Optimal tool design in micro-milling of difficult-to-machine materials

Area of Science:

• Manufacturing Engineering
• Materials Science
• Mechanical Engineering

Background:

• Commercial micro-end mill tools suffer from tool wear and breakage, especially with difficult-to-machine (DTM) materials.
• Scaling down macro-tool designs to micro-scale results in poor rigidity, strength, and weak cutting edges, leading to manufacturing inefficiencies and poor surface quality.
• DTM materials like superalloys and ceramics are crucial for orthopaedic implants and micro-feature molds.

Purpose of the Study:

• To establish an optimal design process for micro-end mill tools tailored for DTM materials.
• To enhance tool stiffness and mechanical strength to minimize wear, chipping, and breakage.
• To improve the efficiency and surface quality in micro-milling DTM materials.

Main Methods:

• A design process was developed focusing on stiffness and strength for DTM materials.
• Static stress and deflection finite element analysis (FEA) was performed to evaluate tool design.
• FEA results were optimized to establish a verified optimum tool design.
• An experimental study compared the optimized design against commercial tools.

Main Results:

• The optimized micro-end mill design demonstrated improved stiffness and mechanical strength.
• FEA identified and mitigated design flaws related to stress distribution and deformation at the cutting edge.
• Experimental results showed reduced cutting forces and tool wear, along with enhanced surface quality compared to commercial tools.

Conclusions:

• The developed design process yields an optimal micro-end mill tool for machining DTM materials.
• The optimized tool design significantly reduces tool wear and breakage, leading to more efficient and reliable manufacturing.
• This advancement is critical for producing high-quality orthopaedic implants and micro-feature molds.