In the continuous severe economic environment, no cutting forming is a powerful means for enterprises to distance themselves from rivals and win in competition, and environmental protection is the theme of the 21st century, as the processing method of environmental protection will be the main direction of development. In order to realize these requirements, it is necessary to understand the comprehensive technology of the whole process from material to finished product. Punch press is one of the important technical elements. This paper introduces the basic characteristics of mechanical punch and the development direction of high-precision multi-function punch which is suitable for various forming technology developed in recent years.
Basic characteristics of punch press
The relationship between the characteristics of mechanical presses and the accuracy of products. The characteristics of the punch are mainly two, one is rigid, it includes longitudinal rigidity - slide block and the arch of the table and the elastic elongation of the frame; And transverse rigid eccentric load affects the horizontal displacement of sliding block. The other is the motion characteristics of the slider, including verticality, parallelism, straightness, etc., which has a great impact on the accuracy of the product. The accuracy of the product is not only related to the punch, it is related to the material, mold, lubrication and so on, can not only consider a certain factor. From the point of view of the elements of the press, the accuracy of the thickness direction of the product is related to longitudinal rigidity, while the deviation, bending or parallelism is related to transverse rigidity and motion curve characteristics. So improve these characteristics, product accuracy can be improved, mold life extension, production stability can also be improved.
The development trend of mechanical press
High rigidity and high function of general punch: the original C-shaped punch for general machine is also the pursuit of high precision and high function, from which the development of a gantry punch; Link press with slow speed near bottom dead end and SPM unaffected. This connecting rod punch in the drive gear and crankshaft between the involvement of two eccentric connecting rod, when the drive gear rotation, as a result of the connecting rod Angle changes, the crankshaft does not equal speed movement. The connecting rod mechanism is different from other connecting rod mechanisms in that the joint point of the compression part is less and the comprehensive clearance is small. As shown in FIG. 8, the connecting rod mechanism has a higher torque capacity than the toggle mechanism and can achieve a higher forming position at the bottom dead center.
CNC punch: CNC punch with CNC control system, according to the processing method of the need for arbitrary set slider movement and speed.
1, screw type CNC punch
Servo machine is the use of AC servo motor through the screw drive slider, forming the position of the bottom dead point through the position reading device to provide data to the position control device for control. Therefore, mechanical thermal expansion and elastic deformation will not affect the accuracy of the product, adjust the most suitable slider movement mode and control the location of the bottom dead point in extremely small units. So suitable for high precision and high function of no cutting forming screw servo punch using hydraulic motor and energy storage device torque control form, the position control of the bottom dead point can reach micron level, is energy saving and environmental protection requirements of the machine.
2. Crankshaft servo punch press
Crankshaft punch and AC servo motor combination of CNC punch. This press uses servo motors instead of clutch brakes and flywheels. This press has the characteristics of servo press which can be set arbitrarily with slider motion mode, and has the torque characteristics of ordinary mechanical press as shown in Figure 3. But its working energy does not decrease in the low speed zone.
3, complex forming punch
Complex dynamic forming is a powerful means of non - cutting forming. Block forging in cold chamber forging is an example of controlling the plastic flow of material by controlling the action and time diagram of multiple punches and die. The precision and formability of the products can be improved, and even the number of processes can be shortened.
Complex dynamic forming can be roughly divided into two categories: attach importance to the generality of punch using complex dynamic die frame complex dynamic forming; A variety of production moulds are easily assembled and disassembled using the forming of a compound punch. Recently, not only in the forging process, but also in the plate gold forming and forging composite forming diversification and ability improvement at the same time, it is required that the punch not only has multi-action performance, but also must have high versatility.
4, block forging press
The forming of star wheel and cross joint has widely used block forging die and general forging punch. Other closed forging presses that save piping time during die assembly can be divided into two types: these functions are all in the punch press and the upper and lower cylinders are on the punch press and the coordinating mechanism is on the die seat.
5, plate forging press
With the popularity of sheet metal forging and pressing forming, it is required that forging punch can carry out deep drawing forming or shorten the number of projects, so it is required that the slider and the table must be with oil cylinder. The original block forging almost adopts high capacity atmospheric pressure action, plate forging requires not only atmospheric pressure action which is suitable to the working method, but also sequential action, self-locking and other functions.
6, gear forming punch
Compound hydraulic press for helical gear forming is shown in Figure 19. This punch has a sliding drive, two in the slide block, two in the table, a total of 5 driving sources all share a hydraulic drive device.
Ordinary punch