During the injection molding process, due to the plastic uneven cooling in the mold cavity and uneven shrinkage and molded parts design unreasonable, likely caused by a variety of defective products:
Microprinting, weld mark, porosity, deformation, galling, top injury, flash.
To obtain high-quality plastic products, we must fully consider the structure of the product design process, the following main structural features combined analysis of injection molded plastic products avoid injection defects.
1 mold parting line direction
Each injection product design at the beginning of the first to determine the direction and the mold parting lines, in order to ensure as much as possible to reduce the pulling mechanism and eliminate the effect of the parting line of appearance.
1.1 mold after determining the direction, product ribs, snap, projections and other structures designed to be consistent with possible mold direction, in order to avoid reducing core pulling patchwork line, extend die life.
1.2 Example: bumper mold direction is generally the vehicle coordinate χ direction, if a model designed to χ axis direction is inconsistent, it must indicate their angle in the product drawing.
1.3 mold direction is determined, choose the appropriate parting lines to improve the appearance and performance. 2 stripping slope
A proper draft is to avoid product nap. Smooth surface stripping slope greater than 0.5 degrees, one degree higher than the surface of fine sticks, sticks rough surface is greater than 1.5 degrees.
2 proper draft is to avoid products top injury.
3 Deep cavity design requires less than the slope of the outer surface of the inner surface of the slope, to ensure that when the injection mold core without deviation, to obtain a uniform product thickness, and the opening portion of the product to ensure the strength of the material density.
3 Product thickness
3.1 All kinds of plastic have a certain thickness range, generally 0.5 ~ 4mm, when the thickness of more than 4mm, will cause the cooling time is too long, resulting in microprinting and other issues, should consider changing the product mix.
3.2 microprinting surface can cause uneven thickness. 3.3 will cause uneven thickness and weld porosity marks.
4.1 to strengthen the rational use of ribs, increase product rigidity and reduce distortion.
4.2 stiffener product wall thickness must be less than 1/3, otherwise the surface microprinting.