1. Manufacturing Processes
Automated Machining
Manufacturing Processes

2. Outline Machining Centers Equipment Manufacturing Cells
Tool Changers
Centering and Clamping
Selection of Equipment
Selection of Tooling
Machine Performance Monitoring
Manufacturing Cells
Manufacturing Economics

3. Machining Centers Machining Center
A computer-controlled machine tool capable of many types of cutting operations on multiple surfaces and directions on a workpiece

4. Manufacturing CentersZ Y X
3-Axis Operation φ
4-Axis Operation φ θ
5-Axis Operation

5. Components of a Machining Center

6. Example of a Machining Center

7. Example of a Machining Center

8. Example of a Machining Center
Example of a 5-axis CNC machine (the tool pivots instead of the workpiece)

9. Example of a Vertical Machining Center

10. Example of a Horizontal Machining Center

11. Examples of Manufactured Parts

12. Automated Robotic Loading

13. Automated Robotic Loading

14. Equipment
Pallets
The workpiece is placed on a pallet (module) which can be oriented in different directions by the machine
Automatic Pallet Changers
When the workpiece is finished, automatic pallet changers remove it and replace it with another workpiece

15. Pallets
Example of a part mounted on a pallet
Courtesy Toth Industries

16. Pallet Changers

17. Equipment Automatic Tool Changer
Can switch between up to 200 tools stored in a magazine, drum, or chain
Tool Exchange Arm
Picks up particular tools with attached toolholders

18. Tool Changer Types Automatic (Sequential) Spindle
Turns one increment in one direction for each tool change; tools must be placed in the spindle in the order they are used
Indexable (Random Access) Spindle
Turns either direction to make a specific tool accessible; tools can be placed in any order as long as the computer knows their positions

19. Tool Changer Types Sequential Spindle Random Access Spindle 2 3 1 4 65
Sequential Spindle 8 1 4 6 2 5 3 7
Random Access Spindle

20. Tool Changer Spindle

21. Tool Changer Spindle Tool changer spindle capable of holding 60 tools
Courtesy of Toth Industries

22. Tool Changer Arm

23. Tool Changer Arm

24. Tool Changer Arm

25. Tool Changer – Live Spindle

26. Types of Manufacturing
Cutting From Bulk Material
Starting with a readily available shape (rods, ingots etc.) and machining the part from this
Cutting From Near Net Shape
Starting with a pre-formed (often cast) piece with the general shape of the part and removing little material

27. Centering and Clamping
Pre-cast designs should be made so that the machines can clamp and orient them quickly and accurately
Parts to be lathed should have radially symmetrical outer surfaces and pre-cast holes to mark the center; they should also have a center of mass on the center line to prevent vibration

28. Orienting and Clamping
notches
holes
Pre-cast parts should have at least three distinct features that the computer can recognize and use to orient the part

29. Centering and Clamping
Pre-cast parts should have flat parallel surfaces for clamping or cylindrical surfaces for chucking
Areas to be clamped or chucked can be ground flat after casting to improve grip

30. Selection of Equipment
Various types of parts may require various machining centers
Parts with numerous cylindrical surfaces (or other radially symmetrical surfaces) should be mounted on a machine center capable of turning
Specialized machine centers are available for high-speed machining and for ultraprecision cutting

31. Selection of Equipment
Example: Pump Cover
Starting with the rough casting, drill and ream the center hole, then cut the internal notch with a milling cutter. Mount the piece on a mandrel and use turning operations to cut the faces and outer edge. Mill the external notch and drill and ream the smaller holes in the plate.

32. Selection of Tooling
The proper selection of tools depends on the workpiece material, size and shape of holes, radii of the corners of milling pockets, and various other parameters
The selection of tools affects the cost and time of the operation

33. Machine Performance Monitoring

34. Machine Performance MonitoringY Y’
Part Orientation X’ X
Cutting Performance

35. Machine Performance Monitoring
Tool/Part-Checking Station
Measures workpieces and tools so that the computer can compensate for variations and tool wear
Touch Probes
Pressed against a workpiece or tool to measure its exact size and position

36. Touch Probes

37. Measurement and Adjustment
critical distances
Holes to be drilled
(initial)
Holes to be drilled
(adjusted)
Advanced machining software can use data from probes to adjust its coordinate system, ensuring that critical distances remain within tolerances even in deformed workpieces

38. Touch Probes tool holder probe part
Using a touch probe to measure a part
Courtesy Toth Industries

39. Touch Probes A machining center, being used to measure and determine
the orientation of a part
Courtesy of Toth Industries

40. Courtesy of Toth Industries
Touch Probes
tool changer arm
probe
part
A machining center, being used to measure and determine the orientation of a part
Courtesy of Toth Industries

41. Courtesy of Toth Industries
Touch Probes
To determine the orientation of the part, the machine measures the two large holes and calculates their centers. A line constructed between the centers serves as a base for the computer’s coordinate system.
Courtesy of Toth Industries

42. Machine Performance Monitoring
Tool Failure Detection:
Time
When the total cutting time of the tool exceeds the pre-programmed tool life, the tool is replaced
Horsepower
Dull tools draw more power; if the power exceeds pre-programmed limits, the tool is replaced

43. Machine Performance Monitoring
Tool Failure Detection:
Acoustic Emissions
Cutting tools produce ultrasonic vibrations and weakened ones produce up to five times the normal amplitude; when it rapidly increases, the tool is immediately replaced

44. Machine Performance Monitoring
Tool Failure Detection:
Feed Force
Records the feed force of sharp tools; if the force increase exceeds a predetermined percentage, the tool is replaced; if the force suddenly rises, the tool has broken and is replaced immediately

45. Manufacturing Cells

46. Manufacturing Cells

47. Manufacturing Cells

48. Manufacturing Cells – Examples
Courtesy of Toth Industries

49. Manufacturing Economics
Cost:
If the cutting speed is too low, the cost of cutting increases because of increased power consumption
If the cutting speed is too high, the cost of tool replacement increases because tools wear out faster

50. Manufacturing Economics
Time:
If the cutting speed is too low, the cutting time increases
If the cutting speed is too high, the tool replacement time increases

51. Manufacturing Economics

52. Summary
Machining Centers allow increased automation and efficiency, especially in large-scale production
Monitoring, by an operator or the machine itself, is necessary to prevent damage to the parts produced
Cutting speed can be varied to minimize the total cost or time of the operation

53. The End