The Operating Procedures Of Punch Press

Punch is a very common equipment in our lives, it is also what we often call stamping press. For the punch press, it is usually divided into three parts: the punch die, the lower die and the knife wall. The die on the punch is the upper half of the entire die, which is also a die mounted on the slider of the press. The upper die seat is the uppermost plate-shaped part of the upper die. When the workpiece is close to the slider of the press, it is fixed with the slider of the press through the die handle or directly. The lower die is the lower half of the whole set of die, which is the die installed on the working table of the press. The lower mold base is the bottom plate-shaped part of the lower mold, which is directly fixed on the work surface of the press or the backing plate when working. The blade wall is the side wall of the cutting edge of the punching die hole. The slope of the cutting edge is the slope of each side of the wall of the punching die hole. The air cushion is a bomb ejector that uses compressed air as the driving force. 

The opposite side pressure block is a part that supports the one-way force-bearing punch from the other side of the working surface. In national production, the stamping process has the advantages of saving materials and energy, higher efficiency than traditional mechanical processing, low technical requirements for operators, and making products that cannot be achieved by mechanical processing through various mold applications. Its uses are becoming more and more extensive. For example, we use switch sockets, cups, cupboards, dishes, computer cases, and even missile aircraft… 

There are a lot of accessories that can be produced through molds with a punch. The following editor of Xianji.com will introduce to you the operating procedures, uses and characteristics of the punch press, common problems and solutions of the punch die, and the maintenance and repair methods of the punch.

Punch operating rules

Implement the factory safety technical code and the equipment operating procedures.

• (1) Check the stamping work area for irrelevant workpieces and debris before going to work. After cleaning, check whether the upper and lower molds and screws are loose. If the mold is loose, the mold must be reassembled.
• (2) When an abnormal problem is found, such as abnormal sound, etc. The main power supply must be turned off before troubleshooting or repair.
• (3) When closing the mold, it should be stopped when the flywheel is stopped. When the mold is closed, manually check the stroke of one to two times, and the machine can be turned on after it is correct.
• (4) Articles must be placed strictly in accordance with the requirements and not placed at will. When off work, if the upper and lower molds are in position or the mold clamping work is not completed, a warning sign is strictly prohibited. Turn off the main power supply after work and turn off the power supply box.

Before working, move the flywheel for a few revolutions by hand or turn off the electric button as soon as it is turned on. Do not start suddenly, and check the following conditions.

• (1) It is necessary to check whether the lubrication system and mechanical system of the machine tool are normal. The self-contained refueling pump is used to refill the lubricating oil once to prevent the crankshaft copper sleeve and the sleeve rail from being strained by dry wear.
• (2) It is necessary to check whether the clutch and brake are flexible and easy to use, and whether the pedals, pull rods, molded plates, screws and various transfer devices are loose.
• (3) It must be checked whether the punch can move freely on the guide rail, whether the flywheel is jumping, and whether the flywheel clutch is reliable.
• (4) It is necessary to check whether the protective cover, die and pressing plate are firmly installed, and whether the punch has repeated hits.
• (5) It is necessary to check whether the ejector is operated accurately and whether the blank material is suitable for stamping.
• (6) It is necessary to check whether the electrical grounding wire is intact and reliable.

What is the operating procedure of punching machine? What are the uses and characteristics?

Disengage the live pin clutch before driving, and disengage the coupling when stopping, before starting or stopping the motor transfer.

Fourth, the following points must be paid attention to when installing the die:

• (1) The contact points of the upper and lower dies must be wiped clean. The guide shaft sleeve of the die must not be exposed to the guide shaft. They should be connected together, and the punch must be installed.
• (2) The upper and lower die must be parallel, the upper punch and the lower die surface must be perpendicular, the die pressing plate must be flat, and the pressing plate screws must be tightened in a symmetrical direction.
• (3) The punching force center of the punch must coincide with the pressure center of the punch, and the maximum punching force shall not exceed the rated pressure of the machine.
• (4) It is not allowed to take screws and other objects under the die and pallet by hand to prevent crushing the hand.
• (5) When loading and unloading the die, lubricating the machine tool and troubleshooting faults, the power supply must be cut off, and the flywheel can stop rotating before proceeding.
• (6) After the mold of the punch below 100T is installed, transfer it by hand to proofread it and test it with a paper sheet. It is not allowed to watch near the cutting edge during the test.

The following items must be implemented during the stamping process

• (1) It is forbidden to revise the blank position of the die during the operation of the slider and after the pedal or handle has been stepped on.
• (2) It is forbidden to work when the operating mechanism and the automatic shutdown mechanism are not operating normally.
• (3) It is forbidden to put anything on the punch table and change the pedal mechanism or pad any objects.
• (4) It is forbidden to put more than one blank on the die at the same time and clean the iron filings and edge material by hand.
• (5) It is forbidden to work when the impact of the punch and the abnormal sound of the automatic falling are found.
• (6) The mold condition should be checked frequently, and rigid objects higher than the height of the closed mold should not be placed in the stamping area.
• (7) It is forbidden to forcibly punch two or more pieces of the workpiece, and only one piece is allowed to be punched at a time, so as to avoid equipment, molds, damage and personal accidents.
• (8) It is forbidden to clean the ash and slag by hand, put in parts, and use cameras and tools when picking up the workpiece.
• (9) It is forbidden to put your hands or head between the punches, dies, and pads.
• (10) It is forbidden to clean, refuel or go to the top of the equipment to observe the operation and repair during operation.

Punch uses and characteristics

Punches are widely used in stamping and forming of electronics, communications, computers, household appliances, furniture, vehicles, (automobiles, motorcycles, bicycles) hardware parts, etc.

• 1. The high-rigidity, high-precision frame is welded by steel plate, and after heat treatment, the internal stress of the fuselage technetium is eliminated so that the equipment can work stably for a long time without deformation. The structural parts have uniform load and balanced rigidity.
• 2, stable high precision:The main parts of the equipment, such as the crankshaft, gears, transmission shaft, etc., are hardened and heat-treated, and have high wear resistance after grinding. The long-term performance is stable and the requirements for high precision and stability are ensured.
• 3, reliable and safe operation performance:The reason for the convenient operation and accurate positioning is that different from the traditional brake, the clutch/brake combination device has high sensitivity, plus the double solenoid control valve and overload protection device commonly used in international high-end equipment. Ensure the accuracy and safety of the high-speed movement and stop of the punch slide.
• 4. Production automation, labor-saving and high efficiency.The punch can be equipped with corresponding automatic feeding device, with feeding error detection, pre-cutting, and pre-cutting devices, which can fully realize automatic production, with low cost and high efficiency.
• 5. Slider adjustment mechanism:Sliding fast adjustment is divided into manual adjustment and electric adjustment, which is convenient, reliable, safe and fast, and the accuracy can reach 0, 1mm.
• 6. Novel design and environmental protection.Adopting advanced technology and design concepts from Japan and Taiwan, it has the advantages of low noise, low energy consumption and no pollution.

Common problems and solutions for punch molds

The punch wears out too fast

The main reason:

• ①The mold gap is too small.
• ②Poor alignment of the convex-concave mold, including the lack of precision of the mold base, mold guide components, and turret inserts, etc., resulting in poor mold alignment.
• ③The temperature of the punch is too high, mainly due to the overheating of the punch caused by the same mold for a long time.
• ④Improper mold sharpening method, resulting in increased mold annealing wear.
• ⑤Partial unilateral punching, such as nibbling, angle of attack or shearing, the lateral force will make the punch to one side, the gap on this side will be reduced, causing serious mold wear. If the machine tool mold installation accuracy is not high, serious This will cause the punch to deviate from the lower die, causing damage to the punch and die.

Mold with material problem

(1) Mold strips will cause scrap to rebound. The related factors:

• ①The sharpness of the cutting edge of the mold, the larger the rounded corner of the cutting edge, the more likely it is to cause the scrap to rebound.
• ②The modulus of the mold, the modulus of each station of the machine tool is fixed, and the small modulus of the mold will easily cause the scrap to rebound.
• ③Whether the mold gap is reasonable, if the mold gap is not suitable, it is easy to cause the scrap to rebound.
• ④ Whether there are more oils on the surface of the processed plate.
• ⑤The spring is damaged due to fatigue.

(2) Methods to prevent mold stripping:

• ①Use a special anti-banding die.
• ②The mold is often sharpened to keep it sharp and demagnetized.
• ③Increase the die gap.
• ④The oblique blade mold is used instead of the flat blade mold.
• ⑤The mold is equipped with an ejector.
• ⑥ Reasonably increase the modulus of the mold.
• ⑦Check the fatigue strength of the mold spring or discharge sleeve.

Mold alignment problem

(1) Die is prone to have different wear on each side of the punch during use, and some parts have larger scratches and wear faster. This situation is particularly obvious on narrow rectangular molds. The main reason for the problem:

• ①The machine tool turret design or machining accuracy is insufficient, mainly due to the poor alignment of the mold mounting seat of the upper and lower turntables.
• ②The design or machining accuracy of the mold cannot meet the requirements.
• ③The accuracy of the guide bush of the mold punch is not enough.
• ④The mold gap selection is inappropriate.
• ⑤The mold mounting seat or mold guide sleeve is not neutral due to long-term wear and tear.

(2) To prevent inconsistent mold wear:

• ①The centering mandrel is regularly used to check and adjust the neutrality of the machine tool turret and mounting seat.
• ②Replace the mold guide sleeve in time and choose a convex-concave mold with appropriate clearance.
• ③Using a full-lead mold.
• ④ Strengthen the sense of responsibility of the operators, and find out the cause in time to avoid greater losses.

The use of special forming molds

(1) In order to meet the production needs, forming molds or special molds are often used, mainly including bridge molds, shutter molds, counterbore molds, hole tapping molds, boss molds, stretch molds, combined molds, etc. The use of special or forming molds can greatly improve production efficiency.

(2) In order to avoid mistakes, the following principles should be observed and followed:

• ①When installing the mold, check the direction to ensure that the installation direction of the mold male and female molds is the same.
• ②According to the requirements, adjust the punching depth of the mold correctly.
• ③Use a lower punching speed.
• ④The plate should be flat without deformation or warping.
• ⑤The forming processing position should be as far away from the clamp as possible.
• ⑥ When using forming dies, avoid downward forming operations.
• ⑦When punching, press the ordinary mold first, and use the forming mold last.

The selection of stamping oil

In the production of metal stamping and drawing, the factors that affect the yield of stamping and drawing are roughly the accuracy of the stamping equipment, the rationality of the mold design, the quality of the stamping die, and the performance of the stamping oil.

• ①Silicone steel plate is a material that is relatively easy to punch. Generally, low-viscosity punching oil is used to prevent punching burrs for the ease of cleaning of the finished product.
• ②When selecting stamping oil for carbon steel plates, the first thing you should pay attention to is the viscosity of the drawing oil. The best viscosity is determined according to the difficulty of processing, the method of drawing the oil and the degreasing conditions.
• ③ Stainless steel generally uses stamping oil containing sulfur and chlorine compound additives to ensure extreme pressure processing performance while avoiding problems such as burrs and cracks on the workpiece.

Punch maintenance and repair methods

Before work starts

• 1. Punch workers must learn, master the structure and performance of the equipment, be familiar with the operating procedures and obtain operating permits before they can operate independently.
• 2. Check for oil and gas leakage. Is the amount of fuel in the fuel tank sufficient? Check whether the air pressure is normal and whether there is drainage in the air tank.
• 3. Check whether the lubrication of each transmission, connection, punch friction part and other parts of the machine tool and the protective safety device are normal, and enough lubricating oil should be added to the hand-operated oil pump.
• 4. Check that the mold press block is firmly and reliably fixed on the machine table, the upper and lower molds are aligned to ensure that the position is correct, the blanking hole cannot be blocked, and whether there are cracks, dents or collapses in the upper and lower mold cavities. Confirm that the motor is stopped, use the special climbing rod for this punch to test punch, and ensure that the mold is working in good condition.
• 5. Use the safety protection and control devices on the equipment correctly, and do not dismantle them arbitrarily.
• 6. Remove all floating objects on the bed. The motor can only be started when the clutch is disengaged.
• 7. The machine tool should be idling for 2-3 minutes before working. Check the flexibility of the foot brake and other control devices, and then use it after confirming that it is normal. It should not run with illness.
• 8. Before working, you must wear work clothes and protective gloves; female workers must wear work caps, and hair braids must not be exposed outside the work cap; slippers are prohibited.
• 9. Workers are prohibited from drinking alcohol within eight hours before work. Ensure a good mental state.

During working hours

• 1. Press the oil pump to deliver the lubricating oil regularly by hand
• 2. It is absolutely forbidden to load two or more sheets at the same time.
• 3. If the workpiece gets stuck on the die, stop the punch and conduct research and treatment in time.
• 4. When working, the flash on the workbench should be removed in time, and pliers or brushes should be used when removing.
• 5. When doing shallow stretching work, pay attention to the material clean and lubricate. 6. When single punching, the hands and feet are not allowed to be placed on the hand and foot brakes, and must be lifted (stepped) at a time to prevent accidents.
• 7. Do not change the position of the blank on the die by hand.
• 8. When two or more people operate together, the person responsible for moving (stepping on) the gate must pay attention to the actions of the feeder. It is strictly forbidden to pick up the parts while moving (step on) the gate.
• 9. If there is abnormal noise or other abnormal phenomena during the stamping work, press the emergency stop switch to stop the work and disconnect the main power switch. Report to study and deal with repairs.
• 10. When the punch is started or is running, the operator must stand properly, keep a certain distance between his hands and head and the punch, and always pay attention to the movement of the punch, and it is strictly forbidden to chat with others.
• 11. It is forbidden to reach directly between the upper and lower molds to feed or take parts by hand.
• 12. When punching long parts, safety racks should be set or other safety measures should be taken to avoid digging injuries.
• 13. Stop in time at the end of the work, cut off the power supply, and close the air valve.

After the work is completed, the equipment should be maintained at the first level

• 1. Cleaning and cleaning equipment.
• 2. Lubricate the rail crankshaft and connecting rod screw ball head shaft.
• 3. Check whether the manipulator, clutch and brake are normal.
• 4. Check whether the oil circuit and oil pump are in good condition.
• 5. The punching table, guide rails, molds, etc. shall be protected against rust during holidays.

Second level maintenance content

• 1. Regularly check the operation of the drive shaft, copper sleeve and bearing for 3 months, disassemble and refuel or replace.
• 2. Check the manipulator clutch, disassemble and refuel, observe its wear and tear, repair or replace it.

Level 5 and Level 3 Maintenance According to the equipment’s operating conditions, the key parts of the equipment should be inspected once during the two-year three-guarantee disassembly, in order to restore the performance and accuracy of the equipment.

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