* Rib
1. The rational application of rib can increase product rigidity and reduce deformation.
2. Thickness of rib ≤（0.5～0.7）product stock thickness to avoid pinsink mark on surface.
3. Bosseyed angle of rib＞1.5° to avoid bad ejection.
* Fillet
1. Too small fillet causes concentrated product stress and product cracking.
2. Too small fillet causes concentrated mold cavity stress and product cracking.
3. Setting reasonable fillet can improve processing technic of mold, like cavity can be cut millinged by R cutter directly to avoid inefficient EDM.
4. Different fillet may cause the move of parting line; fillet and under cut should be chosen according to practical situation.
* Aperture
1. The shape of aperture should be as simple as possible and generally be round.
2. When the axial direction of aperture is in line with mold opening direction, core-pulling can be avoided.
3. When the L/D ratio of aperture ＞ 2, ejection angle should be set. At this point, the diameter of aperture shall be calculated according to the size of minor diameter (maximum physical size).
4. Generally the L/D ratio of blind hole ≤ 4 to avoid needle is bended.
5. Generally the distance between aperture and product edge ＞ the aperture diameter.
The article comes from China injection mold manufacturer - Mold Best Assurance Company Limited, website is www.mbamoldanddesign.com
