There is no fixed standard for the thickness of injection - molded parts, which generally ranges from 0.5mm to 6mm. However, this value is affected by many factors, as detailed below:
Different plastic materials have different flowability, shrinkage rates, and cooling rates. Materials with good flowability, such as PP or PE, can support larger wall thicknesses; while materials with poor flowability, like PC or POM, are more suitable for thinner wall thicknesses. For example, the common wall thickness range of ABS products is generally 1.5 - 5.0mm, and that of PP products is 0.6 - 3.5mm.
When the product structure is complex, with many reinforcing ribs, holes, or curved surfaces, an excessively large wall thickness is prone to causing uneven cooling, leading to problems such as shrinkage, deformation, or internal stress. For example, the wall thickness of a plastic shell with many reinforcing ribs is usually not suitable to exceed 4mm, otherwise, it is difficult to ensure product quality.
The design of the mold cooling system must ensure uniform cooling of the product to avoid heat accumulation caused by excessive wall thickness. If the mold cooling system is not reasonably designed, it is difficult to form products with large wall thicknesses even if the material and product structure permit.
The control of injection pressure, temperature, and time will affect the forming effect of wall thickness. Too large a wall thickness may require higher injection pressure and longer cooling time, increasing production costs and the forming cycle. For example, the cooling time of some large thick - walled products may be extended from tens of seconds for ordinary products to several minutes or even longer.
For most ordinary plastic products, the wall thickness is commonly designed between 1.5mm and 3mm. If a product requires a larger wall thickness, special processes such as gas - assisted injection molding or structural foam molding can be considered to reduce material usage and forming defects.
