Since Karl Benz built the first motor driven vehicle in 1886 a new industry was born which is still one of the most important and influential sectors of economy. His 0.9 horse-power engine only reached 15 kilometers per hour but gave the starting shot for more and more inventions and a rapidly growing automobile industry. First cars where used for racing only but during the first period of the twentieth century it established its position as a new and individual means of transport. In 1936 the first Volkswagen called Beetle, a vehicle for the masses, was developed by Ferdinand Porsche and has been produced for 67 years. The last Beetle was built in the summer of 2003 in Mexico. Worldwide 100.000 new cars are being produced every day and in 2010 there will be over 1 billion private cars all over the world. This development requires perfectly organized and well optimized production processes and still calls for new inventions and improvements.
The production process in automobile manufacturing splits into three major stages. The moulding and welding of the car body in the body shop, the painting of the welded car bodies in the paint shop and the customization of the painted car bodies in the assembly shop.
The work presented here deals with the last two stages. The production plant contains a system of production lines which sometimes split into parallel lines and reunite to a non-parallel line. Each of these lines can require some set of restrictions on the cars sequenced on that line.
In the paint shop the cars are being painted on a line by a robot which through jets sprays the color onto the surface of the car body. Whenever the next car on the line has the same color the jets can be re-used. Otherwise they have to be cleaned which requires time and causes pollution. Therefore, minimizing the color changes that occur in the paint shop can save non negligible costs.
In the assembly shop separate teams install different options into the cars such as sun-roof, air-conditioning, central locking system etc. Therefore the order of the cars on the line has to fulfill some restrictions considering that each option requires a fixed time for installation and resources which have to be available at the time of installation.
Inhaltsverzeichnis (Table of Contents)
- Introduction.
- Problem Formulation and Simplification
- Simplification
- Splitting the Problem.
- History of the Subproblems
- Structure of this Work
- Notations
- Assembly Line Balancing.
- Objectives on Leveled Words.
- A Simplified Problem: Maximum Deviation Just-In-Time Scheduling
- A Model and an Integer Program
- Complexity Results
- NP-complete Cases
- Polynomial Cases
- Solution Approaches
- Exact Approaches.
- Heuristic Approaches
- Reduction of Color Changes.
- Previous Work
- Weak Balance of a Sequence
- A Model and an Integer Program
- Solution Approaches
- Exact Approaches.
- Heuristic Approaches
- Combining the Subproblems with the Buffer
- Theoretical Background
- Re-sorting the Paint Shop Sequence to an Assembly Sequence
- Re-sorting an Assembly Sequence to a Paint Shop Sequence
- Computational Results
- DISTANCE CONSTRAINED BALANCING
- WEAKLY BALANCED COLOR REDUCTION
- PS2AL versus AL2PS.
- Returning to Practice
- Basic Concepts
- Plant Layout
- Routing Patterns
- Rules.
- Sequence Construction
- Clustering into Slots
- Suggestions for Real World Production Plants
- Conclusions
Zielsetzung und Themenschwerpunkte (Objectives and Key Themes)
This work focuses on optimizing the production process in automobile manufacturing, specifically addressing the challenges of sequencing and sorting in just-in-time production. The primary aim is to improve efficiency by minimizing color changes in the paint shop while simultaneously ensuring the fulfillment of assembly shop requirements.
- Assembly line balancing and scheduling
- Color change reduction in the paint shop
- Buffer optimization for re-sorting car sequences
- Analysis of complexity and solution approaches for the subproblems
- Application of theoretical concepts to real-world production plants
Zusammenfassung der Kapitel (Chapter Summaries)
- Introduction: This chapter introduces the problem of sequencing and sorting in just-in-time production in the context of automobile manufacturing. It describes the different stages of production, including the body shop, paint shop, and assembly shop, and highlights the importance of minimizing color changes in the paint shop while meeting assembly shop requirements. The concept of a buffer as a re-sorting mechanism between the paint shop and assembly shop is introduced.
- Assembly Line Balancing: This chapter delves into the problem of assembly line balancing, specifically focusing on maximizing the deviation just-in-time scheduling. It presents a simplified model, an integer program, and analyzes the complexity of the problem. Different solution approaches, including exact and heuristic methods, are discussed.
- Reduction of Color Changes: This chapter focuses on minimizing color changes in the paint shop. It explores previous work on this topic, defines the concept of weak balance of a sequence, and presents a model and an integer program for the problem. Solution approaches, including exact and heuristic methods, are discussed.
- Combining the Subproblems with the Buffer: This chapter explores the capabilities of the buffer as a re-sorting mechanism. It provides a theoretical background, discusses the re-sorting processes from the paint shop to the assembly shop and vice versa, and combines the solution strategies from the previous chapters to address the overall problem.
- Computational Results: This chapter presents computational results for the different subproblems, including distance constrained balancing, weakly balanced color reduction, and comparisons between different re-sorting strategies.
- Returning to Practice: This chapter focuses on practical aspects of applying the theoretical concepts to real-world production plants. It covers basic concepts like plant layout, routing patterns, and rules, and discusses how to implement sequence construction and clustering in real-world scenarios. The chapter concludes with suggestions for optimizing production processes in real-world production plants.
Schlüsselwörter (Keywords)
Just-in-time production, assembly line balancing, color change reduction, buffer optimization, re-sorting, complexity analysis, solution approaches, computational results, plant layout, routing patterns, real-world applications.
- Quote paper
- Robert Nickel (Author), 2004, Sequencing and Sorting in Just-In-Time Production, Munich, GRIN Verlag, https://www.grin.com/document/36806