So the cylinder may have not been filling fast enough. Would that cause a shorter packet?
As to it creeping by .006 per stroke. If the cylinder was not evacuating fast enough, pressure might increase at each stroke, less fluid movement per stroke. But at some point it should have become a steady mis measure, till reset might relieve the build up.
I suspect that when the machine was shut down, the inlet valve to the cylinder defaulted to closed, the outlet valve defaulted to open.
I did install larger pumps but I did not change the size of the plumbing I believe it was relatively low pressure I think it was under 500 PSI operating pressure the pump would put out considerably more than that
Then I think the flow rate was not up to the cycle rate. Probably due to the valves. 50 to 70 is quite a big percentage increase. That is pretty much my last guess. It is the most obvious variable that does not rigidly, mechanically scale to increased speed of operation. Also the valve actuation time remains the same. Open time can be varied, but time to open and close is pretty much static. This also limits speed of operation overall. Actually, pressure increase can also change actuation time open, close, or both.
Oh I forgot. Are the valves electrically activated or mechanically? If mechanically, then the open close time scales to the overall mechanical speed of the system. But flow rate can still drop off at higher speeds. If electrically activated, then you do have the added problem of static open/close time.
I see the valves are solenoid activated. So there is a definite time interval to fully open and close that will not scale with increased cycle rate.
From my single course in process control, (I’m instrumentation and electronic) I recall that decreasing speed of a system will make it more stable. The question would be whether stoppages at the higher speed would produce more product than operating at a slower speed,
In this particular instance we were actually doubling the speed they had been operating on 13 of the 15 machines operated flawlessly so we were able to actually triple production because it better maintenance and things like that so overall it worked out very well.
Very cool.
Sometimes, but it very much depends on the details. A bicycle is a system that gains stability at higher speeds (within limits).