1. Manufacturing Processes
Tools
Manufacturing
Processes

2. Outline Types of Tools Tool Geometry Cutting Fluids Tool Wear
Effects
Types
Tool Wear
Forms
Causes
Failure Modes
Critical Parameters
Horsepower Used
Operating Temperature
Feed and Speed
Tool Life

3. Types of Tools

4. Tool Geometry Single Point Tools Multiple Point Tools Chip Breakers
Effects of Material on Design

5. Single Point Tools

6. Multiple Point Tools

7. Chip Breakers

8. Important Tool Properties
High hardness
Resistance to abrasion, wear and chipping of the cutting edge
High toughness/impact strength
High hardness at high temperatures
Resistance to bulk deformation
Chemical stability (does not react or bond strongly with the work material
High modulus of elasticity (stiffness)
Consistent tool life
Proper geometry and surface finish

9. Tool Materials Carbon and medium-alloy steels High-speed steels
Cast-cobalt alloys
Carbides
Coated tools
Alumina-based ceramics
Cubic boron nitride
Silicon-nitride-base ceramics
Diamond
Whisker-reinforced materials

10. Cutting Speeds of Tool Materials

11. Cutting Fluids Effects Types coolant lubricant flushes chips
reduces oxidation of heated surfaces
Types
cutting oils
emulsified oils
chemical fluids

12. Cutting Fluid Application
Flooding
≥ 3 gallons per minute per tool
Misting
atomized fluids
a health hazard (OSHA limit = .2 mg/m3)
High Pressure Systems
often applied through the tool

13. Tool Wear Forms Causes crater wear flank wear chipping abrasion
adhesion
diffusion
plastic deformation

14. Crater Wear and Flank Wear

15. Failure Modes
Fracture
Temperature Failure
Gradual Wear

16. Critical Parameters
Horsepower Used
Operating Temperature

17. Horsepower Used Values of Unit Horsepower for Various Work Materials
Brinell
Hardness
Unit Horsepower
hpu hp/(in3/min)
Carbon
Steels
0.6
0.8
1.0
Cast
Irons
0.4
Aluminum
50-100
0.25

18. Operating Temperature

19. Feed and Speed
Speed – the rate at which the tool point moves as it rotates (in a lathe, the rate at which the cutting point on the workpiece rotates)
Feed – the rate at which the tool is fed into/along the workpiece

20. Feed and Speed V = πDN/12 V = surface cutting speed (ft/min)
D = diameter of rotating object (in.)
N = rotation rate (RPM)

21. Feed and speed
Example: Assume a high-speed steel saw with 100 teeth and a diameter of 6 inches is used to cut aluminum. Determine the proper RPM and feed rate.
V (HSS, aluminum) = ft/min [in table]
N = 12V/(πD) = 12( )/(π6)
= RPM
Feed (aluminum, saw) = in/tooth [in table]
( )100 teeth = .6-1in
(.6-1)350 RPM = in/min
Start with the lowest values. They can be increased so long as the finish is acceptable.

22. Taylor Tool Life Equation
F. W. Taylor, 1907
Taylor Tool Life Equation
vTn = C
vTn = C(Tn )
ref

23. Cutting Performance How do we know if cutting parameters are optimal?
Surface finish
Tool wear
Chip shape
Sound
Cutting time
Heat

24. Summary Tools fail slowly with gradual wear or suddenly with fracture
Cutting fluids help reduce the effects of wear and temperature failure
The materials of the tool and the workpiece affect the tool shape and life
Higher cutting speeds increase the operating temperature and decrease tool life
It is necessary to calculate proper feed and speed to prevent excessive tool wear

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The End