[hmu64]

Our Error description (Mazak SQT 18 MS, 1996):

Processing stops sometimes with alarm messages, especially in the morning during the first working hours of the day:

Alarm 21 Power drive fault (1, 0, &0023), followed by Alarm 204 (Spindle Controller Error)
or
Alarm 24 Overload (1, 0, &0052)

According to our observations, alarm 21 occurs mainly during normal turning and alarm 24 during machining with powered tools.

According to the documentation, the first alarm refers to a speed (revolutions) that deviates from the setpoint and the second alarm refers to a position of the axis that deviates from the setpoint when activating the servo drive. The "1" in the parentheses indicates the spindle drive as source for both alarms.

If the machine is restarted after one of these alarms, it usually continues to work without any problems. These errors no longer occur, especially in the afternoon.

Sometimes several days or a few weeks go by without this problem occurring. Then it comes again - for no apparent reason.
However, the frequency of errors appears to be increasing in recent months.

We have now also found another error in the history: Alarm 355 (Start Cond. Err., C-Axis OFF)

Any ideas / tips?

Thanks a lot, Holger

[hmu64]

Today we had a variation of the error.

- The machine stopped working in the middle of the current program and the spindle was standing still.
- We could turn the spindle / chuck by hand freely.
- But at the same time the spindle load bar in the machine display showed changing values between 100% and 120%.

Than, after a few minutes, the error 21 came up like before.

It is irritating that the machine is sometimes working for a few days without a problem, but than the error comes back again.

Any ideas?