Car Bumper Injection Molding Machine

With the rapid development of automobile industry, plastic parts are more and more widely used in automobiles. The application of automobile plastic parts has significant effects on reducing automobile quality, saving fuel, promoting environmental protection and recyclability. The car bumper mainly adopts injection molding. ZOWEITE® GF2300LB machine is specially designed for bumper.

What are the common injection defects in injection molding automobile bumper?

Tiger skin pattern

Tiger skin pattern is easy to occur on parts with thin wall thickness and large process. Because the more toughening systems in the material, the more likely tiger skin striation is to occur. Tiger skin striation is rarely found in materials with poor toughness, such as reinforced materials, non toughened nylon, PBT and other materials. EPDM is added to PP material used in automotive injection molding parts because of its high impact performance. Poe and other toughening components are very prone to tiger skin defects.

How to improve tiger skin pattern?

In the mold design of car bumper injection molding machine, increasing the diameter of runner and expanding the thickness and width of gate are effective measures to eliminate tiger skin pattern. The gate thickness is preferably 0.7-0.8 times the wall thickness. This will reduce the pressure loss of the melt in the runner and gate and reduce the die expansion effect when entering the cavity.

In the injection molding process of car bumper injection molding machine, increasing melt temperature and mold temperature and adjusting injection speed are conducive to eliminating tiger skin lines. In general, the use of lower shooting speed is conducive to the elimination of tiger skin lines, because the melt flow is more stable at low speed.

Material flower

The flower makeup cold material near the car bumper will not only affect the apparent quality of the parts, but also affect their mechanical properties.

There may be material flowers in the car bumper because the cold channel on the die has no cold material well and is directly connected to the part. In terms of the molding process of the car bumper injection molding machine, it may be that the glue sealing of the needle valve gate is not strict, there is residual cold material on the gate, and the air pressure for sealing the needle valve is very low, which can not play the role of glue sealing. After using air pressure pressurization to increase the needle sealing air pressure, the cold material disappears after the hot gate no longer leaks.

Because of the need for cooling around the nozzle of the ZOWEITE® car bumper injection molding machine, there is sometimes a cooling circuit, which further increases the possibility that the temperature at the front end of the nozzle is too low. The temperature at the front end of the nozzle is low, resulting in a small part of cold material at the front end, especially when the sealing needle and rubber are not tight, the melt overflows, which is easier to form cold material. Therefore, when the hot runner nozzle turns to the cold runner, it is recommended to set a cold material well on the cold runner.

Peeling

On the surface between automobile bumpers, the defective rate is low, and it is difficult to find peeling defects, but this defect seriously affects the appearance quality of parts.

The peeling of car bumper may be caused by cold material in the molding process of car bumper injection molding machine, and the cold material rushing into the cavity may cause delamination peeling. The source of cold material may be too low material temperature, too low nozzle temperature, no cold well set in the flow channel or insufficient length of cold well, too low hot runner temperature, too low mold temperature, etc.

swelling

The bulge of the car bumper may be that the mold of the car bumper injection molding machine does not set an exhaust slot at the bulge, so it is difficult to exhaust the gas during the injection molding process, because it is necessary to add an exhaust slot on the mold.

ZOWEITE® injection molding machine can provide turnkey engineering for novice and inexperienced customers, including injection molding machine, mold, auxiliary equipment and drawings. We will test the production line in the factory and deliver the machine to the customer's factory after ensuring that we can produce quality products.