Estimated reading time: 9 minutes
We often hear others talk about punching machines, but many people still don’t know what punch presses are. In fact, the punch is a stamping press. Nowadays, punch presses are very popular among many industries. Compared with traditional processing machinery, punch presses have the characteristics of saving materials and high production efficiency. At the same time, punch presses do not require high user operations, so they can be widely used in electronics and communications. Computers, household appliances, furniture, transportation (automobiles, motorcycles, bicycles) hardware parts, and other stamping and forming. Moreover, the common switch sockets, cups, cupboards, dishes, etc. around us can also be produced through molds with a punch press. Isn’t it amazing?
Through today’s article, everyone will learn about the relevant knowledge of the punch press, including punch press specifications, types, working principles, characteristics, operation precautions, maintenance, and so on.
Punch Press Specifications
Generally speaking, the specifications of punch presses often used by manufacturers are as follows: 10T, 16T, 25T, 40T, 63T, 80T, 100T, 125T, 160T, 200T, 250T, etc. Unless it is processing very small or very large products, 6.3T, 315T, 400T, 500T models of punch presses will be used.
Types of Punch Press
Classification according to the driving force of the slider
Punch presses can be divided into two types: mechanical type and hydraulic one.
In general sheet metal stamping processing, most use mechanical punching machines. According to the different liquids used in hydraulic presses, there are hydraulic presses and hydraulic presses. At present, most hydraulic presses are used, while hydraulic presses are mostly used for large-scale machinery or special machinery.
Classification according to the movement of the slider
According to the movement of the slider, there are single-acting, double-acting, and three-acting punching machines. At present, single-action punching machines are the most commonly used in the processing industry. Double-action and three-action ones are mainly used in the extension processing of automobile bodies and large-scale processed parts, which are relatively small processing applications.
Classification according to the slider drive mechanism
- Crankshaft type
A punching machine using a crankshaft mechanism is called a crankshaft punching machine, and most of the current mechanical punching machines are of this kind of mechanism. The crankshaft mechanism has many advantages, such as easy production, the ability to accurately determine the lower end position of the stroke, and the slider movement curve is generally suitable for various processing. Therefore, this type of stamping is suitable for almost all punching processes such as punching, bending, stretching, hot forging, warm forging, and cold forging.
- No-crankshaft type
The no-crankshaft punching machine is also called the eccentric gear punching machine. Compared with the eccentric gear punching machine, the eccentric gear punching machine structure is superior to the crankshaft structure in terms of shaft rigidity, lubrication, appearance, and maintenance. The disadvantage is that its price is higher. When the stroke is longer, the eccentric gear punching machine is more advantageous; when the stroke is shorter, the crankshaft punching machine is more advantageous. Therefore, small machines and high-speed presses are also the fields of crankshaft power presses.
- Toggle type
A punching machine that uses a toggle mechanism on the slider drive is called a toggle punching machine. This type of power press has a slider speed near the bottom dead center that will become very slow (compared to a crankshaft punching machine), so it also correctly determines the bottom dead center position in the stroke. Therefore, this type of punch is suitable for compression processing such as stamping, processing, and finishing, and cold forging is now the most used.
- Friction type
A punching machine that uses friction transmission and a screw mechanism on the track drive is called a friction punching machine. This type of punching machine is most suitable for forging, and can also be used in processing processes such as bending, forming, and stretching. It has diverse functions and was widely used before the war because of its low price. Due to the inability to determine the lower end position of the stroke, poor processing accuracy, slow production speed, overload when the control operation is wrong, and the need for skilled technology in use, it is gradually being eliminated.
- Spiral type
A punching machine using a screw mechanism on the slider drive mechanism is called a screw punching machine.
- Rack type
A punching machine that uses a rack and pinion mechanism on the slider drive mechanism is called a rack punching machine. Spiral punching machines and rack punching machines have almost the same characteristics, and their characteristics are roughly the same as those of hydraulic punches. It used to be used for pressing into bushings, crumbs, and other items, such as squeezing, oil extraction, bundling, and ejection of bullet casings (hot-room squeezing processing), but now it has been replaced by hydraulic presses unless extremely special No longer used outside of the situation.
- Connecting rod type
A punching machine that uses various linkage mechanisms on the slider drive mechanism is called a linkage punching machine. Using a connecting rod punching machine, while keeping the drawing speed within the limit during deep drawing, shortening the processing cycle and improving production efficiency. This type of power press is generally used for deep drawing of cylindrical containers with a narrow bed surface, but recently it has been used for the processing of automobile body panels with a wider bed surface.
- Cam type
A punching machine that uses a cam mechanism on the slider drive mechanism is called a cam punching machine. The feature of this type of punch is to make an appropriate cam shape, but because of the nature of the cam mechanism, it is difficult to convey a large force, so the capacity of this type of punch is very small.
The Working Principle of The Punching Machine
The design principle of the punch press is to convert circular motion into linear motion. The main motor generates power to drive the flywheel, and the clutch drives the gear, crankshaft (or eccentric gear), connecting rod, etc., to achieve the linear motion of the slider. The punch presses the material to deform it to obtain the required shape and precision. Therefore, it must be matched with a set of molds (upper mold and lower mold), the material is placed in between, and the machine applies pressure to deform it, Processed into the designed workpiece.
- High rigidity
The fuselage is a high-precision frame, welded by steel plates, and heat-treated to eliminate the internal stress of the fuselage, ensuring long-term stable operation of the equipment without deformation.
- Stable high precision
The main parts of the equipment, such as 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.
- Reliable and safe operation performance
The reason why the punching machine is easy to operate and accurate in positioning is because it uses a brake that is different from the traditional one. The clutch/brake combination device has high sensitivity, coupled with the double solenoid control valve and overload protection device commonly used in international high-end equipment, to ensure the accuracy and safety of the high-speed movement and stop of the punch slide.
- Production automation, labor saving and high efficiency
The punching machine can be equipped with a corresponding automatic feeding device, with feeding error detection, and pre-cutting devices, which can fully realize automatic production with low cost and high efficiency.
- Slider adjustment structure
The slider adjustment is divided into manual adjustment and electric adjustment. This structure is convenient, safe, and fast, and the accuracy can reach 0.1mm.
- Novel design and environmental protection
The current punch press adopts advanced technology and design concepts and has the advantages of low noise, low energy consumption, and no pollution.
Punch Press Maintenance
Just like car maintenance, we also need to maintain the punch press regularly. Regularly maintained press machines have good performance and high work efficiency. We can start with the following four items to carry out comprehensive maintenance for our press equipment:
- Air piping: check whether there is any air leakage in each pipeline.
- Air valve and solenoid valve: Check whether the air valve and solenoid valve control is normal under proper operation.
- Balance cylinder: check whether the air is leaking, and check whether there is proper lubrication.
- Mold pad: Check if there is air leakage, check whether there is proper lubrication, and check whether the fixing screws of the mold pad are loose.
- Pressure gauge: Whether the pendulum needle of the press is normal.
- Electrical control: check the controller and its operation, and replace the defective controller; the loose part needs to be tightened; check whether the fuse is of the appropriate size, check whether the insulation part of the wire is intact, and replace the bad wire.
- Motor: Check whether the fixing screws of the motor and bracket are tightened.
- Buttons and foot switches: check these switches and buttons, and replace them immediately if they are defective.
- Relay: check contact wear, loose connection and disconnection, etc.
- The air lubrication components of the clutch: eliminate all water accumulation, check the condition of the single piece, and add lubricating oil to the correct position.
- Lubrication system: check whether the lubrication lines are broken or worn; check whether the accessories are leaky or damaged; check the oil level gauges to check whether the height of each oil level meets the standard. Under normal operating conditions, the oil immersed gear should be changed every three months. Clean the oil tank every six months (about 1500 hours).
- Plate: Confirm that no foreign matter is placed between the plate and the bed, confirm that the fixing screw of the plate has no loosening phenomenon, and confirm that the level of the plate is within the tolerance range.
- Clutch: Whether there is air leakage.
- Drive gear: Check whether the gear is properly lubricated, whether the slider adjustment parts are tightly fixed, whether there is no problem with the automatic brake, and check whether the worm and worm gear of the slider adjustment are accurate.
- Fixer and mold height indicator: check whether the fixer is invalid; check whether the mold height indicator is accurate.
- Motor drive: Check whether the motor shaft and pulley are loose, whether the belt and pulley are cracked, worn or deformed.
- Cleaning: Clean the inside and outside of the punch press to remove all foreign objects.