CNC Turning Parts of Ejector Sleeve Pin Set

Customer Pain Point:
The sliding fit issue between the ejector sleeve and the ejector pin，particularly the stuck movement of the precision customized ejector pins due to high friction resistance..

Optimized Solutions:
(1) Dimensional Accuracy and Fit Clearance
Problem: Excessive clearance (wobbling) or insufficient clearance (stuck).
Improvement Measures: Use high-hardness cutting tools to reduce wear and maintain precision, ensuring the fit clearance between the inner hole of the ejector sleeve and the outer diameter of the ejector pin is 0.01–0.02mm.
(2) Surface Roughness Optimization
Problem: Tool marks and burrs increase friction resistance.
Improvement Measures: Grind the inner hole of the ejector sleeve and the surface of the of the ejector pin to achieve a surface roughness of Ra ≤ 0.8μm.
(3) Material and Hardness Matching
Problem: Ejector pins with HRC60 are too hard, leading to brittle breakage.
Improvement Measures:
Ejector pin material: SKD61, with heat treatment hardness of 52–54 HRC.
Ejector Sleeve material: Hardness should be slightly higher than that of the ejector pin (e.g., SKD11, 56–58 HRC) to avoid wear on the inner wall of the sleeve.
The hardness of the ejector sleeve is greater than that of the ejector pin, which can avoid the strain caused by “soft biting hard” .

Results
Ultimately, these measures helped the customer extend the mold life by 30% and improve production efficiency by 15%, thereby reducing costs and strengthening market competitiveness.