Printed from Kezuriba (kezuriba.net/en/maintenance/press/troubles/)

Press troubleshooting quick reference

Look up likely causes, what to check, and remedies from the symptom. Inspection intervals, acceptance values, and oil types follow the press manufacturer's manual and the nameplates on the machine and safety devices first. The specified self-inspection is done by a qualified person or a registered inspection company. Mounting and adjusting safety devices is work that requires special training. The legal points here were checked on 2026-10-06 against public materials from e-Gov and the Ministry of Health, Labour and Welfare (MHLW), so watch for amendments

Stopping position drifts, or the time to stop gets longer (loss of stopping performance)Mechanical press

Stopping angle when stopped at one stroke, and maximum stopping time on a stopping-performance measuring device^[6][1]

Likely cause	What to check	Action
Wear of the clutch and brake linings, increase in pressure plate stroke	Pressure plate stroke, lining wear amount	Service the press to bring it back to its original stopping time. Replace linings with manufacturer-specified ones^[1][2](1 source, for reference)
Too many intermittent operations, so the brake overheated	Number of intermittent operations (per minute) and the machine's allowable intermittent SPM	Use within the allowable intermittent SPM. The higher the slide speed, the more heat is generated at stopping, and the lower the allowable countIf the heat generated by stopping cannot be released every cycle, the brake warms up and causes loss of stopping performance and heating problems (AIDA)^[3](1 source, for reference)
Low air pressure for the clutch and brake, or a faulty solenoid valve	Operating pressure of the pressure gauge and pressure switch, air supply/exhaust noise and operation of the solenoid valve	Return the pressure to the manufacturer-specified value. Replace the solenoid valve (AIDA's guide is 5 years in continuous use, 3 years in single-stroke use)^[2][4][5]
Oil on the friction surface of a dry brake	Oil on the lining	Fix where the oil is getting in, and replace the lining^[4][2](1 source, for reference)

Product dimensions vary with the time since start of operation or with the seasonMechanical press

Likely cause	What to check	Action
Bottom dead center displacement from machine heating and room temperature change	Trend of the bottom dead center position since start of operation (it drops at first, then rises after about 30 minutes). Whether airflow from heating or cooling is hitting the machine	Do not let air conditioner airflow blow directly on it. Stabilize it with warm-up and the temperature setting of the oil temperature control unit^[7](1 source, for reference)
Loss of static accuracy, eccentric load	Measure accuracy by the JIS B 6402 items, and check the position of the die's load center	Restore the static accuracy with regular maintenance. Reduce the eccentric load^[7][8](1 source, for reference)

Blanking dies wear or chip a lot, and blanking noise and vibration are largeMechanical press

Likely cause	What to check	Action
Breakthrough (the shock when the press, which had been deflected, springs back all at once the moment the material fractures). It is larger the greater the total clearance in the joints	Total clearance of the upper and lower joints, size of the bolster drop-out hole	Apply an opposing force with a movable stripper. Make the bolster drop-out hole smaller, or widen the lower die's bearing surface with an insert plate. Restore worn clearance by overhaulIf left alone, it leads to damage to the slide, connecting rod, and crankshaft, wear on the back side of the main gear teeth, loose bolts, and cracks in the frame (AIDA)^[9][8](1 source, for reference)

On a servo press, work that used to be possible can no longer be done. It stops on overvoltage during deceleration or stoppingMechanical press

Likely cause	What to check	Action
Degradation of the energy-storage aluminum electrolytic capacitors (lower capacitance, higher internal resistance, electrolyte leakage)	Bulging of the pressure valve (visual), capacitance with an LCR meter	Replace with press-specific capacitors. An annual inspection is recommended (AIDA)^[10](1 source, for reference)

The slide of a hydraulic press drops under its own weight even though it is stoppedHydraulic press

Likely cause	What to check	Action
Fault in the slide drop prevention device	Amount of drop when stopped at the upper limit of work, automatic holding and release function	Ask the manufacturer to repair it. Support the slide with a safety block during repair^[2][4](1 source, for reference)
Damage or fatigue of the spring or spring seat of the main operating valve	Disassemble and inspect the main operating valve	Replace the springs, etc.^[2](1 source, for reference)

Hydraulic oil temperature rises, or the oil degrades quicklyHydraulic press

Likely cause	What to check	Action
Low oil level	Oil level gauge	Top up to the reference level and fix the leak^[11](1 source, for reference)
Dirty heat-transfer part of the oil cooler	Whether the oil temperature rises gradually after several months of operation	Inspect and clean the cooler^[11](1 source, for reference)
Water in the hydraulic fluid, or degradation	Emulsification, discoloration, and foaming of the oil; fluid property tests (kinematic viscosity, total acid number, water content)	Drain the tank. Change the oil once it exceeds the oil change criteria^[11][2]

Bearings seize, or clearances widen and accuracy fallsCommon

Likely cause	What to check	Action
Use of degraded lubricating oil, or poor lubrication	Lubrication condition of the lubrication system, oil replacement timing	Use the specified oil and replace it periodically^[12][2]
Use of unspecified oil (same viscosity but different additives)	Brand of oil in use and the oil specified in the manual	Return to the oil specified in the manual^[12](1 source, for reference)

A hand was caught by the slide even though a safety device was fitted (lesson from accident cases)Common

Likely cause	What to check	Action
The safety device was turned off and the selector key was left in	Keeping of the selector key, state of the safety device	The press work chief keeps the key. If the die and safety device interfere, consult the work chief and take another safety measure. Create work standards for abnormal and non-routine work^[13][14](1 source, for reference)
An arm slipped out from under the effective range of a light curtain starting device (PSDI) and started the press	Whether there are guards or a table above, below, and at the sides of the effective range	Provide guards above, below, and at the sides so that the body cannot leave the effective range. Fit a separate, effective safety device in addition to the starting device^[15](1 source, for reference)

Causes on the side of machining conditions and tools are covered in the Machining Troubleshooting Encyclopedia .

📚Sources

Items without a mark are those on which two or more materials from different publishers agree. Values and intervals are governed by each machine's specifications. The text is summarized in Kezuriba's own words.