Mechanical power presses are among the most widely used machines in the manufacturing industry. They can perform stamping, punching, forming, and other metalworking operations at high speed and efficiency. However, they are also classified as high-risk equipment because accidents can cause severe injuries such as amputations, fractures, or crushing incidents.
For this reason, every company that uses presses must strictly follow mechanical power press machine safety guidelines and provide comprehensive mechanical power press safety training to operators, supervisors, and maintenance personnel. This guide provides a detailed, step-by-step explanation of safety requirements, common hazards, protective devices, etc.
The Need for Mechanical Power Press Machine Safety
The importance of mechanical power press safety training lies in its ability to prevent the following types of injuries:
1. Mechanical Injuries
The primary hazards of mechanical power presses are mechanical injuries such as amputations of fingers, hands, or arms, as well as crush injuries and fractures. These often occur when an operator’s hand enters the danger zone, particularly during manual loading and unloading or when adjusting the die. Accidents may also result from operator fatigue or lack of focus, leading to errors in operation.
2. Hazards at the Point of Operation
The point of operation is the area where the operator is most likely to be injured, especially during the insertion, securing, or removal of materials. If safety devices fail or are not used correctly, the operator’s hands may be caught in moving parts, resulting in severe injury.
3. Equipment Malfunctions and Poor Maintenance
Equipment failure or improper maintenance can also cause accidents. For example, failing to inspect or service the machine regularly may result in loose, broken, or defective components, creating serious hazards. In addition, improper use of the press or failure to follow standard operating procedures can further increase risks.
4. Other Potential Hazards
- Sharp edges: Handling materials may cause cuts.
- Flying debris: Metal fragments produced during processing may strike and injure operators.
- Falling objects: Improper handling during die changes or equipment adjustments may cause heavy parts to fall, leading to injuries.
Power Press Machine Safety Responsibilities for Different Roles
Basic Responsibilities of Factory Managers
- Customize safety measuresaccording to your company’s specific processing and operational requirements, ensuring the most suitable protection methods are in place.
- Provide workers with asafe working environment and necessary protective equipment (such as safety helmets, safety glasses, gloves, and protective shoes) to shield them from hazards caused by points of operation, rotating parts, flying debris, sparks, and other risks.
- Ensure that throughout the entire production process, thepress machine is properly installed, adjusted, and equipped with functioning safety guards. It is strictly forbidden to modify or dismantle safety devices without authorization.
- Appoint designated responsible personnel, such as operators, die setters, and maintenance staff. No one outside these roles should be allowed to operate the press. Maintenance staff must be capable of performing ongoing, qualified maintenance.
- Before production officially begins, providetraining and assessment for all designated personnel, including responsible managers, operators, die setters, and maintenance staff, and confirm their ability to pass operational tests.
- Developtraining curricula covering press hazards, safe operating procedures, preparation, and maintenance. Training should target responsible personnel, die setters, operators, and maintenance staff, ensuring they are well-versed in the safety manual.
- Assign specific personnel toprepare written operating procedures for die assembly, press trial runs, stamping operations, daily inspections, and maintenance tasks. Training should be based on these instructions, and designated workers must be confirmed to have mastered the company’s recommended operating, preparation, and maintenance procedures.
- Conductat least one inspection of the press per week, ensuring necessary maintenance and repairs are completed before the machine is operated.
- Usedies and operating methods specifically designed to minimize risks to workers.
- Ensure all employees understand and strictly follow the rule that if any abnormal condition occurs with the press, operations must be stopped immediately. The machine must not be used again until the issue has been resolved.
- Maintain a thorough understanding of the machine’s structure, handling and installation procedures, operating methods, maintenance requirements, safety and hygiene practices, and other important precautions.
- Managers must fulfill their legal and regulatory obligations in accordance with relevant laws and regulations.
Basic Responsibilities of Designated Responsible Personnel
- Properly keep and manage the keys and switches of the press machine and its safety devices.
- If any abnormal condition is found in the press or its safety devices, immediately stop using the press, report to management, and take corrective measures such as repair.
- Strictly carry out pre-start inspections, daily inspections, and periodic checks of the press guardrails and safety devices.
Basic Responsibilities of Operators and Die Setters
- Must receive education and training on safe operation of power presses.
- Be in good physical health and free of mental conditions; ensure sufficient rest and maintain a sound mental state.
- Work calmly and steadily, maintaining a safe working posture.
- Frequently check safety devices and protective equipment; perform maintenance or repair promptly when defects are found.
- Follow work standards, stay focused on tasks, and avoid disturbing others during work.
- Take care of tools properly; never place them on the machine or the die.
- Strictly comply with work standards and carry out operations according to established procedures.
Basic Responsibilities of Maintenance Personnel
- Have a thorough understanding of the machine’s structure.
- Possess basic knowledge of mechanical maintenance and servicing.
- Be proficient in specialized maintenance knowledge of power presses.
- Regularly inspect the safety devices of the press.
Mechanical Power Press Machine Safety Guidelines – Example of the JH21 Series Press
Different models of power presses have structural and operational differences, which means the required safety measures may also vary. The following section uses the World JH21 Series C-Frame Mechanical Power Press as an example to introduce more targeted safety precautions.
Safety Devices
1. Two-Hand Operation Buttons
The two-hand control system requires the operator to press both left and right buttons simultaneously to activate the slide. During the slide’s motion, if either hand is removed from the button, the slide immediately stops. The buttons are installed at a safe distance from the point of operation.
- For single-stroke operation: When using two-hand control, if both buttons are released within the crankshaft’s 135° rotation range, the crankshaft stops immediately. However, due to the brake angle, the slide may stop slightly before or after the bottom dead center. Restarting is not possible until the machine is switched toinchorreversemode, preventing the operator’s hands from entering the danger zone. The electrical system also ensures that a single stroke cannot accidentally become continuous.
- For continuous operation: Both buttons must be pressed simultaneously for more than 3 seconds to confirm the continuous stroke mode and prevent unexpected activation. The time difference between pressing the two buttons must be less than 0.2 seconds.
⚠Warnings:
- The installation of the two-hand buttons has been designed to maintain a safe distance from the point of operation. Do not alter the installation position without authorization.
- The upper die’s front-to-back dimension must always be smaller than the slide’s front-to-back dimension. If part of the operator’s body enters the danger zone, serious injury may occur.
- When multiple operators work together, each person must use the two-hand control buttons simultaneously. Misuse could result in serious accidents.
2. Photoelectric Safety Device (Optional)
The photoelectric safety device detects when the light beam is interrupted and sends an emergency stop signal to the press. For operator safety, this device is mandatory when using foot pedal operation.
- Once powered on, the light curtain can also be set to activate during the slide’s downward stroke (this function requires assistance from the company’s service department).
- If the light beam is interrupted, the slide stops immediately (though the stopping point will lag slightly due to the brake angle).
- This safety function is available in bothsingle strokeandcontinuous stroke modes but is not active during inch
⚠Warnings:
- The upper die’s front-to-back dimension must always be smaller than the slide’s dimension. If the operator’s body enters the danger zone, accidents may occur.
- Before starting work, always confirm the device’s proper functioning according to its instruction manual.
- If any abnormal condition is found, stop operating the press immediately and perform repairs. Ignoring this rule may result in serious injury.
3. Second Drop Prevention Device
The “second drop device” is an overstroke detection and anti-repeat stroke mechanism. Users must inspect it regularly.
- For single-stroke operation, this device is essential in preventing accidental repeat strokes.
- Regular inspection and maintenance of this mechanism are critical to ensuring reliable and safe operation of the press.
Guard Device (Optional)
When closed, the guard prevents the operator’s hands or body from entering the working area. Except for manual and inch operations, if the limit switch of the guard does not detect that the guard is closed and interlocked, the slide cannot be activated.
- For presses with a table width smaller than 1300 mm, single-stroke operation with two-hand buttons is still possible even when the guard is open.
⚠Warnings:
- If the guard’s limit switch is set in an invalid position, operating the press is strictly prohibited. Without guard protection, serious injury accidents may occur.
- If the acrylic (plexiglass) or protective mesh on the guard develops cracks or damage, it must be replaced immediately.
Other Auxiliary Devices
Although the following devices are not classified as safety devices, they can prevent misoperation. Always understand their functions and use them correctly.
- Operation Power Switch
This switch cuts off the main power supply. When placed in the OFF position and the key is removed, both the slide and main motor circuits are disconnected.
- Internal Circuit Breaker
Located inside the electrical cabinet, placing the breaker in the OFF position cuts off power to the press.
Always switch it OFF before opening the electrical cabinet door to prevent hazardous operations.
- Safety Block (Optional)
During machine maintenance, always place this block between the slide and the worktable to ensure the safety of both maintenance personnel and the press itself.
Fundamental Safety Rules
- Do not modify or dismantle the machine or its control circuits without authorization. In particular, it is strictly prohibited to alter, remove, or reposition any safety-related components. Such actions may disable the safety devices, leading to serious personal injury.
- Do not operate the press outside of its specified capacity range. The machine must not be used under abnormal conditions such as tilting, overheating, or other non-standard applications. Otherwise, the safety devices may fail to function properly, causing accidents.
- Operators must not wear loose clothing or accessories. Loose garments, jewelry, or similar items can be caught in moving parts, leading to severe injuries. Depending on the task, operators should wear appropriate protective gear such as safety helmets, safety glasses, protective footwear, masks, and gloves.
- Only trained personnel should operate or maintain the press. Individuals without safety training or knowledge of the press’s hazards must never be allowed to operate it. Improper handling greatly increases the risk of accidents.
- Follow the user manual for installation, operation, and maintenance. Careless operation or performing tasks outside the scope of the manual can result in serious injury.
- Die design, production, and usage are the responsibility of the user. Users must anticipate the risks associated with the die and stamping process and adopt necessary protective measures.
- The upper die’s front-to-back dimension must be smaller than that of the slide. Failure to follow this rule will compromise the effectiveness of the safety devices, potentially resulting in injury.
Safety Rules During Installation
⚠ Incorrect operation or inspection during installation can injure workers or damage the machine.
Handling, Lifting, and Installation
- The transport, lifting, and installation of the press must be carried out by qualified technical personnel, or by an authorized transport or lifting company.
- If performed by untrained individuals, the press may tip over or cause accidents resulting in serious injury.
- Use the lifting holes located on both upper sides of the machine body for hoisting.
- Always use steel ropes and hooks capable of bearing the full weight of the press.Do not use a 90° rope angle method when hoisting.
- Exercise extreme caution during handling to avoid damaging pipelines (lubrication and air pipes), balance cylinders, or pneumatic cylinders.
- When transporting the machine in a horizontal position, drain oil from the gearbox, slide ball head, and lubrication pump to prevent oil leakage (note: oil is typically drained before shipping).
- Before moving, place rollers beneath the base to facilitate safe transport.
Electrical Connection
- Grounding and power connections must be performed in accordance with electrical equipment technical standards by qualified electricians.
- If unqualified personnel attempt electrical work, the risk of electric shock and fatal accidents is extremely high.
Environmental Conditions
- The facility where the press is installed must provide sufficient lighting and spaciousness to ensure safe and proper operation.
- The workshop temperature should be maintained within the range of 5–40°C.
Below 5°C: Oil supply may become insufficient (leading to poor lubrication).
The main motor may fail to start.
The reliability of the clutch and brake may decrease.
Above 40°C: Shaft bearings and bushings may seize.
The reliability of the clutch and brake may decrease.
Safety Rules During Operation
⚠Warning: The clutch must never be engaged when the press is under load or about to take a load. If the clutch has already been engaged, the slide must be returned to the set position by reversing the main motor. Even when working within the load curve (torque capacity) specified in the stroke-pressure diagram, if the press is stopped mid-operation and then restarted, the clutch will slip, generating excessive heat. This can cause the clutch plates to seize or misalign, creating an extremely dangerous situation that may lead to serious injury.
- Read the manual thoroughly before operating this machine. Perform all pre-start checks and daily inspections. If any abnormalities are found, repair them immediately. Operating with defects may result in accidents.
- Confirm the required tonnage for the stamping operation before installing a die. Ensure the press capacity matches the requirement.
- Do not insert hands or any body part between the upper and lower dies while the main motor is running or the slide is being adjusted. Severe crushing injuries may result.
- Never enter the press interior while the slide is in motion. Approaching the work point during operation can cause fatal accidents.
- For presses equipped with photoelectric safety devices: Do not operate the machine when the safety device is disabled.
- If the light beam is interrupted while disabled, the slide will continue moving, which can cause serious accidents.
- Always confirm the device is active and operating properly. Keep the switch keys of the press and safety devices securely controlled.
- Install protective guards around the press and in front of operators to prevent injury from flying metal fragments or chips that may scatter during operation.
- Keep the area around the press clear of unnecessary personnel and obstructions before starting work. Never place tools or objects on the worktable surface, as these can cause unexpected accidents or flying debris.
- Operate with a two-hand control system for manual operations.
- If a foot switch must be used, it must be combined with a functioning photoelectric safety device.
- Two-hand operation requires simultaneous pressing of both buttons.
- Using tools or objects to press with one hand allows the operator’s other hand or body to reach the danger zone, which can lead to injury.
- In multi-operator situations, ensure every operator is in a safe position before the press cycles.
- Do not use “inching mode” (jogging) for production.
- Inching is only for die changing or inspection.
- During inching, safety devices such as photoelectric sensors and guards may be inactive, creating accident risks.
- Do not exceed the allowable number of strokes per minute.
- Excessive speed reduces clutch/brake performance and can result in accidents.
- When adjusting slide stroke height, remain within the allowable adjustment range to avoid damaging the balancer.
- Do not adjust slide die height during stamping operations.
- If a fault occurs during slide motion, press the emergency stop button immediately. Troubleshooting must be carried out under the instructions of the responsible supervisor.
- Before mounting or removing a die:
- Turn off the main power switch.
- Release compressed air from auxiliary pneumatic devices.
- Ensure the slide is secured and will not move before beginning work.
- Never install or repair dies while the main motor or flywheel is rotating.
- When stopping work:
- Switch the main motor control to OFF.
- Disconnect power supply.
- Even when the motor is OFF, the flywheel may still rotate, allowing the slide to move.
- During this time, never place hands or body between the dies.
- If the stopping angle of the machine exceeds 30°, stop using the press immediately. Adjust and repair the machine before resuming work.
Maintenance Safety Rules
- Perform regular inspections of the press and its safety devices. Improper or neglected maintenance can result in serious accidents.
- Electrical adjustments and maintenance must be carried out only by qualified electricians. Unqualified handling may lead to misoperation, electric shock, or severe accidents.
- Before opening the electrical control cabinet, disconnect the plant power supply. Failure to do so may result in electric shock or fatal accidents.
- Replace safety components before their service life expires, even if they appear functional.
- Faulty parts must never be reused.
- Replace with original parts of the same manufacturer and model (e.g., operating buttons, emergency stop switches, clutch/brake solenoid valves).
- The dual safety valve must be inspected at the start of every shift.
- Using non-genuine parts may cause machine failure or serious injury.
- During maintenance, lubrication, or cleaning, follow all prescribed safety precautions to avoid hazardous operation.
- Remove the die from the press before performing maintenance work on the die. Failure to do so poses a risk of accidents.
- For work at heights above 1.5 meters:
- Use ladders or platforms designed for safe elevated work.
- Wear a safety belt to prevent falls.
- Never use machine parts as makeshift platforms.
Warning Signs
The warning signs attached to this power press do not cover every possible hazard. They only indicate the minimum safety warnings necessary for safe operation. Please ensure you fully understand the contents of these warnings and follow them strictly.
Warning Sign Location Diagram
The warning signs contain important safety instructions designed to prevent personal injury. The following rules must be observed:
- Strictly comply with the warning contents.
- Do not damage or deface the warning signs.
- Do not remove the warning signs without authorization.
If a sign becomes damaged, illegible, or falls off and is lost, please contact the World Group service department immediately for replacement.
Since production specifications may vary, the exact placement of warning signs may differ slightly depending on the machine model. Please always verify the warning labels on your specific equipment. Below are some examples of common warning signs:
1. “Do Not Reach In” Warning Sign
This label indicates that inserting hands into the machine may cause severe or fatal accidents.
2. “Lubrication Required” Sign
This sign instructs operators to apply lubricating oil according to the lubrication chart of the power press.
3. “Electrical Shock Hazard” Warning Sign
Before opening the electrical cabinet, the main power supply must be cut off. Failure to do so may result in accidental contact with live components, leading to serious or fatal electric shock accidents.
4. “Rotating Flywheel Hazard” Warning Sign
This sign warns that contact with a rotating flywheel can cause severe injury or fatal accidents.
Conclusion
When using a mechanical press, we must maintain a rigorous and careful approach to safety, prioritizing personal safety. If you have purchased a World brand press and require safety guidance, welcome to contact us for support.
