The proportion of plastic materials in life is becoming higher and higher, and the demand for its quality is becoming more and more high. As an important means of production, the injection molding of vertical injection molding machine is more and more urgent to improve the technology. However, there are many factors affecting the injection molding products, but the injection molding process conditions are important factors.

The traditional mold design and process parameter settings lack scientific basis, the production cycle is long, the cost is high, and the quality is also difficult to guarantee. The molding process of the vertical injection molding machine is simulated. The problems in the design can be found before the mold is made. The design of the mould and the setting of the process parameters can be set up on the basis of the scientific analysis, which can shorten the production cycle and improve the quality of the products.

With the improvement of product quality requirements, prediction of forming process has become an indispensable part of design. Therefore, it is of great significance to establish a mathematical model of the flow and heat transfer of the melt in the cavity of a vertical injection molding machine, and to simulate the process by numerical simulation. The process parameters directly determine the flow state of the melt in the mold cavity, and have the most direct and far-reaching influence on the quality of the products. Therefore, it is an effective way to improve the quality of the plastic products by finding the optimal process conditions and controlling the process of the molding process.

In the molding process, the precise vertical injection molding machine, the reasonable mold design and the excellent material performance can only be reflected under the reasonable molding process settings. On the other hand, the defects of vertical injection molding machine, mold design and material performance can sometimes be compensated by suitable molding process settings.

It can be seen that the injection molding process of vertical injection molding machine plays a key role in the quality of products. 

Conditions and influence of injection molding process

1. injection pressure

The injection pressure of a vertical injection molding machine refers to the pressure on the top of the screw or the plunger on the plastic melt during the injection process.

Its function makes the plastic melt fill the cavity at a certain speed. After the cavity is filled with melt, the injection pressure acts as compaction.

As a result, the plastic parts are compact, and the shrinkage caused by cooling is also fed, so that the plastic parts can maintain accurate shape and get the required performance.

The injection pressure is mainly determined by the type of plastic, the type of the vertical injection molding machine, the temperature and structure of the mould, the wall thickness of the plastic parts, and the size and structure of the pouring system have a great influence on the injection pressure.

2. pressure retaining pressure

Injection pressure is also called pressure protection pressure.

In actual production, the holding pressure should be equal to or less than the pressure when injected. When the pressure is equal to the pressure at the time of injection, the shrinkage of the plastic part can be reduced, and the stability of the plastic part and the mechanical properties of the plastic part can be guaranteed.

However, it is often accompanied by the increase of residual stress at the time of demoulding, which causes the plastic parts to die hard, make the plastic parts easily deformed, surface scratching and so on, and easily cause the plastic parts to produce the flown edge and influence the apparent quality. Therefore, when choosing packing pressure, we need to consider various aspects and choose carefully

3. plasticizing pressure

The plasticizing pressure of the vertical injection molding machine refers to the pressure on the top of the screw when the screw is backward. Its influence on injection molding is mainly reflected in the plasticizing effect and plasticizing ability of the injection machine. However, at the same time, when the back pressure is increased, high plasticizing pressure reduces the plasticizing amount and may cause insufficient measurement. On the other hand, the shear stress is too high, which may degrade the material, produce bubbles or burn, and affect the quality of the plastic parts.