Modelling, simulation and optimisation of the technological processes of assembly

Technological processes of manual and robotic assembly are becoming an increasingly important issue in todays competitive market. Therefore, effec- tive methods and models for their implementation should be investigated. Solving problems related to the most cost-consuming and labor-intensive part of the production process, which is assembly, must be subject to con- stant development and optimization. On the other hand, in this part of the process one can find the greatest reserves enabling the improvement and increase of production efficiency. In this monograph, an attempt was made to compensate for selected and varied assembly processes, based on real practical examples concerning eg. algorithms for recording structures and optimization of assembly planning processes. The methods and systems presented in this study illustrate the main, selected trends that have re- cently become visible in the design and improvement of assembly process- es. The algorithms and heuristics described in this monograph can be used, in most cases in manual and computer aided assembly planning.

 

Table of contents

Definitions and symbols 7

1. Introduction 10

2. Technological process of assembly 13

2.1. Role and importance of assembly in the technical preparation of production 14

2.2. Designing the technological assembly process 17

2.3. Integrated assembly model 21

2.4. Automation and robotisation of the technological process of assembly 22

2.5. Assembly sequence planning 25

2.6. Conclusions 35

3. Assembly sequence planning with a directed hypergraph, digraph,
state matrix and graph 38

3.1. Introduction 38

3.2. Base Part Selection 39

3.3. From hypergraph to directed graph 42

3.4. Matrix representation of the design 44

3.5. Assessment of transitions between assembly states 46

3.6. Selection of the extreme path in a directed graph 48

3.7. Example of an algorithm for ASP 51

3.8. Determining the assembly sequence with the use of the Msassembly software 54

3.9. An example of a flexible robotic assembly system 59

3.10. Assumptions for a flexible robotic assembly system 59

3.11. Assembly unit identification system 62

3.12. Generation of assembly sequences feasible in terms of design constraints 64

3.13. Assembly sequence assessment 66

3.14. Conclusions 67

4. Example of modelling and simulation of the technological process
of assembly of a machining centre 68

4.1. Introduction 68

4.2. Measurements of labour input required for individual operations 69

4.2.1. Timing stages 69

4.3. Stages of conducting a working day activity study 72

4.4. The technological process of assembly of the machining centre 74

4.5. CAD simulation 75

4.5.1. Introduction 75

4.5.2. CAD System 76

4.5.3. Modelling assemblies (products) 76

4.5.4. Presentation and documentation of assembly 79

4.6 Balancing the final assembly line of the machining centre 81

4.7 Modelling and simulation of the technological process of assembly
of a machining centre 88

4.8 Development of work regulations, methods of communication and the
algorithm of the functioning of the information and diagnostic system as
part of the active control and supervision of operation of the assembly line 93

4.8.1. Assumptions 93

4.8.2. System structure 95

4.8.3. System operation 97

4.9 Simulation tests of the information and diagnostic system and the
technological process of assembly of the machining centre; adopting
the final structure 109

4.9.1. Simulation tests of the information and diagnostic system and the
 technological process of assembly of the machining centre 109

4.9.2. Conclusions 117

5. Modelling and simulation of the technological assembly process,
taking into account MTBF 119

5.1. Mean Time Between Failures – MTBF 119

5.2. The process of assembling the dashboard to the car body 120

5.3. Modelling and simulation of the assembly cell for assembling the dashboard to the car body 121

5.4. Conclusions 124

6. Examination of the efficiency of the assembly cell for the assembly
of the main spindle to the turning centre 126

6.1. Assembly technology of the main headstock 126

6.2. Examination of the labour input required for the assembly operations 127

6.3. Operation sequence 128

6.4. Modelling and simulation of the assembly cell 128

6.5. Conclusions 131

7. Summary and conclusions 135

References 137