Designing a Tool System for Lowering Friction during the Ejection of In-Die Sintered Micro Gears

Area of Science:

• Materials Science
• Manufacturing Engineering
• Mechanical Engineering

Background:

• Micro-forging technologies are continuously evolving, focusing on process, material, and tool design.
• Field Assisted Sintering Technique (FAST) enables near-net-shape manufacturing in closed-die systems.
• Part quality in FAST is often compromised by ejection friction due to powder radial expansion.

Purpose of the Study:

• To develop and evaluate a pre-stressed tool system for manufacturing micro gears from aluminum.
• To compare the performance of a pre-stressed tool system against a non-pre-stressed system.
• To assess the impact of pre-stressing on ejection force and part fidelity.

Main Methods:

• Development of a pre-stressed tool system for micro gear production.
• Utilizing hot isostatic pressing (HIP) sintering with varied process parameters.
• Comparative analysis based on measured ejection force and multi-scale part characterization (optical microscopy, computed tomography).

Main Results:

• The pre-stressed tool system demonstrated a 40% reduction in gear porosity.
• Dimensional fidelity of the micro gears was improved by over 75% with the pre-stressed system.
• Ejection force was measured to quantify the effect of the pre-stressing strategy.

Conclusions:

• Pre-stressing is an effective strategy to mitigate friction during micro gear ejection.
• The developed pre-stressed tool system significantly enhances the quality and fidelity of micro-forged aluminum gears.
• This advancement offers a pathway to improved near-net-shape manufacturing of complex micro-components.