Case Study: Fall-Arrest System Pulley

Process: Metal Injection Molding (MIM)

Material: MIM-17-4 PH stainless steel

Density: 7.67 g/cm³

Hardness: 35-40 HRC

Weight: 62 g

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End Use and Function

The pulley regulates rope movement and provides automatic braking and locking during a fall. Rapid descent or sudden loading triggers immediate engagement for height-related construction, maintenance, and rescue applications.

Fabrication

The pulley is produced in a two-cavity hot-runner mold with multiple slides that form the spike geometry and mounting features. Carefully positioned gates and vents promote complete filling, while special sintering setters and controlled heating maintain roundness and prevent thin-wall distortion. Heat treatment establishes the required hardness.

Results

MIM delivers accurate, repeatable geometry, a high-quality surface finish, reduced porosity, and minimal machining. The resulting pulley provides reliable braking control and durability while improving material utilization and reducing cost compared with machined or cast alternatives.