Process Engineering
Contents  3.0   Introduction  3.1   Experience-Based Planning  3.2   Decision Tables and Decision Trees  3.3   Process-Cap...
3.0 Introduction3.1   Experience-Based Planning3.2   Decision Tables and Decision Trees3.3   Process-Capability Analysis3....
Introduction• Manufacturing   • Raw material → Finished product• Process capability ismachine tools scientific knowledge f...
Process Capability• Three levels of Process Capability       Universal               Shop                Machine         -...
3.0 Introduction3.1 Experience-Based Planning3.2   Decision Tables and Decision Trees3.3   Process-Capability Analysis3.4 ...
Experience-Based Planning"The accumulation of experience is knowledge "• Problem of Experience-Based   • requires a signif...
3.0 Introduction3.1 Experience-Based Planning3.2 Decision Tables and Decision Trees3.3   Process-Capability Analysis3.4   ...
Decision Tables and Decision Trees •   Describing the actions associated with conditions •   Help systematize decision mak...
Decision Table                 i-Design Lab.
Decision Table• When constructing, consider factors   • Completeness, Accuracy, Redundancy   • Consistency, Loops, Size• M...
Decision Table• Table splitting and parsing                                i-Design Lab.
Decision Tree• Single root, Node, Branch• Branch – ‘IF’, branches in series – ‘AND’               Node                    ...
3.0 Introduction3.1 Experience-Based Planning3.2 Decision Tables and Decision Trees3.3 Process-Capability Analysis3.4 Basi...
Information Required to Make the Decision                           Shape                      Size LimitationCapability  ...
Process Boundaries• One way to represent process capability• Limiting size, tolerances, surface finish• System-dependant  ...
3.0   Introduction3.1   Experience-Based Planning3.2   Decision Tables and Decision Trees3.3   Process-Capability Analysis...
Feed and Feed Rate• Feed   • The relative lateral movement between the tool and the workpiece     during a machining opera...
Machining• Cutting Speed   • The maximum linear speed between the tool and the workpiece   • Equation (3. 18)• Depth of cu...
Machining Time• Total amount of time• Parameter   • The length of the workpiece   • Overtravel of the tool for clearance  ...
Tool Life• Erosion (Wear)   • Crater wear      • High Temperature   • Flank wear      • Friction• Breakage (Catastrophic F...
Machining Force and Power Requirements• Important considerations in selecting process parameters  (feed, speed, and depth ...
Process Parameters• Feed, Speed, Depth of cut• Process selection becomes an iterative procedure   • Process Selection   • ...
3.0   Introduction3.1   Experience-Based Planning3.2   Decision Tables and Decision Trees3.3   Process-Capability Analysis...
Process Optimization                                 Short processing time  MRR is Large (   )                            ...
Single-Pass Model• Assume that only one pass to produce the required  geometry• The depth of cut is fixed• Constraint   • ...
Multipass Model•   Assumption of single-pass model is relaxed•   Can be reconstructed into a single-pass model•   The dept...
3.0   Introduction3.1   Experience-Based Planning3.2   Decision Tables and Decision Trees3.3   Process-Capability Analysis...
Conclusion• Information of process-planning system   • Design knowledge – Chapter#2   • Process knowledge – This Chapter (...
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Process engineering

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Process engineering

  1. 1. Process Engineering
  2. 2. Contents 3.0 Introduction 3.1 Experience-Based Planning 3.2 Decision Tables and Decision Trees 3.3 Process-Capability Analysis 3.4 Basic Machining Calculations 3.5 Process Optimization 3.6 Conclusion i-Design Lab.
  3. 3. 3.0 Introduction3.1 Experience-Based Planning3.2 Decision Tables and Decision Trees3.3 Process-Capability Analysis3.4 Basic Machining Calculations3.5 Process Optimization3.6 Conclusion i-Design Lab.
  4. 4. Introduction• Manufacturing • Raw material → Finished product• Process capability ismachine tools scientific knowledge for = historic and ?? each process (≠machine tools) historic Process Process Capability Scientific knowledge i-Design Lab.
  5. 5. Process Capability• Three levels of Process Capability Universal Shop Machine -level -level -level• Important parameters • The shapes and sizes • The dimensions and geometric tolerances • The material removal rate • The relative cost • Other cutting characteristics/constraints i-Design Lab.
  6. 6. 3.0 Introduction3.1 Experience-Based Planning3.2 Decision Tables and Decision Trees3.3 Process-Capability Analysis3.4 Basic Machining Calculations3.5 Process Optimization3.6 Conclusion i-Design Lab.
  7. 7. Experience-Based Planning"The accumulation of experience is knowledge "• Problem of Experience-Based • requires a significant period of time to accumulate • represents only approximate, not exact knowledge • is not directly applicable to new processes or new systems• Machinist Handbooks • has long been a standard manufacturing practice i-Design Lab.
  8. 8. 3.0 Introduction3.1 Experience-Based Planning3.2 Decision Tables and Decision Trees3.3 Process-Capability Analysis3.4 Basic Machining Calculations3.5 Process Optimization3.6 Conclusion i-Design Lab.
  9. 9. Decision Tables and Decision Trees • Describing the actions associated with conditions • Help systematize decision making • Translate each other • Difference • Ease and elegance of presentation and programming when a computer is used ConditionAction Stub Entries i-Design Lab.
  10. 10. Decision Table i-Design Lab.
  11. 11. Decision Table• When constructing, consider factors • Completeness, Accuracy, Redundancy • Consistency, Loops, Size• Merge Merge i-Design Lab.
  12. 12. Decision Table• Table splitting and parsing i-Design Lab.
  13. 13. Decision Tree• Single root, Node, Branch• Branch – ‘IF’, branches in series – ‘AND’ Node Branch Root i-Design Lab.
  14. 14. 3.0 Introduction3.1 Experience-Based Planning3.2 Decision Tables and Decision Trees3.3 Process-Capability Analysis3.4 Basic Machining Calculations3.5 Process Optimization3.6 Conclusion i-Design Lab.
  15. 15. Information Required to Make the Decision Shape Size LimitationCapability Tolerance Surface Finish Cutting ForceLimitation Power Consumption i-Design Lab.
  16. 16. Process Boundaries• One way to represent process capability• Limiting size, tolerances, surface finish• System-dependant i-Design Lab.
  17. 17. 3.0 Introduction3.1 Experience-Based Planning3.2 Decision Tables and Decision Trees3.3 Process-Capability Analysis3.4 Basic Machining Calculations3.5 Process Optimization3.6 Conclusion i-Design Lab.
  18. 18. Feed and Feed Rate• Feed • The relative lateral movement between the tool and the workpiece during a machining operation (= thickness of the chip) • Feed in turning and drilling • The advancement of the cutter per revolution of the workpiece (turning) or tool (drilling) • Unit - ipr (inch per revolution) • Feed in milling • The advancement of the cutter per cutter-tooth revolution • Unit - inch per revolution per tooth• Feed rate - ipm (inch per minute) • Equation (3. 17) i-Design Lab.
  19. 19. Machining• Cutting Speed • The maximum linear speed between the tool and the workpiece • Equation (3. 18)• Depth of cut • Width of the chip • Equation (3. 19)• Metal-Removal Rate • How fast material is removed from a workpiece • Equation (3. 20) ~ (3. 28) Short processing time MRR is Large ( ) Short the life of cutter i-Design Lab.
  20. 20. Machining Time• Total amount of time• Parameter • The length of the workpiece • Overtravel of the tool for clearance • The number of passes required to clear the volume• Equation (3. 29) ~ (3. 31) i-Design Lab.
  21. 21. Tool Life• Erosion (Wear) • Crater wear • High Temperature • Flank wear • Friction• Breakage (Catastrophic Failure)• F. W. Taylor • Tool-life Equation • Relation of Tool life and Cutting speed i-Design Lab.
  22. 22. Machining Force and Power Requirements• Important considerations in selecting process parameters (feed, speed, and depth of cut)• Not limiting values• Machining force • Equation (3. 35) ~ (3. 37)• Cutting power • Equation (3. 38) ~ (3. 39) i-Design Lab.
  23. 23. Process Parameters• Feed, Speed, Depth of cut• Process selection becomes an iterative procedure • Process Selection • Machining parameters are adjusted to accommodate the system constraints • Parameters affects the time and cost i-Design Lab.
  24. 24. 3.0 Introduction3.1 Experience-Based Planning3.2 Decision Tables and Decision Trees3.3 Process-Capability Analysis3.4 Basic Machining Calculations3.5 Process Optimization3.6 Conclusion i-Design Lab.
  25. 25. Process Optimization Short processing time MRR is Large ( ) Short the life of cutter• Tool has been worn → Replace• Trade-off between increased machining rate and machine idle time i-Design Lab.
  26. 26. Single-Pass Model• Assume that only one pass to produce the required geometry• The depth of cut is fixed• Constraint • Spindle-speed constraint • Feed constraint • Cutting-force constraint • Power constraint • Surface-finish constraint• Equation (3. 40) ~ (3. 47) i-Design Lab.
  27. 27. Multipass Model• Assumption of single-pass model is relaxed• Can be reconstructed into a single-pass model• The depth of cut is a control variable• Constraint • Spindle-speed constraint • Feed constraint • Cutting-force constraint • Power constraint • Surface-finish constraint • Depth-of-cut constraint• Equation (3. 63) ~ (3. 67)• No general solution method i-Design Lab.
  28. 28. 3.0 Introduction3.1 Experience-Based Planning3.2 Decision Tables and Decision Trees3.3 Process-Capability Analysis3.4 Basic Machining Calculations3.5 Process Optimization3.6 Conclusion i-Design Lab.
  29. 29. Conclusion• Information of process-planning system • Design knowledge – Chapter#2 • Process knowledge – This Chapter (Chapter#3)• Process planning • Procedure that matches the knowledge of the processes with the requirements of the design• Process Capability• Decision logic i-Design Lab.
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