JH21 Pneumatic Press Manual (PDF)

This is a complete JH21 power press service manual that will guide you on how to install and operate the press correctly.

Keep reading.

Summary

1. Working principle and application of punching machine
2. Environment and Working Conditions

II Specification

III. Preparation before the operation

1. Construction and adjustment of main units
2. Frame
3. Driving Parts
4. CIutch and Brake
5. SIide
6. Hydraulic overload protector
7. Pneumatic system
8. Lubrication

VII. foundation plan

VIII. Installation and testing

1. Punch press installation
2. Moto Installation
3. Horizontal adjustment
4. Air piping installation
5. Test
6. Operation Preparation
7. Race preparation
8. Operation Preparation
9. Starting and stopping the main engine
10. Daily check-up
11. Maintenance and Security

XII. Problems and solutions

XIII. Easy-to-use parts list

XIV. Attached figures

• Figure 1 Product Structure
• Figure 2 Chart
• Figure 3 Drive Parts
• Figure 4 CIutch and Brake
• Figure 5 SIide
• Figure 6 Pneumatic schematic diagram
• Figure 7 Lubrication schematic diagram
• Figure 8 Foundation plan
• Figure 9 Front Main Shaft Bushing
• Figure 10 Main Shaft Rear Bushing
• Figure 11 Lower connection bushing
• Figure 12 Upper connection bushing

This manual is aimed at the main performance characteristic, operation warning. The figures are for reference only. The products are based on real presses.

I. Summary

Working principle and application

The JH21-80Ton (800kN) Open Back Fixed Base Punching Machine operates using a longitudinal crankshaft and crankshaft rod mechanism. The crankshaft rotates through the engine's two-stage speed reduction, which drives the reciprocating movement of the slide.

The press has a closed drive system and stable operation using a pneumatic clutch and brake, allowing the slide to stop in any position.

This universal press is ideal for sheet punching and pressing, including cutting, punching, embossing, bending, drawing and stretching, but not coining. The nominal pressure of the press is 800kN, with a normal pressure stroke of 4.5mm.

The user must choose the pressing force based on the pressure curve, ensuring that the working pressure and its crank angle do not exceed the indicated range to avoid damage to the press.

Environment and Working Conditions

To ensure the normal operation of the press, minimize maintenance frequency and extend its useful life, it should not be used in environments with excessive humidity, corrosive gases, liquids or explosive gases. The air pressure must be at least 0.6 MPa and the voltage must be 380±38V with a frequency of 50±5Hz.

II. Specification

III. Preparation before the operation

To ensure proper operation of the punch press, the user must follow proper procedures and consider the following factors before operating the machine.

Rated load capacity:

The working load must be maintained within the nominal pressure limit. Overload protection prevents overloads caused by incorrect punching or plates of non-uniform thickness during the process. It is not advisable to use the press with random overload, as this can easily damage the machine. It is important to calculate the workload before starting work.

Torque Capacity:

The piercing force will change with the position of the slide. The user must follow the stroke pressure graph that shows this change.

Pasting:

Lockup may occur if the working pressure exceeds the rated torque. Additionally, the punch press will become stuck if the load is applied before the clutch is engaged. This can damage the clutch, so if this occurs during processing, the punch press must be stopped immediately and measures must be taken to prevent this from happening again.

Eccentric load:

As a general principle, eccentric loads should be avoided as they can cause the bottom surface of the slide and butt to become non-parallel and result in unequal forces at the tip of the slide, affecting accuracy. If an eccentric load cannot be avoided, this should be done in accordance with the figure of the allowable distance that the load center deviates from the support to ensure accuracy and safety.

Single activation frequency

To ensure best performance and extend clutch and brake life, it is important to follow the recommended single activation time listed in the punch press' main specifications. Exceeding the single activation time may cause abnormal wear and failure of the clutch and brake. The recommended single activation time for this printer is no more than 25 times per minute.

4. Construction and adjustment of main units

Frame (Figure 2)

The structure of the punch press is made of high-strength steel and welded. The slide moves back and forth within the spikes. The screw on the right side of the frame is used to adjust the clearance between the spikes and the slide. Adjusting the pull rod will cause the drilled parts to be pushed downward as the slide approaches top dead center. However, care must be taken to prevent the remover from touching the bottom of the slide pull rod groove to avoid accidents. Structure reinforcement is the basis for precision measurements. It must maintain a smooth and flat surface to prevent damage from tools and cutting tools.

Driving Parts (Figure 3)

The main motor drives the flywheel via a V-belt and stores energy in the flywheel, which is then transmitted to the gear shaft via a friction clutch and brake. The gear shaft drives the large gear in the oil bath, which then drives the crankshaft to move the slide up and down.

To adjust the V-belt, first loosen the four locknuts and turn the four adjustment screws equally. Apply 2 kg of force to the center of the V-belt, which will bend 10 mm to achieve proper tension. Then tighten the four locknuts. The new V-belt will stabilize after a few days of use, but additional adjustments may be necessary. The V-belt should be kept in a cool, dry place and protected from light and oil.

When replacing V-belts, first loosen the adjusting screws, remove the old belts and uninstall the clutch brackets. It is important to replace all belts with new ones. Using new and old belts will reduce the life of the belts due to different tensions. Old belts should not be mixed with new ones, and it is important to note that belts of the same nominal size may vary in length by several centimeters. Belts in the same group must be the same length.

For automatic operation, the user can connect the automatic feeder to the frame face output shaft (the output shaft is a special order and is not included in common products).

Clutch and brake (Figure 4)

This punching machine is equipped with a pneumatic friction clutch and brake, which is located inside the frame. (See the clutch manual for more information.)

Slide (Figure 5)

The slide is a critical component of the press and its precision directly affects the precision of the press.

This JH21 punch press has square hexagonal long tips that provide good precision and stability.

The connecting rod and ball head screw are components that convert rotary motion into reciprocating motion.

The lower end of the ball head screw is in contact with the ball seat, which houses the hydraulic overload protector.

In case of overload, the protector will quickly release the oil from the die hydraulic pad, send an electrical signal and make the press stop immediately, ensuring the safety of the die and press.

Once the problem is resolved and the slide returns to top dead center, the die's hydraulic pad will automatically rebuild pressure, allowing the punch press to resume operation.

Users can adjust the height of the matrix. For instructions, refer to the relevant electrical operations in the service manual.

There are shims on the connecting rod and cover. Over time, the clearance between the crankshaft and bushings may increase.

Users can remove shims to adjust the clearance between the crankshaft and bushings. (Normal gap: 0.08-0.13mm)

4.1 Clearance Adjustment between Slide and Gibs

The distance between the slide and the tips must be appropriate to ensure smooth and reliable slide operation. If necessary, follow the steps below to adjust it correctly:

(1) Loosen the screws at the ends and the fixing screws on the right side of the structure.

(2) Adjust the left side ends and tighten the screw.

(3) Adjust the right side ends and determine whether to add or remove shims based on the gap.

After adjustment, tighten the front screws and the fixing screws on the right side.

(4) The gap between the slide and the tips should be 0.03 to 0.05 mm, but the total allowable value of the gap of the front and rear contact surface should be 0.04 to 0.08 mm.

Normally, the gap between the upper and lower ends is greater. The measurement is accurate when the depth of the thickness gauge is greater than 30mm.

Note: The 0.03mm gauge must be inserted, the 0.05mm gauge must not be inserted.

(5) After adjustment, check the clearance of each part and adjust again if necessary.

4.2 Slide extraction device

The knockout force is 5% of the nominal pressure.

4.2.1 Structure of Slide Disassembly Equipment

(1) It consists of the extraction rod, extraction seat and extraction bar.

(2) The elimination bar is located above the center line of the slide, across the slide.

(3) When the slide rises, the extraction bar touches the extraction rod, ejecting the drilled parts.

4.2.2 Operation and Adjustment of Slide Extraction Equipment

(1) Unscrew the extraction rod fixing screw and adjust the extraction rod to the appropriate position. Note that the extraction rods on the left and right sides must be at the same height.

(2) After adjustment, tighten the fixing screws.

(3) Touching the cross bar and slide may cause noise when using the cross bar.

4.2.3 Warning

When changing the die, be sure to raise the pull rod to its highest position before adjusting the slide height to avoid hitting the pull rod while adjusting the die height.

Adjust the position of the draw bar so that material is pushed in when the slide moves near top dead center.

However, do not let the opening bar touch the bottom of the opening groove to avoid accidents.

4.3 Counter

The counter, installed on the electrical panel, is used to monitor and display the accumulated number of strokes.

The counter will record a count of 1 each time the slide moves up and down.

If a reset is required, press the reset button.

The counter can be used to calculate production.

4.3.1 Counter Panel

4.3.2 Operational Method

(1) Set the switch to OFF position and the counter will not work.

(2) Turn the switch to ON and the counter will work.

Observation:

When resetting the counter, the slide must be stopped at top dead center. If the counter is reset while the punch press is still in operation, it may damage the counter.

Hydraulic overload protector

The hydraulic overload protector can automatically detect the oil pressure of the slide oil hydraulic cylinder. If the pressure is insufficient, it can quickly supply pressure to maintain normal operation. In case of overload caused by incorrect drilling or uneven sheet thickness during the process, the protector can immediately discharge to protect the accessories and die from damage. The hydraulic overload protector consists of a pressurized cylinder, a pressure relief valve and an inductive switch.

5.1 Preparation before operation of the Hydraulic Overload Protector

• Check the oil level and make sure there is enough oil in the air pump. If the oil level is low, loosen the leak port screw and add antioxidant pickling hydraulic oil (ISO VG-32) or other hydraulic oil with similar performance.

• Make sure the air gauge is normal.
• If the slide stops at top dead center, press the reset button and the pneumatic pump will start working. After about 1 minute, the oil pressure will reach the specified value and the air pump will stop.
• If the slide does not stop at top dead center, do the following:

① Set the operation mode to “INCH” stroke.

② Use the operation button to slowly advance the slide until it stops at top dead center. (Be careful with the working height of the die for safety if it has been installed)

③ As soon as the slide reaches top dead center, press the reset button and the overload protector air pump will start to work. After about 1 minute, the pressure will reach the specified value, the air pump will automatically stop, and the overload indicator light will go out.

④ The punch press can now be used in single or continuous operation modes.

⑤ Preparation for operation is completed.

(6) Air elimination of oil pressure pad in hydraulic overload protector

If there is air in the oil pressure pad, the hydraulic overload protector function may not work properly and cause the air pump to run continuously.

To eliminate air:

① Stop the slide at top dead center.

② For safety, turn off the main engine. Wait until the steering wheel comes to a complete stop. Then use a hex wrench to loosen the oil drain hole bolt on the hydraulic overload protector, allowing the oil to drain.

③ If the oil flows brokenly or with bubbles, it indicates the presence of air.

As soon as the oil stops flowing in a broken or bubbling manner, tighten the oil drain hole screw. Check the joint between the pump and the end plane of the oil box for gas leaks and make sure the oil pipes are not leaking.

④ Air purging is complete.

(7) Hydraulic Overload Protector Reset:

If the punch press is overloaded, the overload indicator will light up.

Operate it according to step (5) of the procedure.

5.2 Overload Protector Maintenance

(1) Regularly check the pipe connected to the safety valve for gas leaks.

(2) Clean the oil filter periodically.

(3) Regularly check the tightness of the screws of the connecting parts.

(4) Regularly check the oil level in the box.

(5) Periodically check the operation of the electromagnetic valve.

5.3 Common Failures and Troubleshooting of Hydraulic Overload Protector

V. Pneumatic System (Figure 6)

The solenoid valve is the main running component and has self-control function. If one valve does not work properly, the other valve will release air, causing the clutch to disengage and the slide to stop, ensuring the safety of people and the press. The air source pressure must be between 0.55 and 0.6 MPa, and it is important to adjust it to the specified value. The lubricator must maintain a certain oil level, and the gas filter and air reservoir must be frequently drained of water and contaminants.

Punch press and compressor air consumption

JH21-80 clutch air consumption: 0.18 m3/min. It is recommended to choose a 0.3 m3/min compressor for a single press.

To perceive:

(1) When adding oil to the lubricator, the air pressure in the pipeline must be released to avoid accidents.

(2) The pressure of the counterweight cylinder and the weight of the upper die can be adjusted according to the following figure. The maximum allowable working pressure of the counterweight cylinder is 0.8 MPa.

(3) The electrical relay interconnects with the electrical circuit. If the pressure is too low, the circuit will not work. The pressure relay was adjusted before being shipped from the factory; should not be adjusted randomly.

SAW. Lubrication (Figure 7)

The punching machine adopts intermittent automatic lubrication system and manual oil lubrication. Oil is pumped to all lubrication points through the oil promoter distributor. The flywheel bearing, rotary joint and air cushion are lubricated with an oil gun.

The lubrication system is crucial for the crankshaft press. Reduces wear on accessories, increases service life, ensures precision and reduces energy consumption and maintenance costs. Therefore, all relative moving parts must be lubricated, except the friction surface of the friction clutch and brake.

When operating the press, it is important to monitor the effect of lubrication to avoid blockages in the oil paths and to prevent the main bushing, connecting rod bearing and sliding pins from overheating and being damaged. The temperature must not exceed +70°C and must not be lower than -35°C. If the temperature rises, the punching machine must be stopped immediately. The main engine temperature must not exceed +60°C (measured on the engine cover).

The lubricating oil in the gearbox should be replaced for the first time after 3 months (approximately 750 hours) of use and every 6 months (approximately 1,500 hours) thereafter. The gearbox should also be cleaned every 6 months.

Flywheel bearing and driveshaft bearing lubrication is included and must be filled with grease before assembly. Lubricating grease (3# lithium grease) should be refilled once every 2 months and checked every 6 months. When putting grease into the bearing, fill 60-70% between the flywheel and the bearing.

The counterweight cylinder uses air lubrication and manual oil gun lubrication. To ensure the lubrication of the ball screw and ball seat, 100ml of 20# oil should be added before testing after installation. The lubricator should be filled with 20# oil and checked weekly.

Note: Lubrication and oil change must follow the lubrication instructions indicated on the press.

Lubrication during operation:

First start the main engine and wait 5 minutes for the lubrication pump to start working. Then, start operating the press.

When the press has been idle for 24 hours, the main engine must run for 10 minutes before starting production.

Lubricating oil reservoir:

Check the lubricating oil reservoir daily and refill as necessary.

During the initial installation period, more oil is required and must be refilled immediately.

Manual Lubrication:

Power must be turned off during manual lubrication.

Oil Replacement:

When changing the oil, it is necessary to thoroughly clean the inside of the oil reservoir and pipes.

Lubrication table:

NO.	Lubrication Point	Brand and type of lubricating oil	Lubricant Mode
1	connecting rod bushing	00# Lemon grease	Motorized lubrication
two	Front main bushing	00# Lemon grease	Motorized lubrication
3	Rear main bushing	00# Lemon grease	Motorized lubrication
4	Gib (6 points)	00# Lemon grease	Motorized lubrication
5	Connecting wire	CKC150 gear oil	Manual lubrication with oil gun
6	Ball screw	CKC150 gear oil	Fill lubrication with oil
7	Gear box	CKC150 gear oil	Immersion lubrication
8	Balancer	HL150 Lubricating Oil	Manual oil pump lubrication
9	manual oil pump	HL150 Lubricating Oil
10	grease pump	00# Lemon grease	Electric lubrication
11	Air cushion lubrication points	2# Lithium grease	Manual lubrication with oil gun
12	Steering wheel bearing	2# Lithium grease	Manual lubrication with oil gun

VII. Foundation plan (Figure 8)

Preparation before construction

1.1 Excavate according to the foundation plan.

1.2 If the soil is soft, piles must be driven to reinforce it. (Ground pressure should not be less than 8 ton/m²)

1.3 Place rubble at the bottom at a height between 100mm and 200mm.

1.4 Leave holes in the base when pouring concrete.

• Prepare the concrete according to the foundation plan.
• After the concrete has dried, remove the wooden sheet.
• When installing the punch press, mount the press, anchor bolts and horizontal adjustment plate in the well. After adjusting the punching machine horizontally, fill the anchor well with concrete.
• Let it dry and then make repairs.

(1) Customers must prepare the base around the punching machine using appropriate materials.

(2) If shock protection is required, a layer of fine sandstone about 150 mm wide should be added around the foundation.

VIII. Installation and testing

Before adjusting the press, it is important to understand its structure well.

Press installation :

Prepare the foundation according to the foundation plan. If the ground is soft, reinforce it appropriately with iron reinforcement.

Once the press arrives at the factory, place it in a dry place for several days to check the electromotor and transformer before starting the installation process.

The punch press is coated with anti-rust oil during transportation, so be sure to clean it before installation. Pay special attention to cleaning the oil from the tip surfaces and friction surfaces.

Measure the levelness of the press using a precision leveler and fix the foundation screws only when the level meets the required standard.

When adjusting the press, please note that the flatness should be 0.3/1000 mm. Confirm that the bracket is secure before measuring levelness.

If the user chooses to install the stand themselves, they must ensure that the interface between the stand and the work table is clean and free from debris such as paper, metal scraps, gauges, washers and dirt.

Engine installation

The main motor is normally installed on the punching machine. If it becomes necessary to dismantle it during transport, it must be reinstalled as follows:

• Unpack the packaging and check for damaged accessories.
• Clean the engine, belt pulley, flywheel groove and bracket. Avoid dropping liquids on the electric motor. Clean the V-belt using a cloth, not a cleaning solution.
• Mount the engine in the pivot position, but do not fully tighten the screws. Be sure to support the weight of the engine with a strap before tightening the screws.
• Align the reference line of the belt pulley groove and the flywheel groove and position the engine correctly.

Note: Avoid letting any liquid come into contact with the electric motor.

If the reference line of the belt pulley groove and flywheel groove are not aligned, it may cause damage to the belt groove and engine bearing.

After aligning the reference line, tighten the engine support screws.

Move the engine to the flywheel and make sure the V-belt does not have excessive tension as it is placed on the block.

Observation:

Do not force the belt into the groove.

After installation, the belt tension should be about 10 mm when pressed with your thumb.

Horizontal adjustment

Stand leveling is very important and most presses come with a stand. Before measuring, make sure the screws are tight. Start by cleaning the pad and placing a precision level gauge in the front, middle, and back of the pad. Shims can be used to adjust the leveling of the frame.

Observation:

① The shims must be large enough to ensure that the press foot supports the weight evenly at the interface.

② Check the leveling after one month. If an error appears, readjust the leveling. Check other items every six months and ensure the press is level to maintain its performance.

Air duct installation

The air line must be connected to the back of the press, with a required air pressure of 0.6 MPa. However, the distance from the air source to the press should not be more than 5 meters and the diameter of the piping should not be less than 1 inch. Make sure the channel is clean of dust and debris.

Test

After installation, check the accuracy according to the certificate. During transportation, jostling and vibrations can affect accuracy, so it may need to be adjusted. The punch press can only be used when the accuracy is correct. Before starting the press, clean any grease and dirt, especially the tip and friction surfaces, and select the appropriate operating procedure based on the job requirements and prepare the necessary tools. After installing the die, use an inch stroke and gradually move the slide to bottom dead center.

Special Notice:

Do not let the dies collide with each other and adjust the height of the dies manually.

After adjusting the matrices, do not start a single or continuous stroke.

Adjust the position of the pull bar to allow ejection of the part after the slide travel stops (near top dead center).

However, when the slide moves to top dead center and the draw bar is pushed down, be careful not to touch the bottom of the draw bar groove and disturb its movement.

After adjustment, use the inch stroke and advance step by step.

The single and continuous stroke can be carried out as long as nothing prevents the press from functioning properly.

The air pressure of the punch press should be between 0.55-0.60 MPa, and the maximum pressure of the safety valve should be 1 MPa.

IX. Operation Preparation

Race preparation

(1) Turn the air switch on the main control box to the ON position and make sure the punch press is working properly.

(2) Close the main control box door.

Attention: For safety reasons, it is prohibited to open the main control box door while the press is running.

Operation Preparation

(1) Turn on the switch on the operation panel and the power indicator (AC110V loop) will light up.

(2) Check that the “Emergency Stop” button is not activated.

(3) If the pressure is not within the normal range, the indicator will go out and the punch press will enter an emergency stop state.

Correct the air pressure to the appropriate value and operate the press until the indicator lights.

Start and stop the main engine

The following steps must be performed to start and stop the main engine:

• Press the start button, the main engine will start and the main engine indicator will light up.
• Note: The main engine will only run if the mode switch is in the “OFF” position.
• To stop the main engine, press the engine stop button. The main engine will stop working and the indicator will go out.

It is important to note that the main engine will automatically stop in the following scenarios:

• The circuit fuse in the main engine blows.
• The thermal relay is in protection mode.

X. Daily Check-up

Initial check:

• Clean the pillow and make sure nothing is placed on it.
• Operate the steering wheel using the lock bar.
• Make sure the power cord specifications meet the requirements.

Check after opening the air valve

• The clutch air pressure must be within the specified range of 0.55-0.6 MPa.
• Air leaks are not permitted.
• No air leaks should be present in the clutch cylinder or rotator joint.

Check after calling

• Turn the switch to ON and the power and pressure indicators should light up.
• Set the mode selection switch to the “inch travel” position. Press and release the “two-hand” operation button, check the solenoid valve action and ensure air release and flexible clutch movement without interference.

Check after starting the main engine

• Press the start button and the main engine will run and the indicator will light up.
• Check that the direction of rotation of the flywheel is the same as that marked on the press.
• Check the starting speed and acceleration of the steering wheel.
• The sound of the V-belt slipping should be normal.

Running scan

• During the inch stroke, make sure the press operates smoothly and without abnormal noises or heaviness. To do this, press and hold the two-hand operation button.
• In Single and Continuous Stroke, movement should be normal. In the continuous stroke, press the emergency stop button to ensure that the clutch separates and the emergency stop button can be locked.
• In Single Stroke, the press should not run continuously when pressing the operation button. The stopping position must be between +5° and -10° from top dead center, with no deviation permitted.
• In continuous travel, pressing the stop button should result in the stop position being between +5° and -10° from top dead center. Any deviation is not permitted.
• In Continuous Stroke, pressing the emergency stop button should result in the punch press immediately stopping.

Checking when adjusting the slide

• Turn the slide adjustment switch to ON, operation will be prohibited.
• Adjust the height of the matrix. When the slide reaches the upper and lower limits, engine adjustment must be stopped.
• Check whether the array height indicator matches the actual value.

XI. Maintenance and Security

Operate strictly in accordance with the manual and safety procedures:

The clutch must be engaged after the engine starts and runs at full speed.

Maintain good equipment grounding and check it frequently.

Turn off the power when the operator leaves the press.

The press working load must be within the safe range.

Do not operate the punch press if the safety device is not fitted.

Punching two sheets is strictly prohibited.

If the slide falls freely or hits unevenly with noise, stop the punch press immediately and inspect it.

Check the air piping frequently. If an air leak is detected, repair it before operating the punch press.

For the sake of personal safety, it is prohibited to place any part of the body in the dangerous area of ​​the die. It is also prohibited to work or carry out maintenance in the dangerous area before taking safety measures.

The photoelectric protector is optional. The press has connection points for the photoelectric protector.

XII. Problems and solutions

XIII. Easy-to-use parts list

XIV. Attached figures

Figure 1 Product Structure
Figure 2 Chart
Figure 3 Drive Parts
Figure 4 CIutch and Brake
Figure 5 SIide
Figure 6 Pneumatic schematic diagram
Figure 7 Lubrication schematic diagram
Figure 8 Foundation plan
Figure 9 Front Main Shaft Bushing
Figure 10 Main Shaft Rear Bushing
Figure 11 Lower connection bushing
Figure 12 Upper connection bushing