Improvement And Performance Evaluation Of The Multi-way Venting Device For Die Casting

In die casting process adopting the vacuum way to get a high vacuum cavityenvironment is an effective method to eliminate gas porosity defects.The castingsproduced by high vacuum die-casting can be used in high-temperature environment or bestrengthened through heat treatment. Based on the need of high vacuum die-castingtechnology, the self-developed New High Vacuum Die Casting (NHVDC) multi-wayvacuum system was improved and optimized according to the plant’s status. Then theimproved multi-way vacuum system had been used in casting production, to verify thereliability and effectiveness of the NHVDC and lay a good foundation to further promotethe industrial application.Since the detection and collection device signals relating to whether the vacuumventing process can be precisely controlled and considering its reliability and servicelifetime, magnetic scale was used to instead of rotary encoder as signal detection.Compared to rotary encoders, magnetic scale detecting pulse model is of a better accuracyand more adapted to the production of oil and aluminum scrap workshop environment.The PCI-1780data acquisition card was instead of high-speed counters of the FX2N seriesPLC. PCI-1780card can both count on the pulse signal and frequency counter functions,and in the vacuum process it could not only collect the shot-tip displacement signal butalso collect punch speed signal.Based on the requirements of Multi-way vacuum function, IPC configurationinterface and PLC control program have been redesigned. In this paper, more than20practical interfaces has been designed by the IPC configuration software, which can beapplied to a variety of die-cast models including ordinary, low-vacuum die-cast models,high-vacuum die-cast models and so on. The IPC control interface is easy to learn,meeting the needs of production applications. The PLC control program of the device hasbeen also redesigned according to high vacuum die casting process, which is better andmore reasonable.The improved multi-way vacuum system was applied in the die casting test andproduction verification through a kind of clutch housing as the object. The vacuum effect of cavity vacuum (one-way vacuum) was explored and displacement parameters andvacuum limits parameters were optimized. The porosity defects and internal qualities ofone-way cavity vacuum and multi-way vacuum under the same parameters were compared.Both of them have reached the X-ray inspection standard, but the porosity defects of thelatter one are better than the former one. Passing percentage under mass production bymulti-way vacuum system has increased by about2.25%, while it has reached97.5%.