Solutions to common defects in TPE injection molding

The appearance of various irregular lines on the surface of TPE products, which affect the appearance quality of products, must be common. Various texture defects on the surface of TPE products can be divided into the following two situations according to their causes:

1. Injection flow mark

Injection flow mark is the trace of molten metal flow, which takes the gate as the center and presents stripe shape. Flow mark is the boundary between the material injected into the mold cavity and the material flowing after it. In order to prevent the formation of injection streaks, it is necessary to increase the injection temperature, improve the fluidity and apintejinust the injection speed.

Solution: reduce the injection speed properly. In addition, if the molding temperature is too high, the material will decompose and produce gas, which will also lead to the formation of flow marks. In addition, the molding temperature should be controlled. If the material contains moisture, when the water is formed at high temperature, the water evaporates to form gas, which also leads to the appearance of flow marks, and if the molding temperature is low, no tone pockmarks are formed.

2. Material flow mark

The formation of flow marks is independent of gas. It is mainly affected by material fluidity, plasticization degree, injection mold temperature and gate temperature. The structure of injection mold and runner affects the fluidity of materials. If the melt filling is not completed quickly, the melt temperature and flow rate will decrease, and flow marks will be formed on the surface of the product;

Solution: if the injection mold temperature and gate temperature are too low, the friction between the melt and the injection mold surface will increase, resulting in material flow marks;

The injection mold temperature and mold gate temperature should be increased properly. The material plasticization is not enough, melting is not good, easy to cause obvious material flow mark on the product surface; solution: correctly increase the injection temperature and screw speed to enhance the plasticization.

3. Sticky phenomenon

Compared with resin, the surface of soft TPE injection molding products is more prone to sticky phenomenon.

Solution: at this time, we can reduce the molding temperature, low shear, and use nitrogen to purify the internal part of the hydraulic cylinder block of the molding machine to solve the problem of sticking on the surface of the product. In addition, when the molding machine is suspended, the rubber is placed in the mold cavity of the molding machine in a molten state for a long time, and sometimes it will become sticky due to thermal aging. In addition, the products used in high temperature are easy to appear sticky phenomenon. Therefore, the selection and dosage of stabilizers and softeners should be selected reasonably.

About PTJMould Industrial Company Limited

PTJmould is a China mold maker of plastic molds- injection mold, die casting moulds, plastic blow molding, rotational molding, medical plastic injection molding, two shot plastic injection molding, insert molding, overmolding, metal injection molding, micro injection molding, powder injection molding, ceramic injection molding, liquid injection molding, husky injection molding, household mold, casting mold, die mold tool, custom molds, china moulds, rapid prototyping tooling, plastic prototyping tooling, punch press tooling, die and tooling for mobile/ cell phone parts, automotive parts, vacuum cleaners, rechargeable tools, telephones, copiers, computers, multimedia speakers, and many other electronic products and household appliances. And also a plastic product manufacturer, mold manufacturer China– plastic parts, plastic water tank, plastic balls, plastic containers, plastic buckle, plastic anchor, plastic hanger, plastic spoon, plastic pipe fitting, plastic tumble, plastic tableware, plastic cups, plastic bottles, plastic tray, plastic cosmetic container, plastic case, plastic food container, plastic chairs, plastic caps, plastic cap closure, plastic tubes, plastic water pipes, plastic knobs, plastic tubing, plastic utility boxes, plastic racks and so on.