1. For blind holes, if D<5mm, then h≤2D.
2. For blind holes, if D>5mm, then h≥3D.
3. For through holes, if D<5mm, then h≤4D.
4. For through holes, if D>5mm, then h≤6D.
a) The bottom height of blind holes should be at least 0.2x the blind hole diameter, i.e.: h≥0.2D.
b) Consider strengthening the bottom of blind holes as figure b) shows.
The dimensions for hole space, and the space between hole and part edge should follow s ≥ 1.5t or 1.5D.
The welding marks are highlighted with blue arrows.
a) The original hole design is prone to deformation.
b) Add the boss to hole edge to strengthen the part.
a) The hole direction is perpendicular to the flow direction.
b) The hole direction is consistent with the flow direction.
The round holes design is recommended, as it is easy to process, leading to low mold costs and even better ventilation.