There is no doubt that the input of the mold maker is the key to adjusting the project and the injection molding machine. However, familiarity with machine basics will help you make better design choices, more accurately predict project costs and production times, and even guide you to the injection molding partner that best meets your needs.

Types of Injection Molding Machine

There are three types of injection molding machines, categorized by drive/motor type – hydraulic, electric or hybrid.

Hydraulic Injection Molding Machine

Hydraulic injection molding machine is a large injection molding machine. The action of the hydraulic injection molding machine is to control each action of the injection molding machine by controlling the flow, pressure and direction of the hydraulic power source.

The full hydraulic injection molding machine uses a hydraulic valve to control the flow direction or flow of the high-pressure hydraulic oil extracted from the hydraulic pump to drive the piston rod or hydraulic motor of the hydraulic cylinder to complete linear reciprocating or rotary motion, but if the synchronization of each axis of the full hydraulic machine is to be realized action, an additional hydraulic accumulator must also be configured.

Hydraulic injection molding machines can use accumulators to achieve high-speed injection molding, and can also achieve special injection molding such as micro-foaming. The maximum clamping force of the hydraulic injection molding machine can reach 80,000kn, which can process larger injection parts.

Fully hydraulic injection molding machines use valves and oil motors to complete and control the injection movement. There are various types of actuators to choose from, and the clamping mechanism can adopt various clamping forms, which can better meet the processing requirements of various plastic products.

For more information, you can read this article: What is a Hydraulic Injection Molding Machine

Servo Injection Molding Machine

In a servo injection molding machine, a servo motor is used instead of an ordinary AC motor. Servo motors can be used for all drives of the machine, such as pump motors and injection drives.

In the application of the injection molding machine, the servo system receives the command signal from the computer to change the speed and torque of the servo motor to achieve precise speed and pressure control. During the execution process, the servo system detects the feedback through the rotary variable pressure encoder and pressure sensor. Correction and compensation are carried out, which means closed-loop control of speed and pressure, so that the injection molding machine runs stably and has a high product qualification rate.

Electric injection molding machine

All-electric injection molding machines use electric motors and screws to achieve their injection molding. The development of the actuator is restricted by the research and development level of the drive servo motor, so that the form of the actuator is less. In order to generate a larger clamping force for the servo motor, a toggle mechanism with a relatively small expansion force/large stroke is often used. Form of clamping mechanism. The limitation of the servo motor is in the clamping force. For example, the maximum clamping force of an all-electric injection molding machine is 10,000kN, which is more suitable for making small plastic products.

Weighing tonnage

Each of the injection molding machines mentioned above are still in use today. Although each iteration introduces certain technical advantages, tonnage (a measure of the force required to keep the tool closed during injection) remains a major factor in determining the size of the injection molding machine needed to produce a part.

Sizes can range from under 5 tons to over 4,000 tons. Considering such a wide range of possibilities, tonnage calculation is a necessary and critical step. Finding the right tonnage range takes into account the area of ​​the part, the type and viscosity of the plastic, and the “clamp factor”. Some molders do this by using industry-accepted estimating equations.

Influence of injection molding machine tonnage on injection molding

Injection molding is a complex dynamic system with multiple interacting factors – all of which affect performance, cost and quality. One of these factors is the injection molding machine tonnage calculation, also known as clamping force.

“Tonnage” is a measure of the force required to keep the tool closed during the injection process. This force is a major factor in determining the size of the injection molding machine required to produce the part. This may seem simple, but a lot depends on accurately determining the tonnage, which is why working with an experienced injection molding machine is crucial for producing complex plastic parts.