Low pressure casting process is a casting method between pressure casting and gravity casting.When the holding furnace is full of metal liquid,we put dry compressed air into it,which acts on the metal liquid with a certain temperature.The dry compressed air lets metal liquid into sand mold cavity from lift tube. When the metal liquid is full of mold cavity, the pressure build up. Holding the pressure till the casting is complete freezing.then relieve pressure.the unfreezing metal liquid is back to holding furnace in the lift tube and pouring gate. This is a casting process. When open the box we can get the castings which we want.
Low-pressure sand casting machine consists of two pieces: holding furnace and liquid surface pressure control system. The furnace cover of holding furnace is used for work table for sand box. The prepared sand box fixed on the cover of holding furnace directly and then pressure casting.
Operation Process as follows：
When the prepared sand box is closed, the operator put it on the worktable where is up on the holding furnace. When the sand box connects the riser tube and tightly sealed, the system starts pressure casting. The whole process which includes lift, mold filling, pressure boost, holding, pres-relief stage, is fully automated. When all finish, we can take sand box away from worktable and then the cast part is removed from the mold.
Fluid surface forcing control system adopts the high performance proportional valve +precision pressure sensors，which can examine the pressure of holding furnace and control real-time and closed loop feedback by PID accommodation mode. The system has multi-linear pressure, leakage compensation for holding furnace and leakage compensation for liquid surface. The setting add-pressure craft’s curve can be tracked automatically.
High precision control of pressure ensures the low press die casting process stable properties and good consistency.
You may select computer or HMI as mainframe Monitor System. With database technology, all the pressure process data save in database include each practically pouring process data. So we can query and analysis all the history process data to improve the process quality so much.