1. According to the driving force of the slider, it can be divided into two types: mechanical and hydraulic, so punch presses are divided into different driving forces according to their use:
(1) Mechanical punch
(2) Hydraulic punch
For general sheet metal stamping processing, most of them use mechanical punching machines. Depending on the liquid used, hydraulic presses include hydraulic presses and hydraulic presses. The majority of hydraulic presses are hydraulic presses, while hydraulic presses are mostly used for large machinery or special machinery.
2. Classified according to the movement of the slider:
There are single-action, double-action, and three-action punch presses according to the movement of the slider. The only one currently used is the single-action punch press with one slider. The double-action and triple-action punch presses are mainly used for the extension of automobile bodies and large machining parts. The number of processing is very small.
3. According to the classification of slider drive mechanism:
(1) Crankshaft punch
A punch using a crankshaft mechanism is called a crankshaft punch, as shown in Figure 1 is a crankshaft punch. Most mechanical punches use this mechanism. The reason for using crankshaft mechanism most is that it is easy to manufacture, can accurately determine the position of the lower end of the stroke, and the movement curve of the slider is generally suitable for various processing. Therefore, this type of stamping is suitable for punching, bending, stretching, hot forging, warm forging, cold forging and almost all other punching processes.
(2) No crankshaft punch
No crankshaft punch is also called eccentric gear punch. Figure 2 is an eccentric gear punch. Comparing the functions of the crankshaft punch and the eccentric gear punch, as shown in Table 2, the eccentric gear punch is better than the crankshaft in terms of shaft rigidity, lubrication, appearance, and maintenance. The disadvantage is that the price is higher. When the stroke is longer, the eccentric gear punch is more advantageous, and when the stroke of the special punching machine is short, the crankshaft punch is better. Therefore, small machines and high-speed punching punches are also in the field of crankshaft punches.
(3) Toggle punch
Those who use the toggle mechanism on the slider drive are called toggle punches, as shown in Figure 3. This type of punch has a unique slider movement curve in which the speed of the slider near the bottom dead center becomes very slow (compared with a crankshaft punch), as shown in Figure 4. Moreover, the bottom dead center position of the stroke is accurately determined. Therefore, this type of punch is suitable for compression processing such as embossing and finishing, and cold forging is currently used the most.
(4) Friction punch
A punch that uses friction transmission and a screw mechanism on the track drive is called a friction punch. This type of punch is most suitable for forging and crushing operations, and can also be used for processing such as bending, forming, and stretching. It has versatile functions because of its low price and was widely used before the war. Due to the inability to determine the position of the lower end of the stroke, poor processing accuracy, slow production speed, overload when control operations are wrong, and the need for skilled technology in use, it is gradually being eliminated.
(5) Spiral punch
Those who use the screw mechanism on the slider drive mechanism are called screw punches (or screw punches).
(6) Rack punch
Those who use rack and pinion mechanisms on the slider drive mechanism are called rack punches. Spiral punches have almost the same characteristics as rack punches, and their characteristics are almost the same as those of hydraulic punches. It used to be used to press bushings, crumbs and other items, such as extrusion, oil extraction, bundling, and the extrusion of cartridge cases (hot room squeezing processing), but now it has been replaced by hydraulic presses, unless extremely special No longer used outside of the situation.
(7) Link punch
A punch that uses various linkage mechanisms on the slider drive mechanism is called a linkage punch. The purpose of using the linkage mechanism is to keep the drawing speed within the limit while shortening the processing cycle during the drawing process, and to reduce the speed change of the drawing process to speed up the approach stroke and the distance from the top dead center to the processing start point. The speed of the return stroke from bottom dead center to top dead center makes it have a shorter cycle than crankshaft punching machine to improve productivity. This type of punch has been used for deep extension of cylindrical containers since ancient times, and the bed surface is relatively narrow. Recently, it has been used for the processing of automobile body panels and the bed surface is relatively wide.
(8) Cam punch
A punch that uses a cam mechanism on the slider drive mechanism is called a cam punch. The feature of this punch is to make an appropriate cam shape so that the desired slider movement curve can be easily obtained. However, due to the nature of the cam mechanism, it is difficult to convey a large force, so the punching capacity is very small.
Precautions for the safe use of high-speed punches
(1) Check the lubrication condition of each part, and make each lubricating circuit be 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) The flywheel and clutch must be disengaged before the motor can be turned on;
(5) When the motor is started, check whether the rotation direction of the flywheel is the same as the rotation mark;
(6) Let the press perform several idle strokes to check the working conditions of the brakes, clutches and operating parts.
(1) A manual lubricating oil pump should be used to pump lubricating oil to the lubrication point at regular intervals;
(2) When the performance of the press is not familiar, it is not allowed to adjust the press without authorization;
(3) It is absolutely forbidden to punch two layers of sheets at the same time;
(4) If the work is found to be abnormal, stop work immediately and check in time.
(1) Disconnect 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) Make a record after each operation or maintenance.
Punch operating procedures
1. The punch worker must have studied, master the structure and performance of the punch, be familiar with the operating procedures and obtain operating permits before they can operate independently.
2. Use the safety protection and control device of the punch correctly, and do not dismantle it arbitrarily.
3. Check whether the transmission, connection, lubrication and other parts of the punch and the protective safety device are normal. The screws of the mold must be firm and must not be moved.
4. The punch should be run dry for 2-3 minutes before working. Check the flexibility of the foot brake and other control devices, and use it after confirming that it is normal. It should not run with illness.
5. The mold must be firm and firm, the upper and lower molds are aligned to ensure that the position is correct, and the punch is moved by hand to test punch (empty cart) to ensure that the mold is in good condition.
6. Pay attention to lubrication before driving, and remove all floating objects on the punch.
7. When the punch is taken out or is running and punching, the operator should stand properly, keep a certain distance between the hand 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 and small workpieces, special tools should be used, and it is not allowed to directly feed or pick up parts by hand.
9. When punching or long-body parts, safety racks should be set or other safety measures should be taken to avoid digging and injury.
10. When single punching, the hands and feet are not allowed to be placed on the hand and foot brakes, and they must be lifted (stepped) once to prevent accidents.
11. When two or more people operate together, the person responsible for moving (stepping) the gate must pay attention to the actions of the feeder. It is strictly forbidden to pick up the parts and move (step) the gate at the same time.
12. Stop in time at the end of the work, cut off the power supply, wipe the machine tool, and clean up the environment.