The working principle and the classification, punch
Principle 1, punch:
The design principle is to press a circular motion into linear motion. From the main motor output, drives the flywheel, clutch driven by gear, crankshaft, connecting rod (or eccentric gear) running, to achieve the linear motion of the slider, from the main motor to the connecting rod motion into circular motion. A switching point circular motion and linear motion is required between link and the slider, the design there are two kinds of mechanism, a ball, a pin type (cylindrical), through the mechanism of the circular motion into linear motion of the slider.
Punch exerts pressure on the material, the plastic deformation, and the shape and precision required, and therefore must be matched with a group of mould (divided into upper and lower moulds), the material in the meantime, by the pressure of the machine, the machining deformation, imposed on the material stress reaction, the absorbed by the punch machine body.
Classification of two, punch:
1, according to the slider driving force can be divided into mechanical and hydraulic press two, so its use is divided into driving force:
(1) a mechanical press
(2) hydraulic press
General sheet metal stamping processing, most of the use of mechanical press. Hydraulic press according to its use different kinds of liquid, a hydraulic press and hydraulic press, hydraulic press used at present majority, hydraulic presses are used for large machine or special machine.
In 2 way classification: according to the movement of the slider slider motion classification of single action, double action, three movable punch, but the most widely used as a block of single punch, double acting and three punch is mainly used in drawing automotive body and large work piece, the number is very small.
3 in accordance with the slider driving mechanism classification:
(1) the crank type press
Press crankshaft mechanism is called the Crankshaft Press, most of the use of the mechanism of mechanical press. Reasons for using crank mechanism is the largest, easy to manufacture, can correctly decide travel end position and slide motion curve, generally applicable to a variety of processing. Therefore, stamping and suitable for this type of cutting, bending, stretching, hot forging, warm forging, cold forging and almost all the other punch processing.
(2) crankless press
Crankless press also called eccentric punch. Comparison of the crankshaft press and eccentric gear punch two tectonic function: the stiffness of the shaft, lubricating, appearance, maintenance of eccentric gear punch structure is better than the crankshaft structure, the weakness is the high price. The trip is longer, more favorable eccentric gear punch, and such as stamping stroke cut special machine short situation, is the crank press is better, so small and high speed punching with punch and crank press field.
(3) the toggle press
Use the slider to drive the toggle mechanism called the toggle press. This punch is provided with the slide speed in BDC will become very slow (and crank press) unique slide motion curve. And accurately determining the stroke the bottom dead center, therefore, this kind of punch for stamping machining and finish machining the compression, up to now the use of cold forging.
(4) the friction press
Press friction drive and screw mechanism in the track's driver called friction press. This punch is most suitable for forging, crushing operation, also can use processing in bending, forming, stretching, which has multiple functional, due to the low price, 60 years ago and has been widely used. Unable to determine the position of the poor, the machining accuracy, stroke production speed is slow, control error will lead to technical disadvantages such as load, skilled use, has now been eliminated.
(5) screw press
In the slider driven screw mechanism mechanism called screw press (or screw press) is now rarely used.
(6) the rack punch
In the slide drive using the rack and pinion mechanism mechanism called rack punch. Screw press and rack punch has almost the same characteristics, its characteristics and hydraulic punch roughly the same. Before is used for pressing sleeve, debris and other items, packaging, extrusion, pressing and shell of pressure (hot extrusion sheet processing), but has now been replaced by hydraulic press, unless very special circumstances no longer use outside.
(7) connecting rod type punch
In the slide block drives the punch using various linkage mechanism is called the link type punch. Objective the use of linkage mechanisms, in drawing while stretching speed on limits, and shorten the processing cycle, by reducing the drawing velocity, speed to processing from the top dead center starting point close to the stroke and from the bottom dead center first dead returning journey, which is shorter than the period crank press, to increase production. This kind of punch since ancient times has been used for the deep drawing of cylindrical container, bed narrow table, it has recently been used for processing, automobile body panel bed board wide.
(8) the cam punch
In the slide drive press cam mechanisms mechanism called cam punch. Characteristics of this punch is to make the cam shape appropriate, get the slider motion curves are so easily. But due to the nature of the cam mechanism is difficult to convey a great force, so this kind of punch capacity is very small. General clothing industry commonly used.