Research On Variable Speed Blanking Process Of Thick Metal Plate Based On Servo Press

Blanking is one of the most important stamping process, and it accounts for about50%-60%of the whole stamping process. In the blanking process, it usually produces strong vibration and noise, which not only seriously impact on people’s health, but also affect the quality of parts and reduce stamping equipment and tool life. Since most blanking process is on by the ordinary crank press, it is difficult to reduce vibration and blanking noise and improve parts quality by changing the blanking speed. Nowadays, with the development of society, energy conservation, environmental protection and other green manufacturing technology has become the focus. For ordinary blanking process, because of high energy consumption and blanking noise, it makes people constantly develop new blanking process. In the beginning of this century, the emergence of servo press provided a new situation to solve that problem. People are gradually shifting their focus to blanking process based on servo press.The new press directly drive and control slider movement by servo motor, and real-time control punching loads and loading speed according to process needs. Therefore, its work performance and process applicability are greatly improved.In this thesis, the thick plate of Q235A、20stee、A6061aluminum and SUS304stainless steel are studied as the research objects. The finite element models are found through DEDOEM-2D and crack propagation material plastic flow、fracture process、 blanking parts fracture surface and blanking noise are studied under different blanking clearance and speed through the method of combining the theoretical analysis and experiment and finite element simulation. The main contents and conclusions are as follows.1.Through the theoretical analysis, the valid finite element model is established, and equivalent stress, equivalent strain were analyzed, and also blanking force curves, the maximum blanking force and fracture surface were investigated under different blanking clearance and speed. The results show that with blanking clearance increases, the maximum blanking force gradually reduces and burnish height decreases and rollover height increases; with blanking speed increases, the maximum blanking force increases, burnish height reduces and rollover increases. Simulation results can provide a theoretical basis for generation of cracks, as well as provide evidence for variable speed blanking experiments.2. The material plastic flow pattern in the blanking process was studied and initial fracture point and fracture interval of four materials under four different clearances. The experimental results can provide basis for setting variable speed curve based on servo press. Also the impact of blanking clearance and speed on fracture surface were studied. The experimental results are basically consistent with simulation results.3. The blanking process noise was studied by setting different motion curve based on servo press. The results show that the blanking noise increases with the blanking speed increasing. The Impact of blanking speed on blanking noise in case of20steel Q235A and A6061aluminum is significant, but blanking speed is not sensitive of SUS304, also and its noise level is very high. Compared the maintaining pressure motion with the corresponding crank constant movement, the reduction of maximum blanking noise is more than8dB in case of20、Q235A and A6061. Meanwhile, blanking clearance is an important factor in affecting blanking noise. Compared maintaining pressure motion and conventional blanking model, the reduction of noise is about20dB in case of Q235A in the clearance of7%t(t is plate thick). In a certain range of maintaining time, extension of maintaining time can effectively reduce blanking noise. Considering of reduction of blanking noise and production efficiency, the maintaining time of0.2s is more reasonable.In this thesis, the blanking processes are studied based on servo press under variable speed conditions. It can not only enrich blanking techniques and theory, but also have an important practical significance to improve the stamping equipment and tool life, and also provide a solid theoretical and practical basis for the application of the new servo press.