Productivity improvement is one of the most challenging problem facing the motor industry. This paper deals with the lot sizing and production scheduling problems of the side frame press shop in a domestic truck manufacturing company. The problems can not be solved simultaneously due to the computational complexity. Thus, we present a heuristic method which solves the two problems sequentially with the objective of maximizing the press utilization while maintaining a minimum inventory level. A micro-computer-based software is developed for easy implementation of the heuristic in the shop floor level.

자동차 도장공장의 마지막 도색공정인 상도공정에서는 도장할 차체의 색상(Color)이 직전에 도장된 차체의 색상과 다르면 스프레이 노즐에 남아있는 직전차체의 도료\를 세정하여 하는데, 이 때 도료손실과 세정비용 등의 색상변경비용(Color Change Cost)이 발생한다. 이러한 비용을 줄이기 위하여 동일한 색상의 차체들이 가능한 한 연속으로 도장될 수 있도록, 상도공정 직적에 동일한 차체들을 모은 저장창고(Color Grouping Buffer)가 필요하다. 본 논문에서는 도장공장의 상도공정에서의 색상변경비용을 줄일 수 있도록 저장창고에서의 차체의 인입, 저장, 인출을 실시간에 제어하는 Color Selection 시스템을 자동화하여 성공적으로 운영하고 있는 사례를 소개한다.

This paper investigates the problems of grouping N products on an assembly line with an objective of maximizing the option grouping rate. Before developing a mixed model grouping algorithm, simulation studies are committed for developing operating rules and evaluating the layout production systems. A mixed model grouping algorithm is suggested and it is applied to the color selection lane in automobile production system, which reveals a high mixed model grouping rate.

자동차 조립공장의 생산은 혼류생산 (Mixed-Model Production)의 대표적인 형태로서 동일한 조립라인에서 다양한 사양의 차량들을 Batch생산이 아니라 각 사양의 생산량이 평준화되도록 생산을 하는 것이 특징이다. 그런데 도장라인에서 생산완료 된 순서는 혼류조립라에서의 평준화 생산에 적합하지 않은 상태이므로 조립라인에의 투입순서를 재작성하여 제어하여야 한다. 본 논문에서는 조립라인의 실시간 투입순서 작성 및 운영시스템을 자동화하여 성공적으로 운영한 사례를 소개하고자 한다.

자동차 조립공장의 주요 공정은 차체라인, 도장라인, 조립라인의 순으로 구성되어 있다. 작업의 효율성을 높이기 위하여 차체라인과 조립라인은 주요 부품소모의 평준화를, 도장라인은 동일 색상차체의 연속 생산을 선호하므로, 생산순서의 결정시 상호 상층되는 점이 많다. 본 연구에서는 조립공장전체의 생산성을 극대화하기 위하여 차체라인, 도장라인, 조립라인의 특성을 고려한 일일생산순서결정 방법을 제시한다.

A scheduling system is developed for a parallel machine flow shop which reflects the situations of the manufacturing processes in the tire industry. The schedule is generated via simulation using heuristic rules to get satisfaction on such constraints as due dates, demands, work-in-process, process capacity, set-up times and scheduling speed. This system, constructed with relational DB, SQL and C language, consumes less than 10 minutes of PC simulation to handle real size problems.

본 논문에서는 자동차용 전기배선 제조공정 중 절압공정을 대상으로 기계별 작업순서결정에관한 개선된 방법에 관하여 연구한다. 기계별 작업순서에 대하여 작업자들이 현장에서 느끼는 불편한 점들을 개선하려는 목적에서 연구를 진행하였음 개선된 방법을 통하여 자재교환과 치구교환횟수를 감소시킬 수 있었다. 그 결과 기계가동율이 향상되었고 계획된 작업순서에 대한 작업준수율을 높일 수 있었다.

본 논문에서, 우리는 일본제조 시스템의 대표격인 도요타 시스템을 소개하려고 한다. 도요타 시스템은 일본식 생산관리라고 하는 즉시시스템(JIT)과 전사적 품질관리(TQC)로 세계 최고의 생산성과 품질을 이룩했다. 도요타에서 JIT시스템을 성공시키기 위한 여섯 가지 기본 사항을 살펴보았다. 또한 JIT 시스템의 운영도구인 간판 시스템을 자세히 살펴봤다. 결론에선 우리나라 생산 시스템에 도요타 생산시스템이 도움이 되며, 우리나라와 일본을 비교하여, 우리도 일본 생산 시스템을 앞설 수 있음을 제시했다.

This paper presents an automated system for inspecting surface finish quality of gear teeth. The purpose of the presented system is to improve both efficiency and reliability of a gear inspection process with a lower cost. The system consists of two modules; one is for data collection and the other for data analysis. While and A/D converter is built in a PC to efficiently obtain digitized data, a window-based software for conducting quality tests is provided using VISUAL BASIC as well as C++. We successfully connect them with the existing gear tester. This system would be also useful for the gear quality improvement by means of a continuous data management.

A procedure is presented for a 3D-contour machining without cutter interferences. The 3D-contouring machining along a spatial curve is often required for manufacturing trimming and flange dies in motor industries. Input data for the machining contour is a spline curve with polynomial vector equation provided by CATIA system. Points are sampled on the contour curve and line segments and helical curves are approximated from the point data. Cutter interference is checked on the approximated spline and all of interference curves are substituted with interference-free helical curves for a tool path generation. The non-machined curve areas are locally machined by tools with smaller diameters. A tool radius offset is considered for generating NC data to be free with tool size.

Recently, the tire mold of a passenger car is made almost via aluminum casting, and it is necessary to prepare a master model of the tire for the casting. Because of the geometrical feature of tire, as well known, the master model must be machined by a 5-axis NC machine. The paper proposes a procedure to model and machine the master model. The approach includes (a) transformation of 2D drawing of tire into 3D geometry, (b) modeling surfaces of tire, and (c) inverse kinematics of a 5-axis NC machine. An implementation of the proposed procedure is also presented.

This paper deals with the development of a software module for production planning and scheduling activities of an actual die-production management system. Scheduling problems, such as master schedule and detailed schedule, are the focal point of the whole article and they are considered in terms of operation procedures. Schedule-explosion module and load levelling module are the essential components of schedule management. The scheduling module allocates the resources, determines the process priority and the planned start and completion dates of processes. Rescheduling can be done to manipulate unforeseen situations that schedule is delayed owing to inducing defectives, machine breakdowns and lumpy demands. This study indicates a practical model for the die-producation management and helps to apply it for jobs in the real situation.

In recent, most'of automobile industries adopt the concept of JIT production. According to the concept, the paternal manufacturers require their suppliers to supply parts just in time, so it is very important for a subcontractor to produce the parts in the appointed time of delivery. This study develops a production information system for Woosin Industry, which is one of such subcontractors of Hyundai Motors Company(HMC). The system is developed for use in Client/Server environment. In this study, the following three modules are developed, i. e., the production scheduling module, the sales management module to deal with the information about orders of HMC, delivery of parts, and bill collecting, and the module for supporting material requirements planning and purchase of material.

부품번호를 할당하고 관리하는 규칙은 모든 제조업체의 운용에 앞서 행해져야 하는 중요한 사항이다. 특히 완성차 제조업체의 경우 2-3만개의 부품이 사용되며, 선택사양의 다양화, 빈번한 설계변경에서의 신속한 대응, 부품확산 방지를 위해서는 효율적인 부품/모듈번호 체계가 필요하다. 본 연구는 H자동차 회사의 기존 부품번호 체계가 가지고 있는 문제점을 해결하기 위해 기존의 코드체계를 검토하여 개선방향을 정립하기 위한 것이다. 이를 위해 1) 제조업의 부품번호 체계와 관련된 이론의 수집/정리 2) 외국 완성차 업계의 번호체계 현황 조사/분석, 3) 완성차 소요부품과 관련된 코드체계의 의미를 명확화, 4) 부품번호의 균형 할당을 위한 작업이 수행되었다.

A variety of approaches on performance evaluation modeling have appeared in the technical literature for flexible manufacturing systems(FMS) which can be evaluated only through computer simulation. This study represents a comparative approach for FMS performance evaluation modeling based on reliability, availability and maintainability, and life cycle cost. The methodology proposed in this research includes the following three-step generative approaches. First, a static model to find the initial system configuration is considered under the assumption that the system availability is given as one (failure and maintenance are not considered), and in second step, a stochastic simulation is proposed to serve as a performance evaluation model for FMS with stochastic failure and repair time. In the last step, we developed a simulation modeling using a simulator, FACTOR/AIM to consider a variety of performance factors and dynamic behavior of FMS. Also the applicability and validity of the proposed approaches has been tested and compared through the results of a sample problem using computer programs and procedures developed in each step.

This paper deals with a Direct-Input-Output Manufacturing System (DIOMS) which has a number of machine centers placed along a built-in automated storage/retrieval system (AS/RS). During its operations, the storage/retrieval(S/R) machine picks up a pallet from the pickup/deposit port of a machine center and then moves it either to an empty rack opening of the AS/RS for temporary storage or to place it on the port of another machine center for subsequent operation. The machine layout problem in DIOMS is formulated as an integer mathematical programming whose objective is to minimize the total expected distance of the loaded S/R machine during a production period. Recognizing the limit of the exact solution procedure(the Branch and Bound method), two improvement-type heuristics are proposed. One is based on the simulated annealing method and the other the pairwise interchange method. The validity of the heuristics is examined with example problems.

Most studies on the operation policy for AS/RS concluded that the class-based storage policy has better performance than random storage policy does. However ASRS performances are examined only with the assumption of fixed production quantity in the studies. It is true that production quantity of each item changes frequently in practice. If an ASRS keeps the current storage policy regardless of production quantity variation, the performance of present storage policy will be worse. The effect of production quantity variation per product between 10 and 80% with random storage policy and class-based storage policy with reassignment and relocation are studied. The results are compared with both of the randomized and class-based storage policies without reassignment nor relocation cases. A typical ASRS system is developed using GPSS/PC for operation policy evaluation purposes.

Records of industrial accidents are essential to maintain efficient and successful safety programs. The objective of this study is to examine the trends of industrial accidents in manufacturing industry, based on the national statistics. From 1972 to 1994, statistics of industrial accidents were extracted from the annual publications of Ministry of Labor. The results show that there are significant characteristics and trends in the records of industrial accidents. These findings identified in this study can be used to manage the accident prevention efforts.