May 20, 2019, 06:59:32 AM
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 Asyncronous External Axis Drives keeps getting damaged - KRC4

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May 23, 2018, 03:07:03 PM
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Hi All,
 Let me explain the problem: We have a Blow molding machine which has 2 external asynchronous axis on a single linear guide which are controlled by a KRC4 KSS  8.3 controller. The Drives on the Linear guide keeps getting shredded and the internal tooth gets damaged every other week. The Motor teeth seems to be fine, only the internal Drive teeth seems to be shredded and completely damaged. This has happened on both the External axes. We have already built the same kind of machine with KRC4 before and the other machine seems to working absolutely fine. I did a trace of the Torque on the External axis which i will attach.
 We are looking into the possible mechanical alignment issues and measuring the linearity of the external axis. But at the same time i would like to make sure if the parameters of the External axis has been properly setup. I did a compare of the Machine.Dat from the other good machine, all the parameters match exactly. Except 3 of the following parameters:
$BRK_DEL_EX = 20000  (the working machine - 200 )
$OPT_TIME_PTP = FALSE (the working machine - TRUE )
$EKO_MODE = #ON ( the working machine - #OFF )

Can any of these parameters cause such drastic issue with the Drives getting damaged? if not is there any other parameter which i might need to double check?
I would also like to check if there is any parameter which defines the overall weight on the External axis? because the weight on these each axis is around 900 KG which i am not sure has been set in the parameters.

Thanks a lot in advance.

Today at 06:59:32 AM
Reply #1



May 24, 2018, 01:42:40 PM
Reply #1


Global Moderator
Wow.  Those traces look VERY nasty.

There's no parameter for the "weight" on the external axis, since any such axis could be built in completely unpredictable ways.  Instead, there are values for tuning the Proportional and Integral responses of the axis ($G_VEL_PTP, $G_VEL_CP, $I_VEL_PTP, $I_VEL_CP).  These need to be tuned using the Oscilloscope until the responses are smooth.

$RAISE_TIME might also bear looking at.  And if you're having many E-stop events, $RED_ACC_EMX and $DECL_MB come into play for how violent the braking is.

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