The reason and solution for surface roughness

Surface roughness means there is a lack of precision in the surface of a molded part, or an inconsistent level of precision all over the surface, e.g. some areas are glossier than the rest. The main reasons for surface roughness might lie in the injection molding machine, the mold, the process or the material.


(1)Injection Molding Machine

①Insufficient material supply;

②Material barrel is not thoroughly cleaned when changing material;

③Check for cold melt leakage at the nozzle;



①The gate is too small, or the runner is too thin – increase the gate size, or adopt the film gate;

②The surface of the mold cavity is rough – polish the cavity surface and check if there’s any leakage;

③Poor venting – add vents in the location with poor glossiness for an improvement;

④Increase the size of or add a cold slug well to collect the cold material;

⑤Mold temperature is too low – raise mold temperature;

⑥Might be affected by mold release agents – stop the application of mold release agents;


(3) The Injection Molding Process

①Increase melt temperature (check whether the heating zone of the material barrel is in disorder – non-uniform temperature, local temperature too high or too low, etc.)

②Increase nozzle temperature;

③Over shear caused by over-speed injection – lower injection speed appropriately;

④Increase injection pressure;

⑤Increase material injection time;


(4) Raw Materials

①Raw material is not dried;

②Too much recycled materials are added, or repeatedly recycled materials are decomposed;

③Excessive application of mold release agents.

About JasonMould Industrial Company Limited

Jasonmould 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: JasonMould Industrial Company Limited
Add:  LongGang Village,LongXi Town,BoLuo County,HuiZhou City,GuangDong Province, China
Tel: 86-752-6682869
Email: [email protected]


Share this post