Development And Application Of Key Technology For Vacuum Die-casting Auxiliary Equipment

Die casting is a high efficiency and low cost precision forming technology which iswidely used in many fields of such as automotive, communications, consumer electronicsetc. But the gases likely to be involved in liquid metal through die casting. This will leadto gas porosity defects that deteriorate the casting quality. The gas porosity defects caneffectively eliminated by vacuum die casting. At present, the research and developmentof vacuum valve and the vacuum control system which is the core equipment of vacuumdie-casting obtained a lot of achievements, while rarely for the vacuum die-castingauxiliary equipment research. Based on this reason, the vacuum die-casting auxiliaryequipment need be developed. The task in this paper including design a vacuum diecasting plunger and further development for die casting internal gas quantitativedetection device which independent research and development by our laboratory.In this paper, the new plunger tip and plunger rod are designed with new mechanicalstructure, including sealing ring, thread flume, distributor. Seal ring is used for sealingplunger tip and shot sleeve to achieve high vacuum die casting. Thread flume can beapplied to improve the cooling effect. The distributor was designed to spray water-basedlubricants evenly which can reduce the waste of water-based lubricants.Improved the cover structure of vacuum chamber to increase a high vacuumbutterfly valve which make the vacuum chamber of the aluminum die casting internal gasconcentration device has a better sealing effect and adjust the vacuum gauge pipeposition. Used the YanHua intelligent module to acquire the pressure signal of vacuumchamber, and used the Configuration software to design a standard curve pretreatment,the measured curve and the leakage curve to processing the acquired data. The improveddevice had measured the standard curves at660℃,680℃,700℃, which has a goodlinear. The cures are managed by linear fitting get the equation as follows: P=9.596V、 P=9.927V、 P=10.280V At the same time, the improved device had been used in measuring a cam shaftframe and engine gear chamber parts compared their common die casting part andvacuum die casting part in divided position. The equation of gas standard curve under700℃is ΔP=10.28V used for conversion. The final measurement results show that thegas content of near the casting gate and overflow groove position is higher than themiddle position of casting. In addition, volume containing of corresponding dividedposition vacuum die casting lower than ordinary.