Lichuan 4 axis stepper need help-

Hakan wrote:

It can be that the motor speed needs to be ramped up, like it is by linuxcnc.
Setting 6000 rpm as a step is quite challenging.
Anyway, 3000 rpm is more than decent for a stepper motor.

Consider to use csp mode, that's what most people do.
The position feedback is lagging two servo cycles when using ethercat
and a velocity loop has a hard time.

If you use csp, the position update will stop in your scenario, and the motors will stop.
Check out the SDO listing, there is a max current setting (per motor).

 

If I got my math correct, target velocity 500000 = 3000rpm, target velocity 600000 = 3600rpm

>needs to be ramped up...
Yes, another detail I failed to remark on: I noticed when operating in opmode 9 this drive uses a sane accel/decel rate, which kind of surprised me.
I can change target velocity in big jumps and it ramps smoothly to my target velocity. But if I set controlword = 6, the addressed motor stops BAM!
If I set target velocity first, then controlword = 15, it does not move. I changed target velocity to 0 then to 10000 then it started. Didn't check whether I actually had to set target velocity = 0 first.

As far as I can tell, in opmode 8, it behaves as you described. If I set position in any size of small or big jump, it tries to move there instantaneously. Small jumps move the motor, big jumps just make a "chirp".

>If you use csp,
Good idea. I just had to play with my new toy.image missing /media/kunena/emoticons/wink.png

NWE wrote:

 
I know the motor's phase inductance or voltage rating can make a huge difference in top speed attainable. These motors do not have either of those specs listed, making it harder to compare specs, but when I get a chance, I'll try to measure phase inductance.

Higher inductance motors need higher voltage to produce the same speed and torque. This is the first thing that comes to mind, seeing what these motors can do.
sed with steppers, the ones I previously used would never have got this speed on 24V, hardly even at 48V.


 

During COVID, I worked with Marshall, a US engineer as we were going to design a plasma table together. He (mostly) and I (the tester) developed an insanely comprehensive spreadsheet model that benchmarks a stepper drive for current consumption, voltage requirement ambiant heat generation. We wanted to utilize stepper motors insane low down torque for acceleration which we thought trunped a geared down servo (which is a lot easier to design for).
If you can find these specs, mainly inductance, I'll run it over your drive.
 
I ran countless NEMA 23,24 and 34 motors through this model.
I then validated his model by replacing motors on my plasma table with those that passed the spreadsheet test. 

After testing countless motors, For all that is said about low inductance, We busted that myth. Some of the better performing motors had quite high inductance. Rotor inertia seemed to be more imortant.
Some failed because they needed too much voltage (beyond what you could buy a power supply for,
Others failed because they drew to much current (above the motors rated amps),
And some failed because the estimated ambiant temperature eise would have melted the wiring (which is  usually rated at  about 130 deg C)
This particular Sanyo Denki has insanely high rotor inertia and weighs accordingly! I speculated that the reason this was limited to 2 amps was because there simply wasn't enough room left in the drive for heavier wire! On my plasma table X axis, I achieved 60000 mm/min rapids and 8000 mm/s/s acceleration with a 30mm dia pinion and 3:1 gearing. I paid about $20 AUD per drive on eBay and another $10 for the wiring harness. After this testing, I saw the guy had a few left and bought the lot. the RRP of the drives is still around AUD $250. They run silently as smooth as silk.

So I had a few left and thought I'd better use them. I have some DM542a stepper drives here I could have used but my pc doesn't have a parallel port so by the time I bought a card and breakouts or even a Chinese 7i92, I might as well buy a multiaxis Ethercat drive.

Anyway, that's why I am here. My next step is to check I have phase polarity correct. I have a feeling I might have changed something early in the piece trying to get things to work because I know these drives deliver.

I found some specs for my LC60HS112 motors in the catalog:
model: LC60HS112
step angle 1.8
holding torque 4.0NM
rated current 4.0A
phase resistance 1.56 ohms
phase inductance 3.9 mH
rotor inertia 1200 g.cm2
motor weight 1.807 Kg
shaft dia. 8mm

Here are details on my motors that don't match the above catalog specs to some degree:
motor weight 1.79 Kg
shaft dia. 10mm

I messaged Lichuan to see what they say.
 

There you go. I've spent a few hours today updating this to add cutting forces as it was initially built for plasma table design.I don't know what kind of machine you are planning but I have put it beside my drive X (yours is Y, Z ignore.)This is based on the work energy method and assumes a 3 second cut with a 1% trapezoidal profile. eg 1% accel,  (98%) cruising and 1% decell at a cut speed of 5000 m per minute. 150 N cutting forces. Assumes a 45mm dia pinion (40 tooth Mod 1.25 gear) with 5:1 gearbox they don't seem to make a 30mm (20 tooth) pinion for a 14mm dia output shast which is the normal  one found on a planetary gearbox.It draws a trapezoid profile of the test cut.I almost left your power supply at 24 volts as it actually would do the job for those specs. I put a derating to 24v in and it shows no reduction. But it halves the available power to the same as my 2 amp motor @ 48v. So the sheet goes through all of the physical power and torque requirements

We calculate motor Average power and RMS power. I would use Average power with cutting forces. This number must be less than the available power  lists further down

So we can see that your drive under these conditions only needs 2 amps RMS at 22 volts. Further up there is a magic ratio, the System to Rotor Inertia Ratio. It should be 1:1 but not exceed it. In your case, its massively oversized for my project. And so is mine but the price is right.

Finally, we calculate the ambient heat rise. It must not exceed the drive's rating which is usually around 130 deg C when the insulation could melt. SO you can see that is not an issue and that 100deg C is usually safe.

So all in all both motors simply idle and will never be called upon to exceed their available power at which point you could loose straps. SInsummary, they can run 24/7 without the risk of loosing position!

Thanks, Rodw, looks great! image missing /media/kunena/emoticons/smile.png
I really need a bigger faster 3d printer, my Elegoo Neptune Max gantry type printer doesn't always fit my projects... I'm inspired by an FLSUN S1 that I watched printing one day. It runs delta kinematics, and it runs so fast the print head is just a blur. Pretty much sounds like a clothes washer in fast spin cycle when it's printing.

I'm playing around with dimensions a bit. In my 3d sketch, the linear rails are 2000mm long and will be attached to the steel frame (not shown). The round build plate at the bottom is 750mm diameter. The delta legs carrying the print head will likely be aluminum round tube.

It will be enclosed and heated, build plate will also be heated. The three delta motors will be up on top outside the heated enclosure, driving the carriages up and down via gear belts.

The door will be something like polycarbonate. Two thirds of the sides will be sheet metal heavy enough so it doesn't sound like a tin can, that steel shell will probably be the main frame. One third of the sides will be the clear door spanning most of the distance between two rails.

I do not yet have any mass measurements for calculating speeds with. I will be happy if I can make it go faster than my Elegoo printer. I don't expect to win any races with that FLSUN S1, that thing looked like its delta legs might be carbon fiber.

Well if you think about it, the delta winch drum is really the same as a pinion drive in relation to motor analysis,
So no cutting forces, 2 kg axis weight (actually that's way wrong as the print head has 3 wires supporting it) but it did not make much difference.
I have no real idea here but if you want speed, grab a 48 volt 10 amp power supply (for 3 motors) a 2:1 reduction gearbox and a 60mm diameter winch drum, and you are good for 37,000 m/min!

The limiting factor here was the voltage and this needed 46 volts. if they had a drive good for 72-80 volts like rtelligent you might crack 40 m/min  revised Report attached. Some early runs did not get past 12 m/min until I started tweakimg drums and gearing.

I'll be very interested to see how you go as I thought seriously about making one to but had no experence. Beckhoff have some interesting modi;e to read the cool stuff printers need!