we have an issue with press machine. Hydraulic part of machine is created by pump with ind. motor, proportional valve and controlled by rexroth card. Regulation is in closed loop and deviation between "sollwert" and "istwert" is during process in tolerance.
The problem is with motor - pump system and shaking during regulation.
We changed motor, pump, changed Rexroth hydraulic card and setted up, prop. valve, feedback cable and sensors but without success.
When the proportional valve is changed by manual valve without feedback, shaking is smoothed.
Is here anybody who can help me??