Five common errors in injection molded part design

Do not add draft angle
A draft angle is required in the mold to release plastic components from the mold. Plastic usually shrinks towards the center of the part. Without a draft angle, the part will stick to the mold and cannot be demolded correctly. If possible, design a 1 ° draft angle on each side, and any draft angle will help release the part.
Uneven wall thickness
Different wall cross-sections are common in part design and can lead to unexpected part characteristics during molding. Plastic is difficult to flow and transition between uneven wall thicknesses. Thick walled sections may experience different shrinkage, which may cause deformation of the parts. Try to make the wall thickness at least thicker in the gate area and thinner at the end of filling. Strive for a wall thickness of 0.080-0.120 inches and utilize rib and gusset plate features in part design.
Unnecessary depression
Due to the complexity of today's part design, dents are often overlooked in the design process. The depression in the mold needs to be treated before demolding the part, otherwise it will damage the part. In mold processing, there are many methods to solve the problem of dents, such as through core design, sliders, cores, or elevators. A simple rule for design: concave+complex mold=higher cost.
Selecting the wrong material
Material selection is another common mistake I see. The selection of materials should be based on the position of the parts. Parts that will live outdoors should have UV stabilizers to prevent cracking. The parts that bear the load should be reinforced with fillers such as fiberglass. Parts with bearing surfaces should have additives such as lubricants.
Excluding fillet radius
In part design, the fillet radius is often ignored. The rounded radius strengthens the area, making it more robust in the long run. The radius reduces stress concentration and fracture in plastic parts. It also makes the parts look beautiful and reduces the risk of injury during handling.