Drawing die for different punches
The structure of the drawing die is determined according to the geometric shape, dimensional accuracy, material, yield and the press used. Tensile die is generally relatively simple, its structure according to the tensile direction there are forward tensile die and reverse tensile die and both positive and negative tensile die, according to the tensile process can be divided into single process tensile die, multi-process continuous tensile die and composite tensile die, which composite tensile die can be divided into blanking tensile die and blanking tensile punching die; According to the use of different presses can be divided into single action press with drawing die and double action press drawing die, called the habit of single action punch drawing die and double action punch drawing die.
A, single action punch drawing die
Tensile die for single action punch refers to the tensile die used in eccentric or crankshaft punch with only one slide motion. There are many kinds of drawing die according to the process.
1. Draw the die for the first time in a single process
A single process drawing die is a drawing die that completes only one process in one working stroke. The first drawing die of a single process has two kinds of blank holder and blank holder. Because of the simple structure of single process tensile die, it is generally not used guide device.
Forward drawing die structure without guide without holder. Forward drawing is a method of drawing the punch relative to the blank front. It is used for drawing the parts with thicker material and lower height. Because the deformation of the material is small, there is no need to bring the holder ring. When the mold is installed, the fixed clearance ring is first placed between the punch die and the concave die, the fixed clearance ring is taken out after the mold is tightened with the punch press, and then the blank of the pre-blanking is placed in the inner hole of the positioning plate. After stretching, the workpiece is scraped off from the hole end of the die by elastic opening.
The structure of a simple forward drawing die with an elastic blank holder is different in that the upper die is equipped with an elastic blank holder. When working, the blank is placed in the positioning ring and stretched under the action of punch. After stretching, the workpiece is scraped off from the bottom of the die 1 mouth.
The reverse drawing die with blank holder is more compact than the forward structure. The blank holder force is provided by the rubber cushion or spring of the lower die, and the stroke is larger. The pusher of the upper die is the forming die of the bottom of the drawing part. This structure has greater rigidity and ensures the forming quality of the bottom part. When working, the blank is positioned in the holder ring. Because the die adopts hard alloy inserts, it has long service life and is suitable for mass production.
2. Stretch the mold again
When the part needs to be drawn several times, the drawing die after the first time can be called the drawing die again.
Die for second drawing without guide post. When working, the semi-finished product formed in the previous process is placed on the punch for positioning. When the upper die with the punch slider down, first by forming the end face of the push plate pressed semi-finished flange surface, under the action of pressure, discharge plate with the upper die under pressure, the rubber buffer is compressed, the punch into the concave die of the inner surface of the hole tensile forming. When the upper die rises, the compressed rubber springs up and pushes the discharge plate, pushing the piece out of the punch. If the part remains in the die, the forming pusher is pushed under the action of spring compression to push the part out of the die.
Mobile die drawing die, it is suitable for high parts and punch stroke is small, not enough to take out the circular, square parts of the middle process stretching. The die and the positioning plate can be moved back and forth within the two guides. When working, first pull out the concave die, and then put the semi-finished parts of the previous process in the positioning plate, and then push the concave die to the stop pin position. The workpiece after tensile forming is removed by the scraper at the lower part of the die.
3. Composite drawing die
Compound drawing die refers to the punch in one stroke, in addition to complete the drawing, but also to complete other blanking work.
Blanking, drawing, punching composite die. The characteristics of the mold structure is that it has a high-precision guide device and an anti-wrinkle crimping ring device, which can ensure the blanking, stretching and punching clearance. It is suitable for the parts with thin stamping materials, but the grinding is difficult. In order to avoid waste sticking to the end face of the punch and accumulating in the hole of the punch, the punch is provided with a spring ejector rod to discharge waste from the inner hole of the screw in the buffer device. When working, the unloading plate first presses the material, and then by the convex and concave die, tensile die, punching punch and lower die, after the completion of blanking stretching, punching. When the upper die rises, the parts are pushed out by the roof under the action of the buffer's counter-elastic force. If the workpiece is left on the upper die, the workpiece is removed by the movable forming die.
Rectangular box blanking drawing die, it is suitable for high rectangular or high cylindrical parts drawing. There is no side, only two sides of the side of the residual material. When blanking, the ling material is automatically cut off by blanking flange, so there is no discharge plate.
