Weld line on molded parts in injection molding process

We often find the weld line in injection molding process. weld line is one of

the most serious defects in injection molding products, it is not only affects the appearance quality of the products, but also impact on the product strength, and the weld line is difficult to handle after the painting or any other processing,so it is necessary to shorten the length of the weld line.

 

As the contingency interface displayed on the surface when the molten resin fill in,resulting in reduction in strength and affects the appearance, in order to not produce the weld line in where need to bear external forces or the eye-catching parts，we should move the weld line to the side where does not affect the appearance and the intensity of use, the CAE software can predict the location of the weld line, by changing the product design or gate design during the design of the mold, make the weld line move to the position where the strength and quality of appearance is not important,weld lines often occur where the confluence of the molten resin in the injection molding, by Improving the injection pressure, melt temperature and the temperature of the cavity can help overcome the melt flow resistance of the system of injection molding, It is effectively promote the injection holding pressure transfer to the front of the material flow. It will confluence the material flow integration at higher pressure, it will increase the density in the position of welding line and the intensity also increased,therefore it is better for melt fusion.

 

It should be noted that, due to the requirements of the product structure,the weld lines / fusion marks is inevitable, but by controling the temperature to meet the two shares of the melt (no more than 10-C), improve the conditions such as injection pressure and cavity temperature to Improve the strength of the position in melt fusion.