When Designing Injection Molds, You Should Pay Attention To These Parameters!

There are two templates on the injection molding machine, one does not move, called fixed template; the other can move, called moving template. The mold is fixed on the two templates by screws and pressure plates respectively. When the mold is opened, the movable platen of the injection molding machine moves, thereby driving the mold to open.

After the mold is manufactured, injection molding is carried out, the injection molding machine is loaded, and the product is started. However, there are many models of injection molding machines, and each injection molding machine has its own parameters. The design mold must be able to meet the requirements of the injection molding machine model provided by the customer, otherwise it will not be able to produce.

There are many design parameters of the injection molding machine. The following focuses on several parameters related to the mold.

1. Injection volume

The injection volume is the maximum mass value (or volume value) of the melt that the injection molding machine can inject at one time during production, which represents the maximum injection capacity of this type of injection molding machine. The amount of melt used in the designed mold is smaller than the injection amount of the injection molding machine. Otherwise, the product is dissatisfied and cannot be produced.

  2. Clamping force

The clamping force is the pressing force of the injection molding machine on the template when the mold is closed. The clamping force required by the molded product during molding must be less than the rated clamping force of the selected injection molding machine. Otherwise, the melted glue will easily run away from the parting surface, resulting in flash.

Clamping force = Clamping force constant × Projected area of the product: P=Kp×s

3. Tie rod spacing

There are four tie rods in the dead corners of the fixed platen and the movable platen of the injection molding machine. Their function is to ensure that the injection molding machine has sufficient strength and rigidity, and at the same time is responsible for sliding the template. But it tends to limit the overall size of the mold, because the mold is installed from the middle of the tie rod.

The dimensions of the mold cannot be larger than the distance between the tie rods for them at the same time. If the length of the mold exceeds the distance between the tie rods, check whether the mold is hoisted into the tie rod workshop by rotating. If the rotating hoisting cannot be carried out, only the mold size can be changed. , or replace the injection molding machine.

4. Nozzle size check

The nozzle head of the injection molding machine is generally spherical. When selecting the sprue sleeve, the spherical radius of the sprue sleeve should be consistent with the spherical radius of the nozzle. In order to prevent the high-pressure melt from overflowing from the contact gap between the nozzle and the sprue sleeve, the ball radius of the sprue sleeve should be generally larger than that of the nozzle, and the size of the small end of the sprue should also be slightly larger than the size of the nozzle hole, so that the nozzle can be connected to the sprue sleeve. Muzzle alignment is easier.

5. Checking of fixed ejector

Classification of ejector devices

(1). The center ejector is mechanically ejected

(2). Mechanical ejection of double ejector rods on both sides

(3). Hydraulic ejection of central ejector and mechanical ejection of double ejectors on both sides

(4). The hydraulic ejection of the central ejector rod is combined with other auxiliary oil cylinders