Is it mandatory in printing packaging films machine ?

[munzir]

Is it mandatory in printing packaging films machine that the speed signal / frequency reference command / input frequency reference (i.e. DC voltages) of the in-feed drive (vfd) equals to out-feed drive (vfd) & also for the unwind drive (vfd) the speed signal / frequency reference command / input frequency reference (DC voltages) keeps on increasing as the diameter of the film (web) keeps on decreasing & for the Rewind drive (vfd) the speed signal / frequency reference command / input frequency reference (DC voltages) keeps on decreasing as the diameter of the film (web) keeps on increasing ?

 

[betwixt]

You win this weeks prize for the most ambiguous question. :???:

I'm trying to understand what you are asking and I think you are saying "does the diameter of the film on it's spool make the motor rotate at a dfferent speed", if so the answer is yes, However, I would think it unlikely that the spool speeds were controlled in a way that adjusted them according to diameter. More likely, the speed of the feed mechanism is controlled so the image speed is constant, the feed spool has a light braking control to maintain feed tension and the take-up spool has light pulling action to ensure constant tension on the output spool.

Brian.

 

[chuckey]

I think that the light braking action is done with a constant torque motor.
Frank

 

[betwixt]

On multi-track audio tape systems I've worked on in the past, each motor simply had a diode and resistor in series across the motor supply. The idea being that when the motor was 'dragged' around by unwinding tape, it behaved like a loaded generator. The diode conducted and the resitor provided the load and hence breaking action. The take up spool motor had it's torque controlled by a current limiter circuit.

Brian.

 

[munzir]

i think my question is simple ........ there ain't no ambiguities

 

[FvM]

I think it's mandatory, that the speed of both roll drives varies relative to the film feed rate.

In other words, your question is simple and clear except for these points:

- Is the film feed rate constant?
- What's the implemented control method for both roll drives?
- Does the machine use tension sensors to control the drives?
- Does it use constant speed or constand torque motors for roll drives

 

[kak111]

I agree with FvM

printing packaging films machine that the speed signal / frequency reference command / input frequency reference (i.e. DC voltages) of the in-feed drive (vfd) equals to out-feed drive (vfd) & also for the unwind drive (vfd) the speed signal / frequency reference command / input frequency reference (DC voltages) keeps on increasing as the diameter of the film (web) keeps on decreasing & for the Rewind drive (vfd) the speed signal / frequency reference command / input frequency reference (DC voltages) keeps on decreasing as the diameter of the film (web) keeps on increasing ?

So is this all mandatory i dont know , some machines some parts of these must be or some others part of these are control options. ? ? ? ? ?

 

[munzir]

i have worked with some of the older & a new printing machine , both have the same principle of providing the input command signal to the drives from the PLCs .....

The voltages (input command signal) that are generated continuously by the PLC to the drives i.e. for in-feed & for out-feed remains same from the start to the end of the packaging film web roll .....

while in the beginning the packaging film web roll on the unwind (has the larger diameter in terms of rewinding) so its voltages (input command signal that are generated continuously by the PLC to the drive) keeps on increasing as the diameter of the packaging film web roll on the unwind keeps on decreasing while of the rewinding it keeps on decreasing as the diameter of the film web roll keeps on increasing (so PLC's input command signal to the drive keeps on decreasing)

Also all the motors except for rewinding runs in reverse (rewind) position , the drive shows negative frequency (frequency with negative sign) & Reverse direction on its digital operator panel , rewinding motor runs in forward direction and hence the drive displays on its operator that its running in forward direction and has the positive sign with the measured frequency.