A Comprehensive Analysis of Injection Molding Machine Screw Temperature Control from Heater to Cooling System

The control of screw temperature is crucial in the injection molding process. It not only directly affects the melting state, fluidity, and physical properties of plastic materials, but also relates to production efficiency, energy consumption, and stable operation of equipment

The importance of screw temperature control:

1、 Affects the melting state of plastics

The temperature of the screw directly determines the degree of melting and flowability of the plastic. When the temperature is too low, the plastic is not easily melted, which can lead to insufficient plastic filling during the injection molding process, resulting in incomplete or defective injection molded parts. On the contrary, if the temperature is too high, the plastic will melt excessively or even degrade, which will not only change the physical and chemical properties of the plastic, but also affect the performance of the final product.

2、 Affects product quality

Improper control of screw temperature can directly lead to various quality problems in injection molded parts. For example, low temperature may cause shrinkage of injection molded parts, that is, the surface of injection molded parts may appear concave or uneven; If the temperature is too high, it may cause the injection molded parts to burn, that is, the plastic degrades at high temperatures, producing a burnt smell and burnt spots. In addition, improper temperature control may also lead to defects such as bubbles and cracks in injection molded parts, seriously affecting the appearance and performance of the product.

3、 Affects production efficiency

Inaccurate temperature control of the screw will directly affect the length of the injection molding cycle. If the temperature is too low, the plastic is not easily melted and the injection molding process will be prolonged; If the temperature is too high, the plastic will melt excessively, causing the injection molding machine to need more time to cool and solidify the injection molded parts. This will not only reduce production efficiency, but also increase energy consumption and production costs. Therefore, precise control of screw temperature is of great significance for improving production efficiency and reducing costs.

Application of Heater and Cooling System in Injection Molding Machine Screw Temperature Control

1、 Heater

The main function of the heater is to increase the temperature of the screw and barrel, ensuring that the plastic can fully melt during the injection molding process. The types and working principles of heaters are as follows:

Type:
Resistance heating: This is the most common heating method, which generates heat through an electric current passing through a resistance wire, and then heats the screw and barrel.
Electromagnetic induction heating: Using the principle of electromagnetic induction, eddy currents are generated in the screw and barrel, and the heat generated by the eddy currents is used for heating.
working principle:
Resistance heating: When current passes through a resistance wire, the wire heats up and transfers the heat to the screw and barrel. By controlling the magnitude and duration of the current, the heating power can be adjusted to control the temperature.
Electromagnetic induction heating: When an alternating current passes through a coil, an alternating magnetic field is generated in the screw and barrel, which in turn generates eddy currents inside the metal. Eddy currents interact with the resistance inside the metal, generating heat that heats the screw and barrel.
2、 Cooling system

The main function of the cooling system is to reduce the temperature of the screw and barrel, preventing plastic from overheating and degrading. The types and working principles of cooling systems are as follows:

Type:
Water cooling: Reduce the temperature of the screw and barrel through a circulating water system. Water cooling systems typically include components such as water tanks, water pumps, water pipes, and radiators.
Oil cooling: using circulating oil to reduce temperature. Oil cooling systems typically include components such as oil tanks, oil pumps, oil pipes, and radiators.
working principle:
Water cooling: Cooling water enters the cooling channels of the screw and material cylinder through water pipes, absorbs heat, and then dissipates it into the air through a radiator. By adjusting the flow rate and temperature of the cooling water, the cooling speed of the screw and barrel can be controlled.
Oil cooling: Cooling oil enters the cooling channels of the screw and barrel through oil pipes, and also absorbs heat before dissipating it into the air through a radiator. The control method of the oil cooling system is similar to that of the water cooling system.
3、 Collaborative operation of heater and cooling system

During the injection molding process, the heater and cooling system need to work together to ensure that the temperature of the screw and barrel remains within the ideal range. When the plastic needs to melt, the heater will increase the temperature of the screw and barrel; When plastic needs to be cooled, the cooling system will lower the temperature of the screw and barrel. By precisely controlling the power and time of heating and cooling, precise control of screw temperature can be achieved.