• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.2
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• pp.339-350
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• 1994

This paper presents a method for automatic generation of line balanced assembly sequences based on disassemblability and proposes a method of evaluating an assembly work time using neural networks. Since a line balancing problem in flexible assembly system requires a sophisticated planning method, reasoning about line balanced assembly sequences is an important field of concern for planning assembly lay-out. For the efficient inference of line balanced assembly sequences, many works have been reported on how to evaluate an assembly work time at each work station. However, most of them have some limitations in that they use cumbersome user query or approximated assembly work time data without considering assembly conditions. To overcome such criticism, this paper proposes a new approach to mathematically verify assembly conditions based on disassemblability. Based upon the results, we present a method of evaluating assembly work time using neural networks. The proposed method provides an effective means of solving the line balancing problem and gives a design guidance of planning assembly lay-out in flexible assembly application. An example study is given to illustrate the concepts and procedure of the proposed scheme.

• Journal of the Korean Wood Science and Technology
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• v.10 no.3
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• pp.118-131
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• 1982

1. In order to investigate the effect of variation of assembly time on glue bond strength, and to determine the optimum range of assembly time with given glue, this experiment was made at the suggestion of the Wood Technology Laboratory, School of Forestry, Yale University. 2. For this investigation, three-ply-plywoods with 1/22 inch, birch veneer, phenolic resin, and soybean glue were made at the following variation of assembly time, that is, 1, 5, 10, 25, 35, 50, and 70 minutes, under both open and closed assembly manners, and the shear strength test at dry and wet were adoptted. 3. The shear strength and wood failure of each plywood panel constructed at the given assembly time have been illustrated in Tables 1, 2, 3 and 4. It has shown that there is a remarkable tendency, for increasing assembly time to give lower shear strength and wood failure throughout almost all cases. The effective range of assembly time of tested glues in this investigation for both open and closed assembly are summarized in the Table 7. Thus, allowable assembly time for Phenolic resin may be up to 10 minutes under open assembly and up to 50 minutes under closed assembly. For soybean glue, the permissible assembly time may be up to 5 minutes under open assembly and up to 15 minutes under closed assembly. The allowable assembly time for open assembly with the same glue is reduced by approximately one third or more than one third as compared with closed assembly time. This might mean that the closed asembly time for these glues is more practical than the open assembly.

• Journal of Korean Institute of Industrial Engineers
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• v.33 no.3
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• pp.355-363
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• 2007

This paper presents a method of an automatic work time evaluation based on the verification of a disassemblability and assembly configuration. Even though a work time evaluation is an important field of concern for planning assembly lay-out, there are some limitations using cumbersome user query or approximated work time data without considering assembly condition. To overcome such restriction, this paper presents a method to mathematically verify assembly conditions based on the disassemblability, which is defined by the separability and stability cost. The separability cost represents a facility of the part disassembly operation, and the stability cost which represents a degree of the stability for the base assembly motion. Based upon the results, we propose a new approach of evaluating work time using neural networks. The proposed method provides an effective means of solving the work time evaluation problem and gives a design guidance of planning assembly lay-out in flexible manufacturing application. Example study is given to illustrate the concepts and procedure of the proposed schemes.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.5
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• pp.72-80
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• 2002

DFA (Design for assembly) is a design philosophy for improving product designs for simpler or less costly assembly operations. This paper proposes a new DFA methodology that can estimate the standard assembly time and evaluate the assemblablity of parts. We select some determining and influencing factors related with assembly process, and estimate the assembly time using motion analysis. By the levels of the determining and influencing factors, the assemblability is evaluated, and finally, the tables that include the time and score of assembly is suggested.

• The Journal of Korea Robotics Society
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• v.17 no.4
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• pp.455-462
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• 2022

Since electric connectors such as power connectors have a small assembly tolerance and have a complex shape, the assembly process is performed manually by workers. Especially, it is difficult to overcome the assembly error, and the assembly takes a long time due to the error correction process, which makes it difficult to automate the assembly task. To deal with this problem, a reinforcement learning-based assembly strategy using contact states was proposed to quickly perform the assembly process in an unstructured environment. This method learns to generate a search trajectory to quickly find a hole based on the contact state obtained from the force/torque data. It can also learn the stiffness needed to avoid excessive contact forces during assembly. To verify this proposed method, power connector assembly process was performed 200 times, and it was shown to have an assembly success rate of 100% in a translation error within ±4 mm and a rotation error within ±3.5°. Furthermore, it was verified that the assembly time was about 2.3 sec, including the search time of about 1 sec, which is faster than the previous methods.

• Journal of the Korea Society of Computer and Information
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• v.23 no.7
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• pp.1-10
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• 2018

In this paper, we propose the principles and design details of Automatic cable assembly test system and show its utility. Testing the cable assembly is required periodically or non-periodically in the system that the cable assembly performance is quite important like military equipment. There are several weaknesses when humans test the cable assembly manually. It not only takes much time but also could happen human error. To improve these disadvantages, I developed Automatic cable assembly test system. The system can be implemented by building switching control system that connect and disconnect the cable assembly and measuring devices. Through the result of the cable assembly test with this test system, we show this system makes test time short and improves of test reliability as compared with manual test.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.5
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• pp.72-84
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• 1998

This paper studies the relationship between assemblability and assembly time. After analyzing characteristic factors of bolts and parts, seven different kinds of assemblability parameters were determined according to assembly process, and assemblability was also evaluated. MTM (Method-Time Measurement) and Work factor methods were used for an estimation of assembly time. It shows the relationship can be found on the basis of characteristic factors of parts and bolts by relational graphs and numerical formulas.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.707-710
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• 1995

Structure of product, which is not considered by easy of assembly, has many hidden costs. For reduction of hidden costs, concepts of line balancing and assembly-oriented design are used. We find that part of structure can be improved by concept of line balancing. To reduce assembly time and enhance easy of assembly, design principles are developed by concept of assembly-oriented design. And design principles for improvement are applied according to condition of the grasped parts of product structure. Thersfore, we could design assembly-oriented design for better structure and low cost.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.7 s.196
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• pp.39-48
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• 2007

This paper presents a method of a line balanced assembly sequence generation based on the verification of a disassemblability and a work time. To derive the disassemblability for a part to be disassembled, first we inference collision free assembly directions by extracting separable directions fur the part. And we determine the disassemblability defined by the separability and stability cost. The separability cost represents a facility of the part disassembly operation, and the stability cost which represents a degree of the stability for the base assembly motion. Based upon the results, we propose a new approach of evaluating work time using neural networks. The proposed assembly sequence generation provides an effective means of solving the line balancing problem and gives a design guidance of planning assembly lay-out in flexible manufacturing application. Example study is given to illustrate the concepts and procedure of the proposed schemes.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.6
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• pp.151-159
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• 2003

This paper presents a new DFA methodology to estimate the standard assembly time and evaluate the assemblablity of a product. The assembly time is estimated with some decision and influencing factors of assembly using motion analysis. The assemblability is evaluated using weights of the decision and influencing factors and assembly difficulty scores, and the tables that include the time and score of assembly are suggested. Finally, a new DFA system supporting the DFA is implemented to help designers to analyze the product during the design process in concurrent engineering.