Troubleshootings for Power Press
You are here: Home » Support » Tutorials » Punching Machine » Troubleshootings for Power Press

Troubleshootings for Power Press

Views: 2704     Author: Site Editor     Publish Time: 2020-08-21      Origin: Site


With the increasing progress of industrialization, the popularization of power press and other equipment has become more and more widespread, so various types of punching problems have also increased. Here is a brief explanation of the common mechanical failures and maintenance of power press.


Because the power press has the characteristics of fast speed and high pressure, certain safety regulations must be followed when the power press is used for punching and forming.

⒈ The transmission parts exposed to the outside of the press must be equipped with a protective cover. It is forbidden to drive or test drive with the protective cover removed.

⒉Before driving, check whether the main fastening screws are loose, whether the mold is cracked, whether the operating mechanism, automatic stopping device, clutch, and brake are normal, and whether the lubrication system is blocked or lacks oil. If necessary, you can drive an empty car for testing.

⒊When installing the mold, the slider must be opened to the bottom dead center, the closing height must be correct, and the eccentric load must be avoided as much as possible; the mold must be tightly fastened and tested by pressure.

⒋Attention must be concentrated during work, and it is strictly forbidden to put hands and tools into the danger zone. Small pieces must be operated with special tools (tweezers or feeding mechanism). When the mold is stuck on the blank, only tools are allowed to release it.

⒌It is found that the press is running abnormally or there is abnormal sound, (such as battering sound, popping sound), stop feeding immediately, and check the cause. If the rotating parts are loose, the control device fails, and the mold is loose and defective, stop and repair it.

⒍ Every time you finish a workpiece, your hands or feet must leave the button or pedal to prevent misoperation.

⒎ When there are more than two people, you should order someone to drive and pay attention to coordination. Before leaving get off work, the mold should be dropped, the power supply should be disconnected, and necessary cleaning should be carried out.

Troubleshootings for Power Press


⒈ The crankshaft bearing heat may be caused by bad scratching of the sleeve.

⒉ Insufficient lubrication needs to check the lubrication condition and re-grind the copper tile.

⒊ There are copper chips in the oil flowing from the bearing, which may be due to lack of lubricating oil or unclean lubricating oil; at this time, check the lubrication condition and disassemble the bearing for cleaning.

⒋The guide rail burning may be caused by too small guide rail clearance, poor lubrication, poor contact, etc.; it is necessary to re-grind the guide rail or adjust the clearance, and then pay attention to lubrication.

⒌ During operation, the clutch cannot be combined or cannot be disengaged after being combined. It may be that the spring of the slewing body has lost its elasticity, or the two springs are too tightly matched; at this time, replace the spring or scrape the combined gap of the button.

⒍ When the clutch is disengaged, the slider cannot stop at the top dead center position. It may be due to insufficient tension of the brake band, excessive wear of the brake band, oil slippage on the brake wheel, etc.; need to adjust the brake spring tension, replace the brake, or wash with kerosene Net brake belt and wheel circumference.

⒎If the return plate does not work, it may be caused by the wrong position of the punching head. You need to adjust the position of the head to turn the flywheel to try back.

⒏ Rotation or impact of the connecting rod screw may be that the locking device is loose, and the locking device needs to be rotated.

⒐ The impact of the ball head of the connecting rod screw in the ball pad of the slider may be due to poor contact between the ball head and the ball pad gland or the gland screw is loose; it is necessary to scrape the ball head, the ball pad, and tighten the gland screw.

⒑ Pressing the button (on) does not work, it may be that the power supply is cut off, the thermal breaker is cut off, and the circuit system needs to be checked to eliminate the fault.

Troubleshootings for Power Press

Correction methods

⒈The gap between the slider and the guide rail: The gap adjustment is mainly for accuracy, and heat will be generated when the adjustment is too tight. Generally, each side of a minicomputer is 0.02~0.05mm, and each side of a mainframe is 0.03~0.20mm.

⒉ The method of correcting the integrated gap: touch the moving slider body by hand during production. When the slider reaches the bottom dead center, there will be a sense of vibration, indicating that the integrated gap is too large and needs to be adjusted in time.

⒊ The locking of the sliding block connecting rod: due to long-term use or overload, the connecting rod will loosen. This state is generally considered to be an overload; in addition, oil leaching at the joint may also be overloaded; this The state must adjust the locking degree of the connecting rod lock nut in time, because this is related to safety issues.

⒋ Maintenance of brakes and clutches: The brakes and clutches of presses are important parts for the safe operation of presses. They are the cause of major safety accidents. Therefore, it is necessary to understand its basic structure and confirm its safety performance before daily operations. , Find abnormal conditions (such as: the slider can not stop at the specified position, abnormal sound during operation, abnormal vibration, slow slider action, etc.) promptly report maintenance. In addition, maintenance personnel should also pay attention to if the gap between the brake and clutch friction plates is too large, the performance is: the amount of compressed air increases, the press slider appears to crawl, and in serious cases, there will be a continuous operation of the slider. , This is absolutely not allowed to happen. Then if the adjustment gap is too small, the friction linings of the brake and clutch will generate friction noise, heat, and the motor current will rise, and the return spring will also be damaged. (The normal clearance standard is 1.5~3.0mm).

Troubleshootings for Power Press

⒌ Disengagement: The disengagement phenomenon generally occurs at the bottom dead center. When the upper and lower molds are closed, the slider cannot operate normally. At this time, the motor can be reversed and the air pressure can be increased. The operation selector button can be set to the "inch" state, and the slider can be pulled up to the top dead center in stages.

⒍ Correction of bolt loosening: it includes the bolts of machine tool ancillary facilities, which must be confirmed regularly, especially for some high-speed and frequent press machines, because the vibration of these machine tools is relatively large and the bolts are easy to loosen. Once the bolt is loose, if it is not corrected in time, it will cause some unexpected safety accidents.

⒎ Spot inspection of the oil supply device: The operating part of the machine often suffers burns and bites when the oil is not supplied in time, so the spot inspection of the oil supply part must be carried out reliably. It includes the oil cup, oil tank, oil pipe, filter, oil seal, etc. "running, emitting, dripping, leaking, blocking" phenomenon must be dealt with in time.

⒏ Compressed air inspection: When the compressed air pipeline of the machine tool leaks, the pressure will be low, which will affect the operation of the machine tool, and the machine must be repaired in time. In addition, the water content of compressed air should also be controlled (an air filter, drying and dehydrating device can be installed), which is a major cause of slow motion and corrosion of machine tool solenoid valves, cylinders and other devices.

⒐ Regularly check the accuracy of the punch: the accuracy of the punch will directly affect the service life of the mold and the processing accuracy of the product. However, the accuracy of the machine tool deteriorates over time, so it is necessary to conduct regular accuracy inspections and repair problems in a timely manner to ensure that the machine tool has a more precise accuracy, thereby ensuring the accuracy of the products produced.

Troubleshootings for Power Press

Common failure causes and solutions

Fault location 1: Transmission system
Failure phenomenon Cause of failure Troubleshooting
Large transmission noise. (1) The air pressure of the balance cylinder is too low or high. Adjust the air pressure of the balance cylinder.
(2) Foreign matter is caught in the transmission pair. Foreign body removal.
(3) Gear or bearing wear. Remove for repair.

Fault location 2: Clutch brake
Failure phenomenon 1 Cause of failure Troubleshooting Remarks
The temperature of the friction plate of the clutch and brake rises abnormally, and the friction piece wears faster. (1) The clutch air pressure is too low, causing the friction surface to slip, leading to heat and wear. Adjust the clutch air pressure, and check whether the pressure relief valve and the pressure relay on the beam are malfunctioning. If damaged, need to be replaced.
(2) The actions of the clutch and brake are not coordinated, that is, the brake has not been disengaged and the clutch has been closed; or the clutch has not been disengaged, and the brake has been applied. Adjust the action time of the pressure safety valve for the clutch and the pressure safety valve for the brake, to ensure that the brake is quickly aired in, quickly exhausted, and the clutch is slowly aired in and quickly exhausted to ensure coordinated and reliable actions of the two. If both valves are damaged, they must be repaired and replaced.
(3) Damaged seals, air leakage or pipeline air leakage. Replace the sealing ring and repair the pipeline.
(4) The friction plate is stained or has foreign objects caught. Remove foreign objects or replace friction block. The friction block must be of equal thickness.
Failure phenomenon 2 Cause of failure Troubleshooting Remarks
Braking angle is too large (exceeding the range of top dead center) or too small (not reaching the range of top dead center). (1) The compression spring is damaged. Replace the spring.
(2) The safety valve of the press before the brake air intake is stuck or damaged. Repair or replace the air valve.
Failure phenomenon 3 Cause of failure Troubleshooting Remarks
When the clutch is engaged, the slider runs slowly and an exhaust sound occurs on the front service station. The safety valve of the press in front of the brake inlet is malfunctioning or not energized. Repair the solenoid valve and check if the solenoid valve circuit is well wired.
Failure phenomenon 4 Cause of failure Troubleshooting Remarks
After pressing the two-hand button, the double valve will act immediately and then stop. Double valve failure (press safety valve for clutch, press safety valve for brake). Check whether the double valve wiring is good and restore it. After repairing, use the key switch on the button panel to reset the double valve fault. Only then can start again.

Fault location 3: Slider parts
Failure phenomenon 1 Cause of failure Troubleshooting Remarks
Mounting height can not be adjusted or the air switch of the motor will trip when it is activated (1) The air pressure of the balance cylinder is too low or too high Adjust the air pressure of the balance cylinder
(2) There is a foreign body stuck in the lifting screw Clean up dirt
(3) Wear and tear of lifting screws and nuts Repair or replace the lifting screw nut
Failure phenomenon 2 Cause of failure Troubleshooting Remarks
Slider overload protection system pressure can not go up (1) Low oil level in fuel tank Add some oil Oil for overload protection tank N32
(2) The suction pipe of the pneumatic pump is loose and leaking Seal and tighten the suction pipe
(3) Garbage enters the pneumatic pump, so that the inlet and outlet check valves cannot be closed Cleaning the pneumatic pump
(4) The system leaks oil, or the hydraulic cushion seal is damaged Detect oil leakage, repair or replace parts and accessories
(5) There is air in the unloading valve of the pneumatic pump Unscrew the bleed screw on the unloading valve to deflate Refer to the unloading valve manual
(6) The fuel tank filter is blocked Cleaning the filter
Failure phenomenon 3 Cause of failure Troubleshooting Remarks
Pneumatic pump keeps pumping oil Same as above Same as above
Failure phenomenon 4 Cause of failure Troubleshooting Remarks
Compression machine appears stuffy car and slide block and die
Press the slider manual unloading button

Fault location 4: Lubrication
Failure phenomenon 1 Cause of failure Troubleshooting Remarks
Lubrication pressure is too low, the lubrication pressure alarm light is on (1) Lubrication pump filter is blocked Clean or replace the filter Change the lubricating oil and clean the oil tank if necessary
(2) The spool of the overflow valve is stuck Clean or replace the overflow valve
Failure phenomenon 2 Cause of failure Troubleshooting Remarks
The lubrication pressure is too high, the lubrication pressure alarm light is on (1) The piston of the chip oil separator is stuck Cleaning the slice oil separator Change the lubricating oil and clean the oil tank if necessary
(2) The spool of the overflow valve is stuck Same as above
Failure phenomenon 3 Cause of failure Troubleshooting Remarks
Lubrication flow is too low, lubrication flow and lubrication pressure alarm lights are on (1) Caused by too low lubrication pressure Same fault 1 Lubricating oil N100 (large oil tank)
(2) The piston of the chip oil separator is stuck Cleaning the slice oil separator
(3) The oil outlet of the slice oil separator is blocked at a certain point or several points Check the signal rod of the differential pressure indicator on the main oil separator. If the signal rod protrudes, it means that the oil outlet of this road is blocked or has a large damping. Check the lubrication point of this road to eliminate the fault If the faulty oil path passes through the oil separator, check whether the valve core of the sub oil separator is stuck or the oil outlet pipe is not unblocked.

Fault location 5: Main motor
Failure phenomenon 1 Cause of failure Troubleshooting
The main motor button is pressed but not started (1) The air switch of the main motor is not closed Close the air switch
(2) The lubrication pump is not turned on or the lubrication is faulty Turn on the lubrication pump
Failure phenomenon 2 Cause of failure Troubleshooting
The motor stops suddenly during operation Lubrication failure Turn on the lubrication pump


Get A Quote


Copyright  2023 Nanjing Harsle Machine Tool Co. Ltd. All rights reserved.