How to solve the problem of flow marks on the surface of injection molded products?

Flow mark is a common appearance defect of injection molded products. It will have a great impact on production, so how to solve it? Now let’s talk about how to solve the problem of flow marks on the surface of injection molded products?

Fault analysis and troubleshooting
1. The poor flow of molten material leads to the annual ring shaped ripple flow mark centered on the gate on the surface of plastic parts. It can be adopted to increase the temperature of the mold and nozzle, increase the injection rate and filling speed, and increase the injection pressure and pressure maintaining and boosting time. A heater can also be set at the gate to increase the local temperature at the gate. The gate and runner area can also be appropriately expanded, and the gate and runner section is preferably circular, which can obtain the best mold filling. However, if the gate is set in the weak area of the plastic part, the square section shall be adopted. In addition, a large cold hole shall be set at the bottom of the injection port and the end of the diversion channel. The greater the influence of the material temperature on the flow performance of the molten material, the more attention shall be paid to the size of the cold hole. The position of the cold hole must be set at the end of the molten material along the flow direction of the injection port.
2. The unsmooth flow of molten material in the flow channel leads to spiral wave flow marks on the surface of plastic parts. When the molten material flows from the narrow section of the flow channel into the mold cavity with large section or the mold flow channel is narrow and the finish is very poor, the material flow is easy to form turbulence, resulting in the formation of spiral wave flow on the surface of the plastic part. In this regard, the injection speed can be appropriately reduced or the injection speed can be controlled slowly, quickly and slowly. The gate of the mold shall be set at the thick wall part or directly at the wall side. The gate shall preferably be in the form of handle, fan or diaphragm. The runner and gate section can also be appropriately expanded to reduce the material flow resistance.
3. Volatile gas causes cloud like ripple flow marks on the surface of plastic parts. When ABS or other copolymer resin raw materials are used, if the processing temperature is high, the volatile gas produced by the resin and lubricant will cause cloud like ripple flow marks on the surface of plastic parts. In this regard, it is necessary to properly reduce the temperature of the mold and barrel, improve the exhaust conditions of the mold, reduce the material temperature and mold filling rate, appropriately expand the gate section, and consider changing the lubricant variety or reducing its dosage.
The above is the fault analysis and troubleshooting methods listed on how to solve the flow marks on the surface of injection molded products. I hope it will bring you harvest.



About Huizhou Dj Molding Co., Ltd

Dj Mold 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.

Person: James Yuan
Company: Huizhou Dj Molding Company Limited
Add:  LongGang Village,LongXi Town,BoLuo County,HuiZhou City,GuangDong Province, China
Tel: 86-752-6682869
Email: [email protected]


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