100 ton four-column hydraulic press slow down!
The descending stage should generally be an oil return process, that is, the hydraulic oil flows back from the oil cylinder to the oil tank. The reason for the slow action at this time is that the valve core is not in place or the oil filter is blocked. If it does not move, it is probably because the new valve core is not thoroughly cleaned. Clean with diesel oil, apply vaseline, replace the oil filter and try again.