Noobie Settings for Chinese YooCNC Ebay router

My machine doesn't sound very good or cut to the correct scale with my current configuration.

I bought a chinese ebay machine with YooCNC drivers. I like the machine, but I am having difficulty with this.

These are the specs from my machine's very stingy manual:


Leadscrew 1404 double thread Trapezoidal screws

Driving units X axis 1404 trapezoidal screws
Y axis 1404 trapezoidal screws
Z axis 1404 trapezoidal screws

Sliding units X axis Dia.16mm chrome plate shafts
Y axis Dia.16mm chrome plate shafts
Z axis Dia.12mm chrome plate shafts

Stepping motor type 57 two-phase 1.8A
Principal axis collet ER11 / 3.175 mm
Repeat accuracy 0.05mm


I need to determine the correct timing settings for the stepconf wizard such as:

Leadscrew Pitch
Driver Microstepping
Step Time
Step Space
Direction Hold
Direction Setup




Can anyone help?

Thanks

ok , here i go but i will admit to guessing as information on this is sketchy at best
also as you dont mention the actual machine or controller model numbers

4mm pitch
400 steps per rev ( standard stepper motors 200 steps per rev x half step )
10us step time
and 5us direction hold

the YooCNC is a very basic Allegro chipset controller , most of the default settings should get you somewhere in the ball park
see how you go , and we can smooth out the wrinkles as you find them .

Yep more info would be better. As cncbasher pointed out default settings for Step and Direction is a good starting point.
The micro stepping setting would be on your driver set by a jumper or switch possibly.

But if the machine is working (steppers can be noisy at low speeds) try this,

Set your machine for a known move, say 1"
mark your starting point on the table.
Set a slow speed (F5)
Take any backlash out (G1 X-1)
Go to start position
(G1 X0)
Move 1" (G1 X1)
Measure how far the machine moves.
Calculate the difference between what the machine moved and what you commanded.
Use that to calculate your true scale. If you commanded a 1" move and the machine moved .5" you are off by a factor of 2.
Go back to Stepconf and adjust what you need to to get the Scale you need entered and test again.

Also test your machine by moving positive and negative from a know location to see if you are losing steps.

Rick G

Perhaps cruxfixture can let us know what settings hit the sweet spot. Good, bad or indifferent; quite a few people are buying these machines and their larger brethren.

Thank you for everyone's help, I have the machine working better now. I am getting very accurate dimensions, but travel still sounds funny, not smooth like before. I hear a faint knocking sound during travel, especially when velocity is slow. This could derive from bad latency?

My StepConf Settings are as follows:

-Step Time and Space: 10us(10000ns)
-Dir Hold and Setup: 3us

These are based on the numbers given in my manual, but I am not sure if this is correct.

Base Period Max Jitter is 50us, but when I run the latency test I can get as high as 330us of Base thread Max Jitter.

X axis settings:

Motor steps per rev: 400 (Explicit in Manual, I am pretty sure that this is correct)
Pulley teeth: 1:1 (I think this is right since I don't see any gear reduction)
Leadscrew Pitch: 4 mm/rev (I turned the axis one rev manually with power off and measured the distance traveled)
Driver Microstepping: 4 (I don't think that this is correct, but This is where I had to use trial and error and it gave me the correct distance)

Max. Velocity: 33mm/s ( Explicit in Manual)
Max. Acceleration:200mm/s2 (EIM)


Other axes are identical expect for slower Max. velocity on the Z.

Base Period Max Jitter is 50us, but when I run the latency test I can get as high as 330us of Base thread Max Jitter.

Well that does not sound right, take a look here at the info on Base period and Stepconfig...

linuxcnc.org/docs/html/config_stepconf.html#cha:Stepconf-Wizard

Do you get an error code when you start EMC?

If you enter the proper latency number in Stepconfig it will calculate the best Base period you can use. That will determine how fast your motors can be run from EMC, if the motors are up to it.

Motor steps per rev: 400 (Explicit in Manual, I am pretty sure that this is correct)

A typical stepper motor would have 200 steps per rev, so at 1/2 stepping would be 400 steps per rev.

Pulley teeth: 1:1 (I think this is right since I don't see any gear reduction)
Leadscrew Pitch: 4 mm/rev (I turned the axis one rev manually with power off and measured the distance traveled)
Driver Microstepping: 4 (I don't think that this is correct, but This is where I had to use trial and error and it gave me the correct distance)

It does not really matter how you input the numbers in Stepconfig as long as the resulting steps give you the Scale you need. So 400 motor steps and 4 micro stepping is the same as 200 motor steps and 8 micro stepping.

Stepper motors can be noisy at slow speeds, there is a normal slow speed band that can be quite a bit rougher than other speeds. You need to check that you are not losing steps by making several moves back and forth and making sure you end up where you started.


Rick G

if the manual is saying 400 steps then the correct settings are 200 steps x 2 as i said earlier , or in other words it's running in half step microstep mode as the majority of stepper motors are 200 steps per rev
you may find the Max velocity and Acceleration values can be set different to what is in the manual , just go with what sounds right or gives you no lost moves , a lot of performance and pc latencey can affect these as Rick G says

it's usual for the Z axis to be probably around half of the Max velocity as this axis has the weight to carry and is also fighting against gravity , so slightly less performance in using steppers is ok
again so long as your not loosing steps and all sounds good is fine