Losing steps on closed loop stepper motors

Hello,

I have build a 3-axis cnc using IHSS60-Closed-Loop stepper motors with on board drivers.
I did some first milling and realized that I am loosing steps (Position of the tool after the milling is off by up to 0.5 mm from the position before the milling.
It cannot come from backlash because I measured that and it is really low (so the ballscrews and the mounting seems ok)
Therefore I guess that the machine is somehow loosing steps.
However I do not understand how a closed loop motor can loose steps. I've tried to change the settings (increase step-time, reduce micro stepping to a longer step-time) but it does not change. One possibility I thought of is that the cables (which are not shielded) may produce some fake steps from noise maybe?
Or has anybody some other idea what could be the problem?
Thanks in advance for any hint.

Hi
does the Driver firer its Error
if not it is Mechanical
but you can reduce FOR Testing
the Speed to 50%
in ini
the ACC to 75% of its setting
the 60Volt low level Closed are not that fast responding so increse the Stepscale and speed also direction by 500ns

then check again
did you set the SCALE realy as it is

and also using the stepper parameters 400/600/1600 microsteppings not the 1000/2000/5000 as of encoder space

I would try

STEPTIME 5000
STEPSPACE 5000
DIRSETUP 10000
DIRHOLD 10000

As marginal timing is a common cause of missed steps.
I would also verify that you have the step polarity correct
because incorrect step polarity can cause a violation of the
direction hold time.

@bbsr_5a
no, there are no errors indicated on the driver.

I have also reduced the speed and acceleration for testing and it seems a bit better, but there still is an error.
And an error from acceleration should (like classical step skipping) should not be possible for closed loop motors?

The scale of the axes (microstepping , leadscrew pitch and so on is right since the error only accumulates over time, but a single distance is the length it is supposed to be. What do you mean by "and also using the stepper parameters 400/600/1600 microsteppings not the 1000/2000/5000 as of encoder space"

@PCW
first i had following settings:

STEPTIME 5000
STEPSPACE 5000
DIRSETUP 20000
DIRHOLD 20000

I've already changed that to

STEPTIME 10000
STEPSPACE 10000
DIRSETUP 25000
DIRHOLD 25000

but that did not make any differnence

Excessive acceleration should not cause step loss (though might cause a drive fault)

Did you try inverting the step pulse?

Is it on all axis or just one ?
Is everything mechanically tight ?
Is it a linear error, ie does it change with distance tested or is it a constant error of Xmm ?

What type of coupling between the lead screw and motor are you using ?

What type of bearings are you using for the lead screw ? Does the fixed end use angular contact bearings or regular bearings ? Is the fixed bearing tight in it’s housing ?
What procedure did you use to check for backlash ?
Are your lead screws clean with no crap on them ?
What kind of lead screw and nut are you using ?
Is the error the same when you start at different positions along the length of travel ?