BUE and its Influence on Surface Finish-CuttingTool Materials andMachining Induced Surface Integrity | Summary and Q&A

TL;DR

This video discusses the formation of built-up edge during machining and its impact on the surface finish.

Key Insights

• 🐿️ Friction between the chip and the tool phase leads to shear and welding of the chip, resulting in the formation of built-up edge.
• 🤘 Increasing cutting speed increases ductility in the chip metal, contributing to stronger welds and strain hardening.
• 💗 Built-up edge grows in layers and can cause an increase in the rake angle, decreased resultant force on the tool, and potential undercutting of the finished surface.
• 🦔 Gradual growth and rapid decay of the built-up edge size affect the surface finish, resulting in a less smooth surface.
• 💁 Understanding built-up edge formation is important for improving surface finish in machining processes.
• 🚄 Higher cutting speeds can lead to more significant built-up edge formation.
• 🖐️ Strain hardening plays a role in anchoring the chip to the tool during built-up edge formation.

Transcript

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Questions & Answers

Q: What causes the formation of built-up edge during machining?

The formation of built-up edge is caused by friction between the chip and the tool phase, leading to shear and welding of the chip to the tool when the bonding force exceeds the shear strength of the chip.

Q: How does increasing cutting speed affect the formation of built-up edge?

Increasing cutting speed increases friction and temperature, leading to more ductility in the chip metal. This results in stronger welds and strain hardening, contributing to the formation of built-up edge.

Q: What are the effects of built-up edge on the machining process?

Built-up edge causes an increase in the rake angle, decreasing the magnitude of the resultant force on the tool. It can also cause undercutting of the finished surface and may affect the surface finish negatively.

Q: How does the size of built-up edge affect its stability?

As the built-up edge grows larger, it acts like a cantilever and becomes more unstable. Eventually, the moment at the base of the built-up edge becomes sufficient to cause it to partially break off, leading to a less smooth surface finish.

Summary & Key Takeaways

• Built-up edge formation occurs when friction between the chip and the tool phase exceeds a certain threshold, resulting in shear and welding of the chip to the tool.

• Increasing cutting speed leads to more ductility in the chip metal due to friction and higher temperature, causing stronger welds and strain hardening.

• The built-up edge grows in layers, causing an increase in the rake angle, decreased resultant force on the tool, and potential undercutting of the finished surface.