CNC shield stepper not working correctly

Other Hardware Motors, Mechanics, Power and CNC
1

Hi there!

Im currently building a new CNC machine and somehow I cant get the steppers work correctly.

Have a look at this video:

I send a simple commands to the motor. Z0 and Z5. The motor is very loud and as you see in thr video, the motor makes a stop for a short period of time before it finishes the motion.

The shield is running GRBL.
Its not a mechanical problem as the leadscrew moves without problems.

What am Im doing wrong? I tested the coils of the motor and the wiring seems to be correct.

Anything obvious I did wrong?

Thank you very much in advance!

2

It sounds like the motor shaft is spinning inside the coupling. Is the setscrew tight on the flat part of the shaft?

3

Also ensure the axis has not got any major resistance along its full length of travel before coupling up to the stepper.

Make sure you have also grease loaded the bearings prior to assembly unless they are the plastic IGUS type.

Also check your acceleration / deceleration settings.

4

it is probably bed connection to motor and loudness is from wrong current setting.
hope it is not damage of one coil in the motor

5

Thanks guys for your fast replies!

I dont think its a mechanical problem because have a look:

There is no coupling at all and the problem persists. Maybe the drivers are broken? Tried all 4 and everytime the same. Also tried another stepper. Same here.

Acceleration settings: what could go wrong here? I have 10 mm/s here.

Full steps btw! No microstepping enabled yet.

6

give G1 Z50. do you able to hold the shaft with hand or motor is too powerful for it?

i don't know how you set the longitude of STEP impulse, it should not be shorter as in datasheet of motor recommend.

7

The result for g1 z50:

Since the motor stops in the middle of its move, I cant find out if it lets me stop it unfortunately :frowning:

8

Can you clarify this a little? The motor is a 42BYGHW208 Nema17 stepper. I cant find any reference to the step impulse and where to set it in GRBL?!

9

clamp shaft with your finger. try to stop it.
if you can hold then it definitive broken connection.

10

Have you seen the video two posts above for g1 z50? For the time the motor spins I cant stop it, no. It stays still for a few seconds by its own before it finishes the motion.

11

ok. good.
give G1 Z5 F50

12

The motors spins very slow (of course) and loud but it moves all the time, no stopping.

13

how small step dividing is set? 1/16?

14

Its currently set to full step as Im waiting for my jumpers in the mail... :wink:

15

i see. the problem is in length of step pulse to driver, its too short.

16

Okay I see! In GRBL its just $0 and $1 settings I have to adjust?

For example $0=20 microseconds maybe?

17

I can't find a maximum rated speed but from the sound and movement in the video it looks like you are trying to move it faster than it can move. Try setting the maximum speed lower. F50 (50 steps per minute?) works. Try doubling the speed (100, 200, 400, 800...) until the problem comes back. Then you know that the maximum speed is between the last two speeds.

18

yes, make both doubled.
and show us entire settings screen.

19

post #11

The feedrate per minute of the move between the starting point and ending point

20

Here are my settings directly from a working machine.
Clearly you can ignore some of them

$0=10 (Step pulse time)
$1=25 (Step idle delay)
$2=0 (Step pulse invert)
$3=0 (Step direction invert)
$4=0 (Invert step enable pin)
$5=0 (Invert limit pins)
$6=0 (Invert probe pin)
$10=1 (Status report options)
$11=0.010 (Junction deviation)
$12=0.002 (Arc tolerance)
$13=0 (Report in inches)
$20=0 (Soft limits enable)
$21=1 (Hard limits enable)
$22=1 (Homing cycle enable)
$23=1 (Homing direction invert)
$24=25.000 (Homing locate feed rate)
$25=300.000 (Homing search seek rate)
$26=250 (Homing switch debounce delay)
$27=5.000 (Homing switch pull-off distance)
$30=1000 (Maximum spindle speed)
$31=5 (Minimum spindle speed)
$32=1 (Laser-mode enable)
$100=800.000 (X-axis travel resolution)
$101=800.000 (Y-axis travel resolution)
$102=400.000 (Z-axis travel resolution)
$110=1500.000 (X-axis maximum rate)
$111=1500.000 (Y-axis maximum rate)
$112=450.000 (Z-axis maximum rate)
$120=25.000 (X-axis acceleration)
$121=25.000 (Y-axis acceleration)
$122=15.000 (Z-axis acceleration)
$130=165.000 (X-axis maximum travel)
$131=270.000 (Y-axis maximum travel)
$132=100.000 (Z-axis maximum travel)