Tool Wear and Thermal Aspects of machining

This article is about the financial services company. For the department store, see Wise Company. For other businesses named Wise, see Wise (disambiguation) § Businesses.
Wise (formerly TransferWise) is a UK-based foreign exchange financial technology company founded by Estonian businessmen Kristo Käärmann and Taavet Hinrikus in January 2011.[2][3][4] Wise specializes in cross-border payment transfers. As of 2023, it offers three main products: Wise Account, Wise Business, and Wise Platform.[1]

1. Tool Wear and Tool Life New tool has sharp cutting edges and smooth flank *Forces concentrated over a small contact area *High temperature and stress concentration-Wear 2.Because of wear-frequent tool change – machining time lost – productivity 3.Tool life is important to save time and productivity and also knowledge of tool wear is important.

2. Common wear mechanism Abrasion Adhesion Diffusion Fatigue Electrochemical Oxidation Chemical Decomposition

3. Fatigue Wear During machining, interlocking of asperities occur by which compressive stresses are generated on one side and tensile stresses on other side. If asperites pair up, stresses cancel out and relieved But new asperities form ,cycle repeats ….cyclic stresses Formation of crack and crumbling of hard material Electrochemical Wear Due to high temperature emf is setup in a closed circuit -Flow of current -Wear occurred

4. Oxidation Wear Surfaces reacted with atmospheric oxygen and form abrasive oxide (flank wear) Chemical Decomposition Localised chemical reaction weakens the tool B ecause of formation of weak compound and dissolution of bond between binder and hard constitutes weaker surface easily torn away.

5. Buildup Edge

6. Tool Geometry vs Tool Life

7. Tool life test in turning yield the following data (1) v=100m/min, T=10min (2) v=75m/min, T=30 min (a) Determin the n and C values in the taylor tool life equation .Based on this question compute (b) the tool life for a speed of 90 m/min and (c) the speed corresponding to a tool life of 20 min Numerical

8. T urning tests have results in 1 min tool life for a cutting speed of v=4m/s and a 20 min tool life at a speed v= 2.0 m/s.(a) find the n and c values in the taylor tool life equation (b) Project how long the tool would last at a speed v=1.0m/s. Numerical

9. Thermal Aspect of Machining

10. Average Shear plane Temperature

11. Machinability Ease of machining or ease with which a given work material can be machined under a given set of cutting conditions Economically important for production engineer to know in advance of machinability of work material so that he can planned efficiently. Machinability Criteria Ease of machining of different material can be compared in terms of Tool Life Cutting forces Surface finish Cutting Temperature Chip Disposal Operator safety