| Gate Type | Best For | Removal Method | Pros | Cons | | :--- | :--- | :--- | :--- | :--- | | | Flat parts | Manual trim | Low cost, easy to modify | Leaves a vestige | | Submarine (Tunnel) | Automatic tools | Shears during ejection | No manual trimming | High shear stress | | Hot Tip (Valve) | High volume, aesthetics | Automatic (gateless) | No sprue, clean vestige | Expensive tooling | | Fan Gate | Large thin parts | Manual | Reduces jetting | Takes up edge space |
Where two melt fronts meet after flowing around a hole or insert. Higher mold temperatures, increased injection speeds, and proper gate placement minimize weld lines.
If thickness variations are unavoidable, use a gradual transition with a 3:1 slope to maintain smooth material flow. Draft Angles injection mold design guide
: The outer diameter should be roughly double the screw diameter.
A standard focuses on Design for Manufacturability (DFM) to ensure plastic parts can be produced efficiently without defects like warping or sink marks. The process involves injecting molten plastic into a metal mold, where it cools and solidifies before being ejected. Successful design relies on a "molding trinity" of principles: uniform wall thickness , adequate draft angles , and the elimination of undercuts . Core Design Principles Injection Molding Design Guide | Downloadable from Fictiv | Gate Type | Best For | Removal
Design ribs to be 40% to 60% of the nominal wall thickness to prevent sink marks on the cosmetic flip side.
Increase draft to 3 to 5 degrees or more for textured surfaces to prevent scuffing. Radii and Fillets Draft Angles : The outer diameter should be
INCORRECT CORRECT | | | / \ | | Thick | | / Thin \ | | Wall | |/ Wall \| +-------------+ +-------------+ (Causes Sink) (Uniform Wall) Uniform Wall Thickness
