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Splines self-align under tension provided the tangential load is within tolarance. It seems to me that using set screws will interfere with this. In my experience splines are usually held in place...

Yes, friction coefficient doesn't change. Generally minimum hole depth will be determined by the shear strength of the threads though. Longer bolt has more shear resistance. More shear resistance ->...

Stepper motors are rated in RMS Current. So normally you would set the driver to 3A rms in half-coil. In Bipolar series you would use 2.1A rms.

However 48V is quite a lot of volts for a 1.6mH...

Your formula is correct. A 2mm pitch screw gives a significant leverage advantage, hence the large resultant force.

Have you ever changed the tire on a car? A standard car jack works identically...

Measure the resistance of each coil with an ohm-meter. They should all be the same i.e around 0.6 ohm. Quite likely that one of the coils has burnt out.

I think you have an error. The forumla in cell B13 reads, "=E2*(B2/1000/2*PI())^2", but it should be "=E2*(B2/1000/2/PI())^2"
The difference is a factor of pi^4 ~= 100, in the calculation of the...

If it is still there it shows it is the steppers. Forces change when cutting, so could still be steppers if vib isn't there.


Hot isn't required. Check driver current if you can.

If nothing...

I've looked through many data sheets in recent times. My impression is that the bottom dollar chinese motors (eg ebay, web shops) often use invented numbers for values like torque. If you are lucky...

Well if you do put a flywheel on your spindle make sure it is carefully balanced. 24k rpm is not a good time to discover the mass you bolted to your shaft is ever so slightly lopsided.

Seems like...

Nice. Good to see wood being used on a large machine without sacrificing rigidity.

I'm interested to know what steppers you are using and whether you are using any reduction gearing on the x&y...

Reducing the current setting on the driver should bring your temperatures down.

It was the current setting I was interested in. Your motors in series need ~2A, but in unipolar they need 3A. Thats 3A rms which I believe is the maximum setting on your m542 drivers.

Hmm. Kind surprised the unipolar/series difference was that noticeable. Did you increase the current when changing to unipolar?

Those motors are selected to work with cncrouterparts linear drive solutions. CNCRouterparts sell rack'n'pinion and 5-start screws, both of which are much faster than your screws.

If i'm not...

Ah ok, 54mm motors. Still nice motors though.

They are rated 3A? So they are probably based on the PKP266U3 rather than the PKP266U2. So that would be 1.33mH in unipolar and 5.32mH in series.
...

Interesting. Are they really 2.99inch (76mm) long? They look a bit shorter in the photos.
Did you wire them half-coil (unipolar) or series?

I wish we knew the inductance, they look like very nice...

Nice. Now if only we knew what inductance and torque those motors have we could learn something. :)

Glad it is working out for you. That is good precision.

I'm surprised at the large jump in speed. Perhaps the bottle neck is the number of pulses per second that you can get to the driver.

Which steppers to use will depend on the screws. Screws can give a significant leverage advantage and so you might consider much smaller faster motors.

Serious designs of this size often use two...

Full step can speed you up a small amount, ~40% in theory. You will still be very very slow though at 56mm per/minute.

The real problem here is M8 screws, which travel ~1mm per revolution.
Also I...

I would not be comfortable at 48V on these drivers. To close to the rocks with a cheap switching supply at the helm.

For another $30 you potentially try a faster motor instead. There is a popular...

That 50Vdc rating on your drivers is probably a peak rating. It's considered healthy to leave room for power input fluctuation and back EMF. I wouldn't be comfortable above 44V, particularly with...

I could be wrong, but isn't this the calculation of your maximum lift:

1kg ~= 35oz so 175oz/in = 5kg/in

8cm shaft = 3.15 inch

Max lift = 5/3.15 = 1.59kg

Edit: oh, are you trying to lift...

I'd be interested to know how those drivers work out for you. Wantai has a mixed reputation.

Leadshine make a m860, datasheet is here:
http://www.leadshine.com/UploadFile/Down/M860m.pdf

Looks like 2.5mH motors. They will happily take all the voltage your drivers can cope with, 30-35v might be helpful, again depending what speed you want.

Whether your motor can lift Z depends on...

Thanks for the answers. So many variables, so many questions. I see why most copy for their first build.

Yeah, more volts. Could stack 2 Atx in series for 24v.

The answer depends on the number of amps/mH your motors are rated at though and how fast you want to spin them.

Ah, thanks, good to know at least one person has done this successfully. I take it that it is always better to run bipolar parallel over uni-polar, even if you don't bump up the current, the...

I would cut/draw a square wave right across the x axis in 1 inch steps (after calibrating for 1inch). Then draw/cut a straight line next to it. Final result should look something like the attached...

I was wondering if it is possible or practical to take apart 6-wire stepper motors and rewire them to be bipolar parallel? The theory seems simple enough if the connection points are accessible. Has...