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How to choose Hydraulic-electric injection molding machine

Mar 06, 2020

There are currently many manufacturers producing hybrid electric injection machines, and the technical specifications, models and quality classes of hybrid electric injection machines are also different. The user must select the specifications and quality ratings of the plastic machine according to injection molding products in combination with current and long-term interests.


When buying, users must first clearly indicate which products, materials, volume, grams, annual production volume and other factors (for example, manufacturers of plastic barrels and manufacturers of precision plastic parts for tools. After choosing a conceptual road), you can choose the technical characteristics of the hybrid injection machine according to the following important technical parameters and important components of the injection molding machine.

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Injection Quantity:

It is defined as the most important for air-filled PS plastic. It is one of the most commonly used parameters of a hybrid injection molding machine. When the material of plastic products is different from PS, the injection quantity specified in our company’s specifications can be used after conversion: m = ch / 1.05 (where b is the plastic density and c is the injection quantity expressed by PS plastic).

For example: PP density is 0.90 & / cm3, and the injection volume parameter of the TYD80 hybrid injection molding machine manufactured by our company is 124 &. Therefore, the injection volume when this machine uses polypropylene as raw material is 124x0.9 / 1.05 = 106. According to actual experience, the total weight of the product is best controlled within 85% of the injection volume, which can be large for β-crystalline plastics and less for high viscosity plastics.


Clamping force:

It is defined as the final clamping force of the mold when the mold is closed and the mold is injected into the cavity. This is one of the most commonly used parameters of injection molding machines.

When the clamping force is insufficient, a “flash” occurs. When choosing a model, make sure that the clamping force required to process the product is less than the clamping force of the machine. The locking force is usually calculated as the product of the average pressure in the cavity and the projected area of the cavity.


The average pressure in the cavity is usually 20-40 MPa, which is determined in accordance with such factors as the characteristics of the plastic, product requirements and the ratio of the product flow length. The exact clamping force can be calculated by computer simulation in the design of the mold.


Injection Pressure and Injection Rate:

In the technical specifications of the oil-electric hybrid injection molding machine, the injection pressure refers to the highest pressure in the cylinder during injection, and not to the highest pressure in the injection system. The relationship between injection pressure and oil pressure is inversely proportional to the cross-sectional area of the screw and injection cylinder. The ratio of areas.


For the technical characteristics of the injection molding machine, there are three different types of screws with the same clamping force. Among them, screw A has the smallest diameter, and screw C has the largest. Relatively speaking, screw A can achieve maximum injection pressure.


Injection rate refers to the amount of melt ejected from the nozzle per unit time, and its theoretical value is the product of the cross-sectional area in the cylinder and speed. Currently, the requirements for injection speed in the injection molding process tend to be not only high in cost, but also require the development of a program (i.e., gradual injection) during the injection process.


In particular, in accordance with the characteristics of plastic raw materials and processed products, the state of the melt flow during mold filling should be effectively monitored.


Mold thickness and maximum mold opening stroke:

The specifications of a hybrid injection molding machine typically have a maximum mold thickness and a minimum mold thickness (or module) that represent the thickness of the mold that the injection molding machine can accommodate.


The mold transfer mold of the hybrid injection machine is made, and the distance required to remove the mold should be less than the maximum mold opening of the injection mold. For injection molds with a single dividing surface, the opening stroke of the mold is S≥H1 + H2 + 5-10 (mm), where H1 is the dismantling distance (usually equal to the height of the mold core, the product can be removed Demolition. The distance H1 depends on the specific situation, so that the workpiece can be pulled out smoothly.

H2 - part height (including casting system). For double-socket casting molds with three types and point-lock molds, the mold opening distance should increase the distance between the fixed mold and the gate plate. This distance