Cause analysis and elimination of flow mark in die casting

In the die casting industry, we all know that die casting surface defects are common, and there are many types of defects, and the names of different places are also different, such as flow marks, some called stripes. What is puzzling is how the flow marks of die castings are produced. Is there any solution?

1、 What are flow marks in die castings?

The main feature of flow mark in die casting is that the surface of casting presents smooth local settlement pattern consistent with the flow direction of liquid metal. The flow mark defect has no development direction and can be removed by polishing method.

How to produce flow marks on die castings? Die casting manufacturers analyze the causes of flow marks

① Traces left by two metal streams filling the cavity asynchronously.

② The mold temperature is low, such as zinc alloy mold temperature < 150 ℃, aluminum alloy mold temperature < 180 ℃, easy to produce such defects.

③ The filling speed is too fast.

④ Too much paint is used.

How to eliminate flow mark defect of die casting parts? Heyi's solution:

① Adjust the cross-sectional area or position of the gate.

② Adjust mold temperature and increase overflow groove.

③ Adjust the filling speed and change the flow pattern of the filling cavity.

④ The coating shall be thin and uniform.

2、 Prospect analysis of die casting industry standardization

Energy saving and emission reduction has become the main theme of today's society. Compared with the traditional die-casting machine, energy-saving die-casting machine not only has excellent performance in energy consumption, function, response speed and control accuracy, but also can save capital for enterprises. Therefore, die casting machine manufacturers and users are widely welcomed. This means that China's die casting industry will usher in a great leap forward.

According to "2015-2020 China's die casting industry market outlook and investment strategic planning analysis report", in recent years, China's die casting industry has continued to develop, with the improvement of technical level and core competitiveness, domestic die-casting machine has gradually integrated into the world market. The development of die casting industry, on the one hand, provides a bigger stage for the development of die casting machine in China, on the other hand, it also puts forward higher requirements for the continuous promotion of die casting machine.

As is known to all, the following processes are involved: die-casting, injection molding, injection molding, injection molding and injection molding. In each stage, hydraulic oil is pumped from the oil pump motor to each cylinder to push the transmission mechanism to complete a series of actions. The matching of pressure and flow is different in each stage. In one working cycle of die casting machine, the parts with large load are high-pressure mold locking and injection stage, and the load of other links is small, so the load is almost zero in the cooling process. In the hydraulic system of constant displacement pump, the surplus hydraulic oil flows back through the safety valve. This process is called high pressure closure, and its energy loss is generally about 50%.