1. According to the driving force of the slider, it can be divided into mechanical type and hydraulic type. Therefore, punch presses are divided into:
(1) Mechanical type punch press according to the driving force used.
(2) Hydraulic punch
Generally, mechanical punch is used for sheet metal stamping processing. Hydraulic punch presses are divided into hydraulic punch presses and hydraulic press presses depending on the liquid they use. Most hydraulic punch presses are used, while hydraulic punch presses are mostly used in large machinery or special machinery.
2. Classification according to the movement mode of the slider:
According to the movement mode of the slider, there are single-action, double-action, three-action punches, etc., but the most commonly used one at present is a slider. Single-action punches, double-action and three-action punches are mainly used in the drawing processing of automobile bodies and large-scale processing parts, and their quantities are very small.
3. Classification according to slider driving mechanism:
(1) Crankshaft punch
Punches that use a crankshaft mechanism are called crankshaft punches, as shown in Figure 1 Crankshaft type punch press, most mechanical punch presses use this mechanism. The most common reasons for using a crankshaft mechanism are that it is easy to manufacture, can accurately determine the lower end position of the stroke, and the slider motion curve is generally suitable for various processes. Therefore, this type of stamping is suitable for punching, bending, drawing, hot forging, warm forging, cold forging and almost all other punch processing.
(2) Crankshaft-less punch press
Crankshaft-less punch press is also called eccentric gear punch press. Figure 2 shows the eccentric gear punch press. Comparison of the functions of the crankshaft type punch press and the eccentric gear type punch press structure, as shown in Table 2, the eccentric gear type punch press structure is superior to the crankshaft structure in terms of shaft rigidity, lubrication, appearance, maintenance, etc., but the disadvantage is that the price is higher. When the stroke is long, the eccentric gear type punch is more advantageous. When the stroke of a special punching machine is short, the crankshaft punch is better. Therefore, small machines and high-speed punching presses are also the field of crankshaft punches.
(3) Toggle type punch press
Those that use a toggle mechanism on the slider drive are called toggle type punch presses, as shown in Figure 3. This type of punch has a unique slider motion curve in which the slider speed becomes very slow near the bottom dead center (compared with the crankshaft punch), as shown in Figure 4. It also accurately determines the position of the lower dead center of the stroke. Therefore, this type of punch is suitable for compression processing such as imprinting and finishing. It is currently most used for cold forging.
(4) Friction punch press
Punch presses that use friction transmission and screw mechanism on orbital drive are called friction punch presses. This kind of punch is most suitable for forging and crushing operations, and can also be used for bending, forming, drawing, etc. It has a versatile function 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 incorrect, and the need for skilled technology in use, it is now being gradually eliminated.
(5) Spiral punch
Those that use a screw mechanism on the slide drive mechanism are called spiral punches (or screw punches).
(6) Rack type punch press
Those that use a rack and pinion mechanism on the slider drive mechanism are called rack type punch presses. The spiral punch press has almost the same characteristics as the rack punch press, and its characteristics are roughly the same as those of the hydraulic punch press. It used to be used for extrusion of bushings, chips and other items, oil extraction, bundling, and extrusion of cartridge cases (hot room thinning processing), etc., but now it has been replaced by hydraulic punches, unless it is extremely special. No longer used except in situations where
(7) Connecting rod punch press
Punch presses that use various link mechanisms on the slide drive mechanism are called connecting rod punch presses. The purpose of using a linkage mechanism is to keep the stretching speed within limits during drawing processing, while shortening the processing cycle, and by reducing the speed change of drawing processing, speeding up the approach stroke from the top dead center to the starting point of processing. The speed of the return stroke from bottom dead center to top dead center allows it to have a shorter cycle than the crankshaft punch to improve productivity. This kind of punch has been used for deep extension of cylindrical containers since ancient times, and the bed surface is narrow. Recently, it is used for processing automobile body panels, and the bed surface is wide.
(8) Cam punch press
Punch presses that use a cam mechanism on the slider drive mechanism are called cam punch presses. The characteristic of this kind of punch is to make the appropriate cam shape so that the desired slider motion curve can be easily obtained. However, due to the nature of the cam mechanism, it is difficult to convey greater force, so the punch capacity is very small.
Precautions for safe use of high-speed punch press
■Before work
(1) Check the lubrication of each part and ensure that each lubrication circuit is fully lubricated;
(2) Check whether the mold installation is correct and reliable;
(3) Check whether the compressed air pressure is within the specified range;
(4) Be sure to The motor can be started only after the flywheel and clutch are disengaged;
(5) When starting the motor, check whether the rotation direction of the flywheel is the same as the rotation mark;
(6) Turn on the press Carry out several idle strokes to check the working conditions of the brake, clutch and control parts.
■During work
(1) Use a manual lubricating oil pump to pump lubricating oil to the lubrication point regularly. ;
(2) If you are not familiar with the performance of the press, you are not allowed to adjust the press without authorization;
(3) It is absolutely prohibited to punch two layers of sheets at the same time;
(4) If abnormal work is found, stop working immediately and check in time.
■After work
(1) Disengage the flywheel and clutch, cut off the power supply, and release the remaining air ;
(2) Wipe the press clean and apply anti-rust oil on the work surface;
(3) Keep records after each operation or maintenance.
Punch operating procedures
1. Punch workers must study, master the structure and performance of the punch, be familiar with the operating procedures and obtain an operating license before they can operate independently.
2. Use the safety protection and control devices on the punch machine correctly and do not dismantle them at will.
3. Check whether the transmission, connection, lubrication and other parts of the punch press and the protective and safety devices are normal. The screws for installing the mold must be firm and must not move.
4. The punch machine should be idle for 2-3 minutes before work. Check the flexibility of the foot brake and other control devices and confirm that it is normal before use. It must not be operated while sick.
5. The mold should be tight and firm, the upper and lower molds should be aligned to ensure the correct position, and the punch should be moved by hand (empty) to ensure that the mold is working in good condition.
6. Pay attention to lubrication before driving and remove all floating objects on the punch.
7. When the punch is moving or running and punching, the operator should stand appropriately, keep a certain distance between the hands and head and the punch, and always pay attention to the punch movement, and it is strictly forbidden to chat with others.
8. When punching short workpieces, use special tools and do not feed or pick up parts directly by hand.
9. When stamping or long parts, a safety support rack or other safety measures should be installed to avoid digging injuries.
10. When doing a single stroke, do not put your hands or feet on the hand or foot brakes. You must move (step on) each stroke to prevent accidents.
11. When two or more people are operating at the same time, the person responsible for moving (stepping) the gate must pay attention to the movements of the feeder. It is strictly prohibited to pick up the items and move (step) the gate at the same time.
12. Stop the machine in time when the work is completed, cut off the power, wipe the machine tool, and tidy up the environment.