How to choose a suitable injection molding machine? From the machine itself and plastic product!

2022-08-11 17:25:36

The three keys of an injection molding factory were introduced before, namely "equipment", "mold", and "management", of which "equipment" is the injection molding machine. A suitable injection molding machine focuses on creating value for customers. Therefore, the injection molding machine needs to have stable production, simple operation, and convenient maintenance. The critical point is to meet the needs of customers in production and create value for customers.

Injection molding machines can be divided into two types according to clamping: horizontal injection machines and vertical injection machines. Taking into account the different needs of customers in production, Huarong continues to develop and improve the product line of horizontal injection machines and vertical injection machines according to different plastic characteristics, plastic product characteristics, production needs, etc., to meet the needs of customers for the production of different plastic products.


Due to different production needs, how to choose a suitable injection molding machine?

The following will be cut through two aspects so that you can have a direction to think about how to choose a suitable injection molding machine. 
The two aspects are injection molding machines and plastic products.


Injection Molding Machine - Clamping Unit, Injection Unit, Power Unit

When deciding on an injection molding machine, you can consider three directions:

  1. Clamping unit: the size of the mechanism 
    Determines whether the mold can be put into the injection molding machine, and when the plastic product is completed, whether it can be ejected and automatically dropped.
  2. Injection unit: the plasticizing ability 
    Determines whether the injection volume and the ability to plasticize plastic are sufficient.
  3. Power system
    Determines whether the injection molding machine's power is sufficient.


When choosing a machine, firstly the clamping unit (size of the mechanism), secondly the injection unit (plasticizing capacity), and finally the power system. From these three aspects so you can choose the right injection molding machine.


1. Clamping unit: The size of the mechanism

The source of the mechanism size in the clamping unit is the size of the accommodating mold, and the key points to be considered include the tie bar distance, opening stroke, and mold thickness of the injection molding machine.

  • The tie bar distance refers to the length of the distance between the four tie bar , which directly affects the installation of the mold, and whether the space can accommodate the size of the mold.


  • The mold opening stroke refers to the displacement distance from that the movable platen is bent and straightened to the greatest extent by the toggle. This distance affects whether there is enough space for the plastic product to fall automatically after being ejected.
    Therefore, it is recommended that the mold opening stroke is greater than twice the height of the plastic product. If it is a cold runner mold with a sprue, the mold opening stroke is recommended to be greater than the sum of the sprue length and twice the height of the plastic product.
*Remarks: Toggle is a kind of clamping.


  • The mold thickness refers to the difference between the thickest and thinnest molds that can be clamped. When selecting, refer to: maximum mold thickness (mold upper limit) ≧ mold thickness ≧ minimum mold thickness (mold lower limit).


2. Injection unit (plasticizing ability)

  • Regarding the plasticizing ability in the injection unit, the key points to be considered include the shot weight, injection pressure, and injection rate of the injection molding machine.
  • The shot weight is the injection volume multiplied by the plastic melt density (g=vρ). The shot weight on the specification sheet of the injection molding machine is generally calculated based on the PS material first. Since the unit conversion and safety factor of different materials need to be considered when evaluating the shot weight, it is recommended that "plastic", "product weight," and "mold cavities" can be provided to the manufacturer of the injection molding machine for evaluating whether the injection unit meets the production requirements.
  • The injection pressure needs to be considered from the characteristics of the plastic, such as the fluidity, shrinkage rate and product properties of the plastic. The setting of injection pressure should generally be high and not low. A higher injection pressure is helpful for the injection molding of engineering plastics.
  • The injection rate refers to the maximum volume of molten plastic injected from the nozzle in a unit time, and also represents the speed of the molten plastic passing through the nozzle. In theory, the product with thinner thickness has a faster injection rate, because the plastic will rapidly cool in the mold and lose its fluidity, resulting in insufficient plastic filling.


3. Power system

  • The size of the power system depends on the relational formula between the injection pressure and the injection rate. Sometimes customers have the production requirements of "high injection rate" or "fast production cycle time", the motor and pump can be increased to achieve the desired effect under the condition of constant system pressure.
  • To avoid unnecessary energy loss, the power system can choose the servo hybrid power control system, which can precisely control the pressure and flow of each process, how much the system outputs as much as the actual demand, and there will be no excess energy consumption to achieve the effect of energy saving.
  • Advantages of Servo Hybrid System
    1. The system has high precision, fast response and good stability.
    2. High energy saving ratio, low noise and less cooling water demand.
    3. The oil temperature is not easy to rise, and the hydraulic oil has a long service life.
    4. Long service life and low maintenance cost.
    5. Wide range of practicability, covering all plastic products.
Patent No. M328970 for Servo Hybrid Power Control System of Injection Molding Machine


Product Information – Conditions, Dimensions & Weights, Plastics

At present, the plastic products on the market are more and more diverse. From the use of raw materials, product design, etc., the performance of general standard injection molding machines may not meet the needs. How to help customers choose a suitable injection molding machine is even more important.

1. Conditions determine the model

There are many types of injection molding machines. According to the conditions of product molding, the choice of models may be different, so you must first know what products and uses are they.
For example, thin-walled products should use High-Speed Injection Molding Machines, because the plastic will quickly cool in the mold and lose its fluidity, resulting in the insufficient filling. Or if you have dual-color or dual-material injection requirements (such as automotive lighting), you can choose Dual Injection Molding Machines.
If the product is made of PVC or PET, the configuration of the injection molding machine also needs to be adjusted. Both PVC and PET injections need to be equipped with special screws, and the PVC Rigid Injection Molding Machine is designed with width extended shield. The PET Preform Injection Molding Machine needs to be equipped with a dehumidifying dryer and mold dehumidifier to keep plastic dry.
Huarong is one of Taiwan's few injection molding machine manufacturers that covers the complete models. We can customize it for you if you have any special injection needs, and we try our best to meet all your injection needs.

2. Size and weight determine the tonnage of the machine

When the product size and weight are larger, the tonnage of the machine will increase. As the size of the accommodating mold mentioned above, the larger the product is, the larger the mold will be, and the clamping force will also need to be increased. Otherwise, it may cause product flash. So it is best to provide product drawing with size or product samples, and the injection molding machine manufacturer can better assist you in choosing a suitable machine.
If your products are long and large, such as chairs, barrels, etc., you can choose Two-platen injection molding machine with a longer opening stroke.

3. Plastics determine whether to choose Bulk Molding Compound Injection Molding Machine

If the product needs to be resistant to high temperature, then you may choose to use BMC bulk molding compound as the plastic, which is often used in electric motors, electronic, transportation, and construction industries. 
If this kind of plastic is selected, then the model needs to choose Bulk Molding Compound Injection Molding Mmachine. Contrary to the cooling and solidification of general injection molding machines, this model is heated to solidify the product, and the special screw is anti-corrosion, wearing proof. Suitable for the production of anti-corrosion, high-temperature resistance, and insulation products.


When choosing an injection molding machine, in addition to the above points, many details still need to be considered. An injection molding machine may operate nearly 24 hours a day. Therefore, if you choose an unsuitable injection molding machine, it will cause unnecessary waste and loss. Choosing the right injection molding machine means choosing the right industrial equipment to help you improve your competition.

Trust comes from sincere communication. To meet all the injection molding needs of customers and become a good partner of industrial alliances that customers are willing to entrust, in addition to providing you with complete advice and consultation, Huarong continues to expand its product line and becomes one of the few injection molding machine manufacturers in Taiwan with the broadest range of models. Huarong provides horizontal, vertical, and multi-shot injection molding machines and establishes an automation and intelligence department under the wave of Industry 4.0 to assist customers in planning fully automated production and building a smart factory.

Huarong's consistent core value is "Quality-Innovation & Industry-Alliance."


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