1. Lecture 1& 2 Processes & Tooling
Overview to Computer Aided Manufacturing - ENGR Fall 2008
Class Manager - Sam Chiappone

2. Featured Processes For This Class
Milling
Turning
Drilling

3. Milling Processes
Milling is one of the basic machining processes. Milling is a very versatile process capable of producing simple two dimensional flat shapes to complex three dimensional interlaced surface configurations.

4. The Process The milling process: Typically uses a multi-tooth cutter
Work is fed into the rotating cutter
Capable of high MRR
Well suited for mass production applications
Cutting tools for this process are called milling cutters

5. Classifications
Milling operations are classified into two major categories:
Peripheral (side)
Generally in a plane parallel to the axis of the cutter
Cross section of the milled surface corresponds to the contour of the cutter
Face
Generally at right angles to the axis of rotation of the cutter
Milled surface is flat and has no relationship to the contour of the cutter
Combined cutting action of the side and face of the milling cutter

6. Related Operations
Thread milling - milling treads using the capability of a three axis contouring CNC machine.

7. Operating Parameters Rpm Feed rate
CS converted into Rpm based on cutter diameter
Feed rate
Feed per tooth
Table feed rate

8. Operating Parameters Feed direction -- Conventional vs. Climb
Conventional milling
Most common method of feed
Feed work against the rotation of the cutter

9. Operating Parameters Feed direction - Conventional vs. Climb
Climb milling
Load of the cutter tends to “pull” the work into the cutter
This results in a small feed force and about 20% less Hp than conventional milling
Downward motion increases the load on the table ways
This method can “pull” the work into the cutter and scrap the work and/or damage the fixture and tool.
Machine must be very ridged to safely utilize climb milling(CNC machines)
USE CAUTION!

10. Operating Parameters
Conventional vs. Climb Milling

11. Operating Parameters
Depth of cut
Horsepower

12. Milling machines Two Major Classifications - Knee & Column and Bed
Knee & Column (Bridgeport type)
Basic job shop type mill
Column mounted to the base which is the major support frame.
Construction provides controlled motion of the worktable in three mutual perpendicular directions.
Knee moves vertically on the ways in the front of the machine
Table moves longitudinally on the ways on the saddle
Saddle moves transversely on the ways on the knee
Quill moves parallel in Z axis or, if head is rotated, X axis
Versatile general purpose machine

13. Milling Machines Bed Used extensively in production milling operations
Rigid construction capable of heavy cuts
Table is mounted directly to the bed
Spindle head moves vertically to set depth of cut
Head locks into position for cut
Base of machine functions as a coolant reservoir

14. Machines
Conventional
Computer
Numerical
Control

15. Milling Machines

16. Milling Machines

17. Milling Machines

18. CNC Machines
CNC
Horizontal, Vertical,and Planner (up to 5 axis)

19. Process Accuracy Accuracy of milling machines Factors to consider
Fixture
Rigidity of machine tool
Accuracy of the spindle
Cutter condition
Coolant
Type
Delivery method
Material condition

20. Process Accuracy +/- .0005” - Optimum situation
+/- .001”-.002” - Typical
+/- .001” - Flatness

21. Milling Cutters & Holding Systems
Cutter Types
2 to 4 Lip Cutters
Face Mills
Ball End Mills
Collect Holding Systems
Direct Mount Holders
Face Mill Holders

22. Milling Cutters

23. Workholding Devices for CNC Milling Machines
Vise
Chucks
Special fixtures
Modular fixturing systems
Clamp work to table

24. Workholding Devices

25. Turning
Turning is the process of machining external cylindrical and conical surfaces. The process uses a machine tool called a lathe.

26. Turning Processes
Turning typically involves roughing procedures followed by a finishing operation.

27. Turning Operations Turning operations performed on a lathe include:
Straight turning
Taper turning
End facing
Facing

28. Turning Operations Shoulder Facing Contour Turing Grooving
Form turning
Parting-off

29. Turning Operations Threading Knurling Drilling Reaming
Internal / External
Knurling
Drilling
Reaming
Milling-CNC turning centers

30. Process Calculations
Rpm calculation
RPM CS

31. Process Calculations
Feed is typically a given distance per revolution. This value is dependent on the operation, depth of cut, cutting speed, tool material, surface finish----etc. Units are--- in. per rev (in./rev)

32. Machine Classification
Size designation
Swing - maximum diameter that can be rotated on the lathe
2x’s distance from spindle center line to ways
Maximum distance between centers

33. Conventional and CNC Lathes
Engine
Most frequently used lathe
Heavy duty
Power drive for most tool movements
Size range 12”x24” to 24”x48” - can be larger
CNC
Computer controlled
Wide variety of process capability
Multiple axis
Indexing and contouring head
On- line and off- line programming available

34. Other Types of Lathes Tracer
Hydraulic attachment used to copy the shape of a part from a master.

35. Types of Lathes 1 2

36. Types of Lathes
Combination
Conventional / CNC

37. Cutting Tools for Lathes
External
Right hand turning
Left hand turning
Round nose turning
Cut-off
Left hand facing

38. Cutting tools for Lathes
External (con’t)
Broad nose finishing
Right hand facing
Threading
Form
Internal
Boring
Grooving

39. Typical Carbide Insert & Holder

40. Workholding on a Lathe Between centers Live-tailstock Dead-headstock
Face plate
Drive dog

41. Workholding on a Lathe
Chuck
3,4, or 6 jaw
Soft jaws

42. Workholding on a Lathe
Collect system

43. Workholding on a Lathe
Others
Face driver system
Sub-spindle system

44. Drilling & Related Hole Making Processes
Basic hole making processes account for approximately 50-70% of all the metal removal processes utilized today.
Holes
Casting
Sand, die, molding
Punching
Machining,
Drilling, milling, EDM, AWJ, etc.
Burning

45. Processes Standard hole making processes include:
Drilling - Drilling is the process of producing or enlarging a hole. This is accomplished by rotating the tool and/or workpiece.
Reaming - Enlarging an existing hole with a multi-edged tool (reamer) for dimensional accuracy and/or surface finish
Spot facing - Smoothing, squaring, and/or flattening a surface

46. Processes
Counter sinking - operation or producing a tapered feature at the end of a hole. Most popular application is a feature for a flathead screw (82 degrees) to sit flush with a surface.
Counter boring - Enlarging of an existing hole at one end. This enlarged hole is concentric with the existing hole and is flat at the bottom. One application of this process is a feature to set the head of a bolt below a surface.

47. Process Parameters Cutting speed Rpm
Feed (in/rev ---- in/min) (Rpm x in/rev)

48. Process Parameters

49. Drill Variations

50. Reamers

51. Machine Tools
Machine tools used in this process include; drill presses, lathes, milling machines, and special purpose machines. One of the most popular is the drill press.

52. Drill Presses Upright Drill Press Larger than the sensitive
Can be equipped with a gearbox and variable speed head
Hand and automatic feed mechanism
Automatic coolant system
Table can move on a rack and pinion system

53. Drill Presses Gang Drilling Machine
Equipped with more than one spindle
Multi-head arrangement
Single table
Used for production set-up
Multiple operations at one location (drill, ream, tap, c’sink, c’borte etc.)

54. Drill Presses CNC Turret (Conventional) 2 axis motion
Computer controlled
Series of operations
Turret indexes to different tools
Individual speeds / feeds

55. Tool Holding Devices Drill chucks Drill Sleeves Collet
Key type or keyless
Drill Sleeves
Collet

56. Lecture 2 – Tooling & Tools
Overview to Computer Aided Manufacturing - ENGR Fall 2008
Class Manager - Sam Chiappone

57. Process Basics Components Speed & Feed Calculations
Carbide Insert Specifications

58. Process Basics
Tools
Refers to devices used to cut or deform the metal.
Cutting tools - examples include end mills, carbide inserts, drills, grinding wheels, shell mills, etc.

59. Process Basics Tooling Refers to holding devices
Examples include- vises, fixtures, jigs…...etc.

60. Process Basics Cutting fluid Act as a coolant and lubricant
Reduce friction between chip and tool face
Extend tool life
Help to remove chips from cutting area

61. Metal Removal Related Calculations
To efficiently use these components, different input parameters have to be calculated. They include:
RPM of cutter
Milling or drilling operation = Rpm for cutter
Turning operation = Rpm for part
Basically the rotating component
Feed
The distance in inches, feet, or millimeters per minute that the work advances into the cutter.

62. Metal Removal Related Calculations
Input parameters (con’t)
Cutting speed(CS)-the surface feet per minute or meters per minute, at which a metal can be machined efficiently. This variable has a direct relationship to the diameter of the cutter, in a milling or drilling operation, or the diameter of the work piece in a lathe operation.
Example - When machining(using a milling machine) a medium grade steel, the cutter must achieve a surface speed of about 90 ft/min. The diameter of the cutter will have a direct relationship to the rpm calculation.

63. Metal Removal Related Calculations
Input parameters (con’t)
Depth of cut - Amount of material being removed.
Horsepower required for cut
Material removal rate (MRR) - volume of material being removed per unit of time
In a milling operation, you also have to take into account the thickness of the chip each tooth will remover per revolution as it advances into the work. This value is expressed in feed per tooth.

64. Metal Removal Problem 1.
Cutting Tools 4. 2. 3.

65. Metal Removal Problem

66. Factors Effecting Calculations
Set-up conditions
Machine conditions
Tooling conditions
Material conditions
Cutting fluid

67. Tool Selection Process

68. Tool Materials
Wide variety of materials and compositions are available to choose from when selecting a cutting tool

69. Tool Materials They include:
Tool steels - low end of scale. Used to make some drills, taps, reamers, etc. Low cost equals low tool life.
High speed steel(HSS) - can withstand cutting temperatures up to 1100F. Have improved hardness and wear resistance, used to manufacture drills, reamers, single point tool bits, milling cutters, etc. HSS cutting tools can be purchased with additional coatings such as TiN which add additional protection against wear.

70. Tool Materials
Cobalt - one step above HSS, cutting speeds are generally 25% higher.
Carbides - Most widely used cutting tool today. Cutting speeds are three to five times faster than HSS. Basic composition is tungsten carbide with a cobalt binder. Today a wide variety of chemical compositions are available to meet different applications. In addition to tool composition, coatings are added to tool materials to incerase resistance to wear.

71. Tool Materials
Ceramics - Contain pure aluminum oxide and can cut at two to three times faster than carbides. Ceramic tools have poor thermal and shock resistance and are not recommended for interrupted cuts. Caution should be taken when selecting these tools for cutting aluminum, titanium, or other materials that may react with aluminum oxide.

72. Tool Materials
Cubic Boron Nitride(CBN) - This tool material maintains its hardness and resistance to wear at elevated temperatures and has a low chemical reactivity to the chip/tool interface. Typically used to machine hard aerospace materials. Cutting speeds and metal removal rates are up to five times faster than carbide.
Industrial Diamonds - diamonds are used to produce smooth surface finishes such as mirrored surfaces. Can also be used in “hard turning” operations to eliminate finish grinding processes. Diamond machining is performed at high speeds and generally fine feeds. Is used to machine a variety of metals.

73. Carbide Inset Selection
M1-Fine
M2-Medium
M3-S.S
M4-Cast iron
M5-General Purpose
A.N.S.I. Insert Identification System
ANSI - B

74. Carbide Inset Selection