The injection molding machine heats the plastic and applies high pressure to the molten plastic to eject it and fill the mold cavity. Recently, many friends asked injection molding machine What is the function of pressure maintaining in? Next, Liansheng Precision Editor will give you an answer:

　　 Pressure holding function of injection molding machine:

Pressure holding is used to prevent the product from shrinking. For some products that require fast injection speed and long cooling time, pressure holding is required. Pressure holding is generally low speed and high pressure, otherwise it is invalid.

The injection pressure has both pressure and speed. Holding pressure only affects pressure and speed. The injection pressure is to put the molten material into the mold at the required speed. All injection cylinders move forward at the pressure and speed you set. When the cylinder moves forward, the oil continues to flow into the cylinder. The holding pressure is the pressure that the oil sets for the cylinder, but the oil no longer increases. As the piston in the cylinder moves forward, the pressure becomes less and less. The pressure will not decrease until the material cools down. The pressure and speed of maintaining pressure must be less than the injection pressure and speed.

　　 Functions of pressure maintaining switch of injection molding machine:

When the injection process is completed, the cavity is filled and melted. At this point, at the top of the injection screw, because the cooling effect of the mold is at a lower temperature, the injection mold cavity of the molten material shrinks, which is the density of the product quality and prevents the melt from flowing in the cavity and shrinking to compensate for the product. During injection, a certain pressure must be maintained in the hydraulic cylinder, Push the screw to continue to apply pressure on the molten material in the mold until the melt is cooled and sealed at the gate. At this time, the pressure exerted by the screw on the molten material is called the holding pressure, also called the secondary pressure. During pressure maintaining, the screw may move forward slightly due to feeding.

When the molten material in the mold cavity loses the possibility of backflow from the gate, the internal pressure holding can be relieved (at this time, the high pressure in the mold closing hydraulic cylinder can also be relieved) (that is, the gate can be closed), and the hydraulic cylinder can be injected to cool and shape the product in the mold.