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Ejector Pin Design Guide

Proper ejection system design for injection molds

Types of Ejector Pins

Type	Application	Standard
Standard Flat Ejector Pin	General purpose	JIS, HASCO, DME
Step Ejector Pin	For thin wall sections	JIS, DME
Blade Ejector	For ribs and thin features	Custom
Sleeve Ejector	Around core pins	JIS, HASCO

Design Guidelines

Place pins on ribs, bosses, and deep walls (areas of highest shrinkage force)
Minimum draft angle of 0.5-1 degree on ejection surface
Pin diameter should be as large as possible to reduce stress
Ejector stroke = part depth + 5-10 mm minimum clearance
Use at least 4 pins for balanced ejection force

Common Problems

Pin marks on part surface - reduce pin diameter or use stepped pins
Pin sticking - insufficient clearance or galling
Broken pins - inadequate diameter or improper material
Incomplete ejection - insufficient stroke or unbalanced force