Moving Flow Control Closer to the Cylinder Causes Problems

By Robert Sheaf, CFPAI/AJPP, CFPE, CFPS, CFPECS, CFPMT, CFPMIP, CFPMMH, CFPMIH, CFPMM, CFC Industrial Training

A customer had a system that required the vertical cylinder to accelerate at different speeds caused by different models of steel bumpers they were forming. They could adjust the cylinder’s force remotely but had to climb under a table to adjust the downward speed. They found that both speed and cylinder’s tonnage adjustments for the different-sized bumpers decreased their scrap.

The customer decided to fully open the meter-in flow control on the valve stack controlling the downward speed. They installed a line-mounted valve next to the pressure control to increase the operator’s convenience and safety, as well as reduce the time to convert die changes.

The counterbalance valve was located next to the valve stack and the outlet of the new flow control was plumbed directly to the cap end of the cylinder. However, they had problems with the cylinder’s downward stroke shuddering and had to adjust the counterbalance valve to eliminate the new problem.

Any idea what caused the new problem?

See Solution