Understanding the Relationship between Surface Quality and Chip Morphology under Sustainable Cutting Environments

Area of Science:

• Materials Science
• Manufacturing Engineering
• Tribology

Background:

• Chip morphology significantly impacts machined surface quality, especially for difficult-to-machine materials.
• Understanding the relationship between chip formation and surface integrity is crucial for optimizing machining processes.

Purpose of the Study:

• To analyze chip morphology, surface morphology, and surface quality criteria (Ra and Rz) during the milling of precipitation-hardened steel.
• To evaluate the effect of various cutting environments on these parameters.

Main Methods:

• Milling experiments were conducted on precipitation-hardened steel using TiAlN-coated inserts.
• Cutting environments included dry, minimum quantity lubrication (MQL), nano-MQL (graphene, hBN), Cryo, and Cryo-MQL.
• Varying cutting speeds and feed rates were employed.

Main Results:

• Dry machining resulted in the highest Ra and Rz values.
• Nano-MQL (hBN) environment yielded the minimum Ra and Rz values (0.304 µm and 1.825 µm).
• MQL environments promoted thinner, segmented chips, reducing chip curve radius and stabilizing surface morphology.

Conclusions:

• Nano-MQL cutting environments, particularly with hBN, are highly recommended for improving surface quality in milling operations.
• The study demonstrates a clear correlation between cutting environment, chip morphology, and achievable surface finish.