1. Group #3 Erica Velarde, Sean Clifton David Pincus, Ruben Sosa
Machining Processes
Group #3
Erica Velarde, Sean Clifton
David Pincus, Ruben Sosa

2. Typical Parts Made with These Processes
Machine Components
Engine Blocks and Heads
Parts with Complex Shapes
Parts with Close Tolerances
Externally and Internally Threaded Parts

3. Products and Parts Made By These Processes

4. Alternative Processes
Precision Casting
Powder Metallurgy
Powder Injection
Molding
Abrasive Machining
Thread Rolling

5. The Turning Process Using Engine Lathes
Operate on all Types of Materials
Use of single-point tools
Skilled Labor
Low Production Rate

6. Tool Geometry Rake Angle Side Rake Angle Cutting-Edge Angle
Relief Angle
Nose Radius

8. Typical Lathe and Its Various Components

9. Lathe Components
Bed: Usually made of cast iron. Provides a heavy rigid frame on which all the main components are mounted. • Ways: Inner and outer guide railsn that are precision machined parallel to assure accuracy of movement. • Headstock: mounted in a fixed position on the inner ways, usually at the left end. Using a chuck, it rotates the work. • Gearbox: inside the headstock, providing multiple speeds with a geometric ratio by moving levers.

10. • Spindle: Hole through the headstock to which bar stock can be fed.
• Chuck: 3-jaw (self centering) or 4-jaw (independent) to clamp part being machined.
• Tailstock: Fits on the inner ways of the bed and can slide towards any position the headstock to fit the length of the work piece. An optional taper turning attachment would be mounted to it.
• Tailstock Quill: Has a Morse taper to hold a lathe center, drill bit or other tool.
• Carriage: Moves on the outer ways. Used for mounting and moving most the cutting tools.
• Cross Slide: Mounted on the traverse slide of the carriage, and uses a handwheel to feed tools into the workpiece.

11. • Tool Post: To mount tool holders in which the cutting bits are clamped.
• Compound Rest: Mounted to the cross slide, it pivots around the tool post.
• Apron: Attached to the front of the carriage, it has the mechanism and controls for moving the carriage and cross slide.
• Feed Rod: Has a keyway, with two reversing pinion gears, either of which can be meshed with the mating bevel gear to forward or reverse the carriage using a clutch.
• Lead Screw: For cutting threads.
• Split Nut: When closed around the lead screw, the carriage is driven along by direct drive without using a clutch.

12. • Quick Change Gearbox: Controls the movement of the carriage using levers.
• Steady Rest: Clamped to the lathe ways, it uses adjustable fingers to contact the workpiece and align it. Can be used in place of tailstock to support long or unstable parts being machined.
• Follow Rest: Bolted to the lathe carriage, it uses adjustable fingers to bear against the workpiece opposite the cutting tool to prevent deflection.

13. Lathe Accessories Carriage and Cross Slide Stops
Devices for Turning Parts with Various Tapers
Milling, Sawing, Gear-Cutting, and Grinding Attachments
Various Attachments for Boring, Drilling, and Thread Cutting

14. Typical Lathe and Its Various Components

15. More Tool Geometry

16. Lathe Operations Form Tools Boring Drilling Parting Grooving
Thread Cutting
Knurling

17. Cutting Operations Performed on a Lathe

18. Above Left: Example of Boring Above Right: Example of Drilling Below Left: Example of Thread Cutting Below Right: Example of Grooving

19. Types of Lathes Bench Lathes Special Purpose Lathes Tracer Lathes
Automatic Lathes
Automatic Bar Machines
Turret Lathes
Computer-Controlled Lathes

21. Turret Lathe

22. Computer-Controlled Lathe

23. Things to Remember About Machining Parts on Lathes
Takes considerable amount of time
High Production Costs
Wastes Material
Not as Economical as Forming or Shaping

25. Boring, Drilling, Reaming, and Tapping
Machining Processes
Boring, Drilling, Reaming, and Tapping

26. Boring and Boring Machines

27. What is Boring Performed to enlarge a hole made previously.
Used for circular internal profiles in hollow workpieces

28. Boring Machines Small pieces – lathe Large pieces – boring mill
Horizontal vs Vertical
Boring mills
Perform various operations: TURNING, FACING, GROOVING, CHAMFERING

29. Horizontal Boring Mill

30. Vertical Boring Mill
Large pieces can be machined on a vertical mill

31. Jig Boring Machines Vertical machines High precision bearings
Used to make jigs and fixtures
Being replaced by CNC boring machines

32. Considerations
Through holes, rather than blind holes, should be specified.
Smaller length-bore diameter ratios
Interrupted internal surfaces should be avoided.

33. Drilling, Drills, and Drilling Machines

34. What are Holes used For? Typical for assembly with fasteners
i.e. screws, bolts, rivets
Weight reduction
Ventilation
Access to inside parts
Appearance

35. Drilling is a Common Process!!!
THE COST OF HOLE MAKING IS AMONG THE HIGHEST MACHINING COSTS IN AUTOMOTIVE ENGINE PRODUCTION

36. Properties
Burring on the bottom surface upon breakthrough requires further machining
Diameters of holes are usually oversize
Quality of drill
Thermal properties
Reaming and honing improve dimensional accuracy

37. Standard-Point Twist Drill
Point angle ( deg)
Lip-relief angle (7-15deg)
Chisel-edge angle ( deg)
Helix angle (15-30deg)
Diameter range from mm

39. Other Types of Drills Step Drill Core Drill
Produces 2 or more different diameters
Core Drill
Makes an existing hole larger
Counterboring & Countersinking
Produce depressions on the surface to accommodate the heads of screws/bolts

41. More Drill Types Center drill Spot drill Spade drill
Produces small hole on the end of a workpiece
Spot drill
Starts a hole at the desired location
Spade drill
Removable bits, produces large-diameter or deep holes
Higher stiffness (absence of flutes)
Straight-flute drill
Gun drill

42. Gun Drill

43. Trepanning
Removes a disk to create a hole

44. Material-Removal Rate
MRR=(pi*D^2)f*N / 4
Pi*D^2 / 4= cross sectional area
F = the distance penetrated per revolution
N = rotational speed

45. General Troubleshooting
Problem
Probable causes
Drill breakage
Dull bit, chips clogging flutes, feed to high, lip relief angle too small
Excessive drill wear
Cutting speed to high, ineffective fluid, rake angle too high, drill burned when sharpened
Tapered hole
Drill misaligned or bent, lips not equal
Oversize hole
Same as above, machine spindle loose, chisel edge not central, side force on workpiece
Poor hole surface finish
Dull bit, ineffective fluid, welding of workpiece on drill margin, improperly ground drill, improper alignment

46. Reaming and Reamers

47. Considerations Drilling should be perpendicular to the surface
Interrupted holes should be avoided
Hole bottoms should match standard drill point angles
Through holes preferred to blind holes
Preexisting holes or dimples help center the drill
Blind holes must be drilled deeper than subsequent reaming or tapping operations

48. What is Reaming
An operation used to make an existing hole dimensionally more accurate and/or to improve surface finish
For further accuracy and surface finish, holes may be burnished, ground or honed.

49. 4 Steps to Accuracy
Centering
Drilling
Boring
Reaming

50. Tapping and Taps

51. Tapping Produces threads May be done by hand or machine
Chipless tapping is a process of internal thread rolling

53. Milling and Milling Machines

54. Milling
The Process of cutting away material by feeding a workpiece past a rotating multiple tooth cutter.

55. Types of Milling

56. Peripheral Milling
Peripheral Milling is when the cutter is longer than the width of the cut.
a.k.a.- Slab Milling
The axis of the cutter is usually parallel to the work piece surface.

57. Face Milling
the cutter is mounted on a spindle having an axis of rotation perpendicular to the workpiece surface.
Leaves feed marks on the machined surface.

58. End Milling
The cutter generally rotates on an axis vertical to the workpiece.
It can be tilted to machine tapered surfaces. Cutting teeth are located on both the end face of the cutter and the periphery of the cutter body.
Can produce a variety of surfaces at any depth.

59. Conventional Milling a.k.a- Up Milling
The Direction of cutter rotation opposes the feed motion.

60. Climb Milling a.k.a.- Down Milling
The direction of cutter rotation is the same as the feed motion.

61. Other Types of Milling Straddle Milling Form Milling
Slotting and Slitting
Uses circular cutters

62. Tool holders Arbor Cutters Mounted on an arbor
Used in peripheral, face, straddle and form milling.

63. Shank-Type Milling
Cutter and shank are one peice

64. Design and Operating Guidelines
Basic cutters should be used as much as possible.
Avoid expensive special cutters.
Chamfers should be specified instead of radii.
Chamfer-A furrow or groove, as in a column.
Avoid internal cavities and pockets with sharp corners.
Due to the difficulty of doing them.

65. Troubleshooting
Tool Breakage Tool material lacks toughness, improper angles.
Excessive Tool Wear improper tool material, improper tool fluids.
Rough Surface Finish Feed per tooth too high, tool chipped or worn.
Chatter Marks Insufficient stiffness of system, external vibrations.
Breakout Lead angle too low, feed and depth of cut too high.

66. Milling Machines
First Milling Machine
Built in 1820 by Eli Whitney

67. Column-and-Knee type
Most common milling machines.

68. Basic Components
Work Table
Saddle
Knee
Overarm
Head

69. Bed Type Work table is mounted is mounted directly on the bed.
Not versatile
High Stiffness
Used for high production work

70. Other Milling Machines
Planer-Type
Several heads and cutters able to mill different surfaces
Rotary-Table
One or more heads for face milling.
Computer Numerical Control
Able to mill, drill, bore and tap with repetitive accuracy
Profile Milling Machines
5 axes of movement.

71. Planning and Shaping Planning Shaping Large workpieces 25m X 15m
Work piece is mounted on a table and travels back and forth along a straight path.
Cutting speeds can get up to 120 m/min with 150 hp
Shaping
Tool does the moving
Small less than 1m X 2m

73. introduction Broaching and Broaching machines Sawing Filing
Gear Manufacturing by Machining

74. Broaching and Broaching machines
Broaching is a similar technique to shaping with a long multiple-tooth cutter and is used to machine internal an external surfaces.

75. Broaching is just as effective as
Boring
Milling
Shaping
Reaming

76. Broaching machines are very expensive but these machines yield a very high quantity of production runs.

77. Uses a single pass for finished shapes or sized
Produces close tolerances and good surface finish
Uses a multipoint cutting tool (broach)
Has the roughing and finishing teeth on the same tool

78. Sawing
Sawing is an old common operation dating back to around 1000 B.C
Sawing is an efficient bulk removal process and can produce near net shape materials
The process wastes little material
Most common use of saws
Hacksaws
Circular saws
Band saws
Friction sawing

79. Samples of various sawing operations

80. Hacksaws Hacksaws were developed in the 1960’s.
Good for cutting off bars, rods, and structural shapes

81. Power hacksaws
Fast
They work smoothly and efficiently even under heavy-duty operation. With normal care these machines are indestructible.

82. Circular sawing
Circular sawing is a multipoint cutting process in which a circular tool is advanced against a stationary workpiece to sever parts or produce narrow slots.
Uses thin circular blades with teeth on periphery
Rotating blade is fed into a stationary workpiece
Produces a narrow cut and a good surface finish

84. Diamond Saw Blades For Marble And Limestone
Circular saws also called cold saws when cutting metal
They are used for high production rate sawing
Cold sawing is used in industry very commonly particularly for cutting large crossed sections.
Diamond Saw Blades For Marble And Limestone
saw blade for plastics

85. Types of cold sawing machines

86. Band saw Uses a flexible steel band with a toothed edge
Workpieces are fed into the cutting edge on vertical machines
Can produce straight, irregular, or curved cuts

87. Friction sawing Workpieces are fed into a continuously moving band
Produces fine, accurate work
Is a finishing operation in which small amounts of material are removed

88. Gear Manufacturing by Machining
Several processes for making gears
Form cutting (form-milling)
Gear generating (Hobbing, Shaping)

89. Gear milling
Uses a rotating form cutter
Gear blanks are indexed after each cut
Is a low production process
Gear teeth are produced individually

90. Gear generating
This particular machine removes over 17 lb of 8822 steel from a 100-lb, 18-in.-diameter gear in under 12 min

91. Gear Hobbing
Is a gear generating process that uses a helical hob cutter
Cuts several teeth on a progressive basis
Is used for high production runs

92. Gear shaping
Cutters rotate in timed relationship with the workpiece
Produces internal gears, external gears, and integral gear-pinion arrangements

93. References

94. http://www. manufacturingcenter. com/tooling/archives/0604/0604cooling