Trapped gas burns plastic. Sam scribed 0.03mm deep vents along the parting line. Air escaped; parts filled.
: Internal radii should be at least 50% of the wall thickness. 2. Strengthening Features
Use "coring" to remove material from thick sections, maintaining a uniform nominal wall while keeping the part's structural integrity. 2. Draft Angles injection mold design guide
Pins push. Sleeves surround. Blades lift. Never just one lonely pin in the middle—that's how parts warp.
| Material Family | Shrinkage (%) | Flowability | Key Design Considerations | |----------------|---------------|-------------|---------------------------| | | 0.4 - 0.7 | Medium | High toughness, good aesthetics, susceptible to stress cracking | | Semi-Crystalline (Nylon, POM, PP) | 1.5 - 3.0 | High (when melted) | Requires uniform walls to avoid warp, high shrinkage | | High Flow (PS, PE) | 0.3 - 0.8 | Excellent | Ideal for thin walls, but may flash easily | | Filled Materials (Glass-filled Nylon) | 0.1 - 0.5 | Poor | Abrasive to mold, anisotropic shrinkage, requires hardened steel | Trapped gas burns plastic
: Vertical walls must have a slight taper (draft) to allow the part to release from the mold. 1 raised to the composed with power 2 raised to the composed with power for most parts. 0.5 raised to the composed with power is necessary for vertical faces. Radii and Fillets
Injection Mold Specifications & Plastic Mold Design Guideline : Internal radii should be at least 50%
: Ribs should be 40–60% of the thickness of the adjacent wall to prevent sink marks on the opposite side.
Edge gate for flat parts? Submarine gate for hidden beauty? He chose a fan gate to fill that long, shallow lid evenly. No more hesitation lines.