Factors affecting tool life in machining processes

1. Factors Affecting Tool Life In Machining Processes

2. Factors Affecting Tool Life In Machining Processes What are these??

3. ME 572 Analysis of Manufacturing Processes Mohammad AlJuhani

4. Factors Affecting Tool Life In Machining Processes CONTENTS Introduction Tool Life and Machinability Tool Damage Causes of tool damage Factors Affecting Tool Life in Machining Processes

5. Factors Affecting Tool Life In Machining Processes INTRODUCTION Cutting tool life is important consideration in metal cutting processes. In machining operations, cutting conditions such as tool angles, cutting speeds and feed rates are usually selected to give an economical tool life. Conditions giving a short tool life are uneconomical because tool grinding and tool replacement costs are high. Factors affecting tool life should be carefully monitored to minimize their consequences.

6. Factors Affecting Tool Life In Machining Processes A tool that doesn’t perform the desired function can be declared as failed, or reached the end of its useful life. At this point of time, the tool is not necessarily unable to cut the workpiece but is merely unsatisfactory (may not give the desired surface finish or dimensional tolerances) for the purpose required The tool life is defined as the length of cutting time that the tool can be used . Tool Life and Machinability

7. Factors Affecting Tool Life In Machining Processes Tool damage can be classified into two groups, wear and fracture by means of its scale and how it progresses. Wear is loss of material on an asperity or micro-contact, or smaller scale, down to molecular or atomic removal mechanisms. It usually progresses continuously . There are two main types of tool wear Flank wear Crater wear Fracture, on the other hand, is damage at a larger scale than wear and it occurs suddenly. Tool Damage

8. Factors Affecting Tool Life In Machining Processes Tool damage. Flank wear vs. cutting time

9. Factors Affecting Tool Life In Machining Processes Causes of tool damage

10. Factors Affecting Tool Life In Machining Processes Mechanical Damage It is independent of temperature. Causes of tool damage

11. Factors Affecting Tool Life In Machining Processes Causes of tool damage Mechanical Damage

12. Factors Affecting Tool Life In Machining Processes Thermal Damage It increases drastically with increasing temperature Causes of tool damage

13. Factors Affecting Tool Life In Machining Processes Thermal Damage Causes of tool damage

14. Factors Affecting Tool Life In Machining Processes Thermal Damage Causes of tool damage

15. Factors Affecting Tool Life In Machining Processes Occurs when work or chip material welds to the tool surface. Adhesion Damage Causes of tool damage

16. Factors Affecting Tool Life In Machining Processes Causes of tool damage

17. Factors Affecting Tool Life In Machining Processes

18. Factors Affecting Tool Life In Machining Processes Cutting Tool Geometry

19. Factors Affecting Tool Life In Machining Processes Cutting Tool Geometry

20. Factors Affecting Tool Life In Machining Processes Cutting Tool Geometry

21. Factors Affecting Tool Life In Machining Processes Rake angle Rake angles are three types, positive, zero and negative. For ductile materials , the rake inclination is a positive angle Since their shearing is low. For brittle materials , the rake inclination is a negative angle. The advantages of increasing rake angle Reduces the horsepower consumption. The cutting force and tool-chip contact temperature change in approximately the same way. The disadvantages of increasing rake angle The strength of the cutting wedge decreases when the rake angle increases. The region of the maximum contact temperature at the tool-chip interface shifts toward the cutting edge. Cutting Tool Geometry

22. Factors Affecting Tool Life In Machining Processes Flank angle The flank angle affects the performance of the cutting tool mainly by decreasing the rubbing between the tool surface and workpiece surface . With increasing the flank angle the following advantages are obtained: Cutting edge radius decreases which leads to decrease in the frictional and deformation components of the flank force. The strength of the region adjacent to the cutting edge decreases. Heat dissipates through the tool decreases. Cutting Tool Geometry

23. Factors Affecting Tool Life In Machining Processes Nose Radius Nose radius is very critical part of the cutting edge. If the radius is made of sharp angle, the produced finished surface will be rough and tool life will be short. A large nose radius benefits Better surface finish. Faster feed rate. Stronger tool. Allow faster cutting speed However, large radii have negative sequences such as tool chatter . Cutting Tool Geometry

24. Factors Affecting Tool Life In Machining Processes Cutting Tool Material

25. Factors Affecting Tool Life In Machining Processes Cutting Tool Material

26. Factors Affecting Tool Life In Machining Processes Cutting Tool Material

27. Factors Affecting Tool Life In Machining Processes Today , 50% of HSS, 85% of carbide and 40% of super-hard tools used in industry are coated Cutting Tool Material

28. Factors Affecting Tool Life In Machining Processes Cutting Tool Material Uncoated cutting tool Coated cutting tool

29. Factors Affecting Tool Life In Machining Processes Cutting Tool Characteristics

30. Factors Affecting Tool Life In Machining Processes Cutting Conditions

31. Factors Affecting Tool Life In Machining Processes Cutting speed has the greatest influence on tool wear and tool life . Most materials can be machined over a wide range of speeds . When a shorter tool life is allowable the speed can be increased Relationship between tool life and cutting speed is expressed by Taylor equation for tool life   Cutting Conditions

32. Factors Affecting Tool Life In Machining Processes Cutting Conditions

33. Factors Affecting Tool Life In Machining Processes Feed rate changes have a less effect on tool life than cutting speed does. Relationship between tool life and cutting conditions is expressed by modified Taylor equation Limitations to maximizing feed rate Horsepower available on the machine tool. Chip groove geometry. Surface finish required. Part configuration.   Cutting Conditions

34. Factors Affecting Tool Life In Machining Processes Cutting Conditions

35. Factors Affecting Tool Life In Machining Processes Depth of cut has least effect upon tool life, so the heaviest (10 times the feed rate) possible depth of cut should always be used. Depth of cut is limited by Amount of metal to be machined from the workpiece, Power available on machine tool, Rigidity of the work piece and cutting tool Rigidity of the setup. Workpiece configuration Insert size & thickness Cutting Conditions

36. Factors Affecting Tool Life In Machining Processes Cutting Conditions

37. Factors Affecting Tool Life In Machining Processes Workpiece Material.

38. Factors Affecting Tool Life In Machining Processes Workpiece Material.

39. Factors Affecting Tool Life In Machining Processes Cutting Fluid

40. Factors Affecting Tool Life In Machining Processes Cutting Fluid

41. Factors Affecting Tool Life In Machining Processes Cutting Fluid

42. Factors Affecting Tool Life In Machining Processes Cutting Fluid

43. Factors Affecting Tool Life In Machining Processes Cutting Fluid

44. Factors Affecting Tool Life In Machining Processes Cutting Fluid

45. Factors Affecting Tool Life In Machining Processes

46. Thank you Factors Affecting Tool Life In Machining Processes

47. Factors Affecting Tool Life In Machining Processes Cutting Tool Geometry