Before you choosing the model of injection molding machine, you need to know the definition of the important technical parameters of servo the injection molding machine,such as injection capacity,clamping force,injection pressure and speed,tie-bar space,etc.
It is defined as the maximum weight of the PS plastic material injected into the air. When the material of the plastic product is different from PS, the injection capacity is converted into: m = cb / 1.05 (where b is the density of another plastic, and c is the injection capacity expressed by PS plastic material).
The total weight of the product is preferably controlled within 85% of the injected capacity, and can try to choose the maximum value for the amorphous plastic , and choose Min. value for the high viscosity plastic.
It is defined as the final clamping force of the mold when the melt was injected into the cavity. The clamping force is usually calculated as the average pressure in the cavity * the projected area of the mold cavity. The average pressure inside the cavity is generally 20-40Mpa.
Injection Pressure and Rate
The injection pressure in the specification of the servo injection molding machine is the highest pressure in the barrel at the time of injection, not the highest pressure of the oil pressure in the injection system.
The relationship between the injection pressure and the oil pressure is inversely proportional to the ratio of the cross-sectional area of the screw to the area of the injection cylinder.
The injection rate refers to the amount of melt material injected out from the nozzle per unit time, and the theoretical value is the product of the cross-sectional area and the velocity in the barrel.
Mould Height and Max.Open stroke
The specifications of the servo injection moulding machine generally have a maximum mold thickness and a minimum mold thickness, which represent the thickness of the mold that the injection moulding machine can accommodate.
The mold open stroke of the injection molding machine has limitation, and the mold opening stoke required to take out the workpiece must be smaller than the maximum mold opening stroke of the injection moulding machine.
For injection molds with single-parting surface, the mold opening stroke is S>=H1+H2+5~10 (mm), H1 is the mold release distance (usually equal to the height of the mold core), and H2 is the workpiece height (including sprue system).
For the three-plate double-parting surface injection mold, the mold opening distance needs to increase the separation distance between the fixed template and the gate plate.
The ejection stroke should be reasonably selected according to the appearance of the product and the design structure of the mold. Generally,The ejection stroke of the machine is fixed. When ordering the machine, the ejection stroke is better to be large to suit a wider variety of products.
Tie-bar spare and other dimension
The length and width of the mold must be adapted to the size of mold platen of the injection molding machine and the distance between the tie-bar in order to ensure that the mold can be smoothly mounted to the template
When positioning, the center of the main sprue gate of the mold should be coincides with the center line of the nozzle of the barrel of injection molding machine;
The size of the positioning ring on the mold should be consistent with the size of the positioning hole on the template of the injection molding machine and the clearance fit should be used.
the spherical radius of the nozzle of the injection molding machine should match the spherical radius at the beginning of the main channel of the mold contact (R angle should be same);