Pipe Mill Machine problem with D425

Hello all:

We have Pipe Mill Machine.

We use flyingsaw system with Simotion D425 integrated Sinamics.

We have problem with synchronous between External Encoder and Carriage Axis when various speed change (+) or (-) suddenly .

For example :

if machine speed 30 meter/min change suddenly to 60 m/min , big difference in tube length.

Hello,

obviously your drive can´t follow the leading axis.

Maybe your drive is on the torque limit already, or the dynamic limitation in the SIMOTION is set to small.

Zako

This is not Simotion's fault.

To at least help, try to do some work on the other end to limit the rate of change of the master speed (ramp time or acceleration).

If this cannot be done, then just accept the issue as scrap. Tell the machine operators that when they change the speed abruptly like this, they'll get scrap. (Cause and effect).

Like for example you can't travel back in time to anticipate a sudden change. If you've got 10 parts going through just fine at a stable speed on a conveyor belt, and your coworker (a bully) shoves the 11th part a few inches over just as you're about to put a tool on it, of course you're going to miss your target!

You could look at tightening up the tuning, or look at any acceleration or velocity limits, but more often than not, abrupt changes in line speed are going to cause scrap due to the mechanical design limitations and physics limitations.

Another thing you can do in this specific situation is monitor more of the systems signals to more intelligently react:

For example to possibly cancel the cut before it starts if there is an ongoing emergency stop. (A category 1 stop). This at least prevents material waste, but the operators would need to intervene to physically reset the work area.

Or to only allow the master to change line speed in a certain area when the saw is not cutting and to be done changing speed before the cut starts.

The censor filter makes my last post seem more profane.

It's censoring a 5-letter word for "wasted material".

zako_

Hello,

obviously your drive can´t follow the leading axis.

Maybe your drive is on the torque limit already, or the dynamic limitation in the SIMOTION is set to small.

Zako

Thank you very much to your reply.

I think that my settings of drive torque limits and dynamics response of axis are ok .

Drive torque limits are +/- 500 N.m .

Acceleration limits of axis are +/-40,000 mm/s2  with jerks of +/-10,000,000 mm/s3.

Attached mechanical structure system.

And what Trace tool says? How do the signals look like during the deceleration phase? I.e.: input position and speed on the External Encoder object, position and speed at its output and position and speed at the carriage axis.

As the EStop is concerned. Are you sure that the carriage is following the material movement until material feeding is standing still? Or maybe it gears out earlier due to response to EStop ?