Toshijiro Ohashi

Assembly Reliability Evaluation Method (AREM)

Abstract This paper proposes a new design system for assembly quality evaluation called AREM. It is based on the assembly fault occurrence model reflecting both product design and assembly shops. It prevents faults in assembly shops related to the design of the product. The system has three distinctive features: estimation of faults caused by design, extraction of faulty parts or faulty operations, and analysis of fault phenomena. AREM can distinguish the responsibility of the design and the shop quantitatively. This method is being used for various products in practical production lines, and has proven to be effective.

Recyclability evaluation method (REM) and its applications

Realization of successful recycling of end-of-life products greatly depends on, as well as environmentally conscious, whether the recycling process can be made economically feasible. We regard the ease of product recycling as indispensable in order to realize a feasible recycling process. In order to make products easier to recycle, it is necessary to take the ease of disassembly processing and final treatment into consideration at the design stage. Therefore, an advanced evaluation method that can evaluate a products ease of recycling, with minimal prototyping and testing of the product is required at the early design stage. In answer to this, we have developed the Recyclability Evaluation Method (REM). In this paper, the theory of the method, procedure and the structure of the system are presented and a number of application examples are given.

Development of machining-producibility evaluation method (MEM)

The Machining-producibility Evaluation Method (MEM) was developed to assess design quality for easier processing of parts and products. It has been effectively used in the Hitachi Group and other companies. MEM covers cutting (turning) and grinding, sheet metal working, welding, molding, die casting, and casting. It features: 1. Quantitative evaluation using easy to understand 100 point evaluation scale and estimated processing cost index. 2. Method is easy to both learn and use. Using approximately 20 basic symbols. 3. Concurrent calculation of processing cost for workshop with indices.

Recyclability Evaluation Method

Realization of successful recycling of end-of-life products greatly depends on, as well as environmentally conscious, whether the recycling process can be made economically feasible. We regard the ease of product recycling as indispensable in order to realize a feasible recycling process. In order to make products easier to recycle, it is necessary to take the ease of disassembly, processing and final treatment into consideration at the design stage. Therefore, an advanced evaluation method that can evaluate a product’s ease of recycling, with minimal prototyping and testing of the product is required at the early design stage. In answer to this, we have developed the Recyclability Evaluation Method (REM). In this paper, the theory of the method, procedure and the structure of the system are presented and a number of application examples are given.Copyright

Automatic assembly line for VTR mechanisms

An automatic assembly line for VTR mechanisms was developed. The line, 88% of the stations on which are automated, consists of 56 dedicated automatic assembly machine stations, 11 robot stations, and 9 manual assembly stations. Prior to development of the line, the product design was reviewed by using the Hitachi Assemblability Evaluation Method. System design was carried out effectively with the help of computer simulation. The installation of robots and modularized, standardized stations provided line flexibility. The robots are used for delicate and precise subassemblies of complicated shape. Development of this line reduced assembly labor to 1/6th, the necessary assembly shop area to 1/3rd, and the readjustment rate of the final assemblies to 1/5th upon line completion. Performance has subsequently been doubled.

AREM Shop Evaluation Method

Abstract A new tool has been developed to evaluate the reliability of assembly shop operation. It is a subsystem of AREM (Assembly Reliability Evaluation Method) [1] that can evaluate assembly fault occurrence rates by using product design information. This new tool uses approximately forty questions to assess quantitatively the influence of assembly shop operation reliability on assembly fault occurrence. This method is being used both to improve shop operation reliability and to select preferable shop, and is proven to be effective. The entire AREM system supports efficiently systematic improvement in assembly quality by examining both product design and assembly shop.

Assembly reliability evaluation method (AREM)

This paper introduces an effective new design-for-quality tool called AREM that visualizes assembly fault potential. Its evaluation formula is constructed on a fault occurrence model and enables quantitative evaluation of the fault generation potential of both product and assembly shop. The distinctive features of AREM are:(1) visualization of parts and operations having a high fault probability detection capability; (2) easy input by symbol selection as well as simultaneous assemblability evaluation; and (3) shop reliability, as well as product reliability, can be evaluated quantitatively. The method can be integrated with other DFX tools such as the assemblability evaluation method (AEM), and the recyclability/disassemblability evaluation method (REM/DEM) to realize a comprehensive production design evaluation system.

Ecological information system-data exchange system between manufacturers and recyclers

In order to realize a sustainable society, economically feasible recycling is essential. Such a system requires effective utilization of product and recycling process information for environmentally conscious product design and efficient, high quality recycling. A prototype of an ecological information system that enables information exchange between manufacturers and recyclers has been developed. Basic functions have been examined and future objectives for practical installation are being discussed.

Study on TV recyclability

Due to the depletion of natural resources, the shortage of dumping sites and the environmental pollution caused by hazardous chemical substances, there is a growing demand for the recycling of discarded products. The electrical home appliance industry has continued its efforts to develop easy-to-recycle products. In order to recognize the effects of these improvements and to identify subjects for future design for recycling (DFR), this study measures and analyzes the disassembly time and recycleability of TV sets. The results show that disassembly time is reduced by 6-20%, while recycleability improves by 20-25% for medium-size and larger TV sets. This illustrates the desirability of conducting DFR for TV sets, and highlights its effectiveness for preserving the environment.