors?

[Sray]

Or maybe I should look for a 8mm or 10mm shaft motor to replace it with? Not sure I can find something with equivalent specs (400+ oz.in/1.8mH) the same price point ($45/each) though?

[JohnZ]

If the dual shiaft motor is the same specs, go for it. That shaft can support an encoder, or a damper to reduce harmonics or vibrations. I'll get a photo of one I have on an old machine.

Sent from my SM-G991U using Tapatalk

[Sray]

If the dual shiaft motor is the same specs, go for it. That shaft can support an encoder, or a damper to reduce harmonics or vibrations. I'll get a photo of one I have on an old machine.

Sent from my SM-G991U using Tapatalk

That is good know. Thanks!

Definitely interested in seeing a pic.

[Sray]

Quick question. I found these Nema 24s that look like a decent step up from the 23s I originally ordered. The cost is a little bit more ($53 total) but I think the specs of this motor are worth it.


Holding Torque: 3.5 Nm(495.74oz.in)
Rated Current/phase: 5.0 A
Phase Resistance: 0.48 ohms± 10%
Inductance: 1.85 mH ± 20%(1KHz)
Shaft size: 10mm

The inductance is close to the 23s (1.8 mH). The torque is 25% more. And the 24s have a 10mm shaft vs the 6.35mm of the 23s.

Am I overlooking anything here or do these look like a better option?

[dazp1976]

Quick question. I found these Nema 24s that look like a decent step up from the 23s I originally ordered. The cost is a little bit more ($53 total) but I think the specs of this motor are worth it.
Holding Torque: 3.5 Nm(495.74oz.in)
Rated Current/phase: 5.0 A
Phase Resistance: 0.48 ohms± 10%
Inductance: 1.85 mH ± 20%(1KHz)
Shaft size: 10mm
The inductance is close to the 23s (1.8 mH). The torque is 25% more. And the 24s have a 10mm shaft vs the 6.35mm of the 23s.
Am I overlooking anything here or do these look like a better option?

I did actually link you those in post number 5.
Best I've seen on their site in terms of 23/24 sized motors imo.

Again:
https://www.omc-stepperonline.com/ne...m-4-wires.html

[Sray]

I did actually link you those in post number 5.
Best I've seen on their site in terms of 23/24 sized motors imo.

Again:
https://www.omc-stepperonline.com/ne...m-4-wires.html

Thanks for the reminder.

I also found them on oyostepper.com. I am sure they are the exact same motors.

[JohnZ]

That is good know. Thanks!

Definitely interested in seeing a pic.

Here is the dampener I mentioned. It mounts to the back shaft on a NEMA 23 motor, but I moved it to the other end of the screw as a thumb-screw for manual adjustment on this machine. (Telescope mirror polisher)

This appears to be liquid filled and some sort of magnet inside. It damps vibrations on the motor, reduces noise, and seemed to increase max speed on the motor.

Sent from my SM-G991U using Tapatalk

[dazp1976]

Thanks for the reminder.
I also found them on oyostepper.com. I am sure they are the exact same motors.

They do indeed look the same.
They're also on Aliexpress:
https://www.aliexpress.com/item/4000...c00OkgyOh&mp=1

What I've found on Ali is that if I order 1 at a time I can get snail mail delivery to the u.k.. Usually get through customs easy via this route.
If I order 2+ of them at once I am only offered Fedex which always hammers me for a ridiculous customs sum.
Also was cheaper buying 1 at a time.

Didn't check options on oyostepper.com

I'd have these motors too but I'll go for servo next.

Right now I have the equivilent of these wired parallel:
https://www.oyostepper.com/goods-95-...m-8-Wires.html
Responded well with 60v even with the 3mh level.
Stepperonline didn't have the 495.74oz listed at that point.

[dazp1976]

I'm doing a conversion for a customer on a largish guillotine. He had already purchased some Parker AC servos, a 900W one and a 200W one, but had no drives for them.
The cost of one Parker 900W drive cost more than two complete Delta B2 servo kits (750W and 400W) which include servo, drive and cables, and included shipping.
Why would anyone bother with US made stuff? Its just not that damned good.
Craig

All your fault!!!!!.
I'm gradually starting to save for servos. Looking at 400w + 750w fo PM25 size mill. Peak/rated figures roughly seem equual to existting steppers.
Now.. I quite like the Lichuan A4 1.8kw I have already + familiar with the wiring now so looking at theirs but....
The encoder count/ inductance// resistance levels don't really impress. (likely be fine though).
Now looking at more expensive Delta's with about 17bit 160,0000 couunt and around 6mh area.
I did see a 24bit 16,777,216 count unit. Could I even set that up on a UC300eth & UCCNC?.
I reckon 17bit is about enough for it.

[joeavaerage]

Hi,

Now looking at more expensive Delta's with about 17bit 160,0000 couunt and around 6mh area.
I did see a 24bit 16,777,216 count unit. Could I even set that up on a UC300eth & UCCNC?.
I reckon 17bit is about enough for it.

The Delta B2 series are more expensive than Lichuan, typically by about 25%. The upside is better documentation and really good set-up and tuning software. I have tried programming the drives
without the software but its just to time consuming and error prone, I refuse to do that any more.

Just because an encoder has 160,000 counts/rev or 1,280,000 counts/rev or more, that you have to use it all. Electronic gearing allows you to set the required input pulse rate to
achieve a certain angular movement of the servo.

For example I have set the electronic gearing of my servos (numerator/denominator) such that 5000 input pulses ie Step pulses, causes one revolution of the servo. At 5000rpm
that requires a Step pulse rate of 416kHz....which is entirely fast enough.

Craig

[Sray]

Here is the dampener I mentioned. It mounts to the back shaft on a NEMA 23 motor, but I moved it to the other end of the screw as a thumb-screw for manual adjustment on this machine. (Telescope mirror polisher)

This appears to be liquid filled and some sort of magnet inside. It damps vibrations on the motor, reduces noise, and seemed to increase max speed on the motor.

Sent from my SM-G991U using Tapatalk

Thanks for the info/pic.

[Sray]

Here is the dampener I mentioned. It mounts to the back shaft on a NEMA 23 motor, but I moved it to the other end of the screw as a thumb-screw for manual adjustment on this machine. (Telescope mirror polisher)

This appears to be liquid filled and some sort of magnet inside. It damps vibrations on the motor, reduces noise, and seemed to increase max speed on the motor.

Sent from my SM-G991U using Tapatalk

Thanks for the info/pic.