For drawing dies, especially for deep drawing and multiple drawing dies, many business departments of die factories are not willing to quote and accept orders. Because drawing dies are generally impossible to follow the theory completely, many things are right in theory, that is, they cannot achieve the expected test results, which requires fitters to debug many times and takes a lot of time to debug the dies. The following is a summary of some practical drawing die design experience for reference:
Generally, the material of drawing parts is the brand of steel mill designated by the customer, but the same material may have different models, for example, cold rolled plates are divided into 08Al, 08, 08F, 10, 15 and 20 steels. If the selection is improper, qualified products may not be designed.
Second. open blank material
Most of the regular and simple-shaped revolving stretch products belong to non-thinning stretch and can be directly determined according to the principle of unchanged area before and after stretching. If it is a drawing piece with a very complicated shape, sometimes the material may flow seriously and become thin. Generally, it is impossible to accurately calculate its opening size. It is predicted by 3D expansion (CAE analysis and simulation through AutoForm), which is also the so-called sample.
Three. tensile calculation coefficient
Tensile coefficient is very important. A tensile part needs to be stretched in several steps to ensure no cracking, wrinkling and other problems. The tensile coefficient formula should be used for calculation. It is one of the most important process parameters in drawing process accounting. It is generally used to determine the drawing order and times.
However, the tensile coefficient is not fixed. There are many factors that affect the tensile coefficient m, including material type, thickness, tensile structure type, tensile times, tensile speed, excessive arc size of the tensile insert, etc. However, it is generally possible to look up tables and make rough calculations.
Tensile parts often encounter problems such as cracking and wrinkling during die debugging. If there is tension crack, the problem of material flow needs to be considered. Lubricating oil can be coated on the female die (not on the male die), or 0.013--0.018mm thin film (that is, winding film commonly used by fitters) can be coated on the side of the product close to the female die.
"More wrinkles, less cracks", according to this method to judge the flow of materials. Adjustment scheme: adjust the pressure of the blank holder ring, increase the drawbead, change the arc excess radius of the upper and lower die inserts, and cut the process opening on the workpiece, etc.
In short, the drawing parts are the mold types with relatively high technical content. It is a challenge to design, process, assemble and debug, and needs to be very cautious.
Yixin Precision Metal and Plastic Ltd, which has 16 quality inspection channels, has carried out strict control on the raw material feeding from the source, and has also carried out careful review on the design of stamping dies. Until the box is sealed and shipped, 16 tests will be conducted to ensure your satisfaction with the results.
Please feel free to contact us if you need.