What are the precautions in the design of drawing die?
- The stretching material of the stretching die.
If the repeated test model does not meet the requirements, the material with good tensile properties can be replaced. Where there is quality, there is success. The commonly used specification is 08 steel, which is divided into boiling steel and stable steel. The price of boiling steel is low, the surface quality is good, but the angle is serious, it has a tendency of strain aging, and the appearance requirements are high.
Second, the surface finish of the drawing die.
In deep drawing, especially stainless steel plate and aluminum plate are easy to produce drawing when deep drawing, and tensile fracture is serious.
- Determine the blank size.
Wrinkling and less cracking is our principle. The blank positioning design should be accurate, which can be calculated according to the principles of blank area and wire drawing area (according to the trimming amount plus trimming). But the shape and process of wire drawing are more complex and sometimes thinner. Now, there are many 3D softwares that can perform unwrapped material calculations.
Answer: Test data.
For the reverse process of the drawing die, more work can be done after processing the falling edge dimensions of the blank before drawing. A product goes through many steps, and one process is usually blanking. After the mold design is completed, the convexity and concavity of the mold cannot be machined. The blank is first machined by wire cutting. If the blank is relatively large, it can be milled and clamped with a milling cutter), and then the size of the blank is determined by repeated tests of the subsequent wire drawing process, and then the die punch is processed.
Fourth, the tensile coefficient m.
The drawing coefficient is one of the main process parameters in the drawing process calculation, and is usually used to determine the drawing sequence and times. The relative thickness of the material, the stretching method (see the pressure-free edge ring), and the number of stretches are not easy to adjust during the casting process, please be careful. When choosing elongation factor M, find an engineering school. The factors affecting the tensile force coefficient m are: material properties, relative thickness of materials, stretching method (see no pressure side ring), stretching times, stretching speed, convex fillet, concave corner radius, lubrication, etc.
5. Heat treatment of die-drawing workpieces.
During the stretching process, when the workpiece is cold hardened due to cold plastic deformation, the plasticity decreases, the deformation resistance increases, the hardness increases, and the mold design is unreasonable, intermediate annealing should be performed to soften the metal and restore the plasticity. Low temperature annealing, ie recrystallization annealing, is usually used. There are two things to look out for when annealing: decarburization and oxidation. It’s about oxidation. The workpiece will be oxidized to scale, which has two disadvantages. Die wear will increase even if the effective thickness is thin. After all, we should be adding costs, so we should be careful about adding items and annealing!
The above introduces the relevant content of the drawing die design. Generally speaking, there are too many factors to consider in drawing die design. In addition, the size of the opening also plays a non-negligible role in the production test of the entire mold. I hope the above will help readers.