Avoid Sink Marks: Optimal Wall Thickness for Injection Molding

Uniform wall thickness is critical for injection molded parts. Thick sections cool slower and shrink more, causing sink marks, warpage, and longer cycle times. Aim for consistent thickness across the part.

Typical wall thicknesses range from 1.5 mm to 4 mm for most engineering plastics. For amorphous materials like ABS, thinner walls are feasible, while crystalline materials like nylon may need thicker sections to ensure proper flow and packing.

Always transition gradually between thicknesses. Use radii at corners to reduce stress concentrations and improve flow. A good rule of thumb is to keep thickness changes below 50% of the nominal wall, with a smooth taper over at least three times the thickness difference.

Consider the flow length to wall thickness ratio. For long, thin parts, increase wall thickness or adjust material selection. Remember that thicker walls increase cooling time exponentially, so optimize for both function and manufacturing efficiency.

#GDandT# #Fasteners# #SealDesign#