%0 Conference Proceedings
%@holdercode {isadg {BR SPINPE} ibi 8JMKD3MGPCW/3DT298S}
%@usergroup administrator
%@usergroup n-mishima@aist.go.jp
%@usergroup administrator
%3 paper.pdf
%J São José dos Campos
%I Instituto Nacional de Pesquisas Espaciais (INPE)
%B ISPE International Conference on Concurrent Engineering, 14 (CE 2007).
%9 Systems Engineering
%P 47-54
%X Demands of various miniature mechanical parts and products such as for watches, cameras, medical devices, miniature die-sets, and so on, are increasing more and more. Contrarily, manufacturing systems for those parts and products are becoming larger and more complicated. The research group including the authors developed the first prototype of a microfactory which consisted of miniature machine tools and manipulators, in 2000, as a countermeasure for the situation. We insisted that the advantage of the microfactory would be its capability to reduce environmental impact and costs of manufacturing, especially for diverse-types-and-small-quantity production. Since the smallness of the each machine enables factory layout change, the microfactory can control the increase of the costs when the designs of products have been modified. By replacing conventional manufacturing systems by microfactories, electrical power and initial cost of the machines can be also reduced. On the other hand, machines of the microfactory should be designed small and simple, to ensure the abovementioned advantages. It means that those machines cannot have extra power, throughput, process capability, and so on. So, in the microfactory, many design issues such as machine design, system design and process design should be solved concurrently. And for the purpose, quantitative evaluation method for machines, systems and processes of the microfactories are required first. However, the effect of the microfactory in reducing environmental impact and costs has not been examined quantitatively. If it is possible to show how microfactory can contribute to enhance the efficiency of the production systems, application area of the microfactory will greatly expand. So, as the first step of the quantitative evaluation of system design, this paper proposes a simple efficiency index based on the overall throughput, machine cost, labor cost, electricity cost, environmental impact measured by electrical power and material consumption. The proposed efficiency index is expressed by the equation, Ef=F/SQRT(C*E), where Ef is the efficiency index, F is the functionality of the system, C is the overall cost and E is the overall environmental impact. In the paper F is simply expressed by the throughput of the system. C is the sum of the labor cost, the machine cost and the electricity cost, and E is sum of equivalent CO2 exhaust of power consumption and materials for the machines. Using the abovementioned microfactory as an example, the paper tries to examine whether the proposed index is useful in evaluating and improving the system configuration. The calculation results indicate that there are some configurations that are more efficient than the others. The calculation also shows that efficiencies of miniature systems like the microfactory are not very less than those of conventional mass production systems, when the required throughput is not very high. The result leads us to conclude that the proposed efficiency index is useful in evaluating the system design. It also insists that microfactory-like systems are hopeful for future manufacturing systems in which high functionality, low cost and low environmental impact are required.
%@session oral
%E Loureiro, Geilson,
%E Curran, Ricky,
%T Proposal of an Efficiency Index for Supporting System Configuration Design
%@electronicmailaddress n-mishima@aist.go.jp
%@electronicmailaddress k-masui@aist.go.jp
%@electronicmailaddress kondou-shinsuke@aist.go.jp
%@format Print; CD-ROM; On-line.
%K microfactory, system configuration, efficiency index, environmental impact.
%@secondarytype CI
%8 2007, July 16-20
%@e-mailaddress n-mishima@aist.go.jp
%@mark 1
%2 dpi.inpe.br/ce@80/2007/01.09.07.08.28
%@affiliation Advanced Manufacturing Research Institute, AIST, Japan
%@affiliation Advanced Manufacturing Research Institute, AIST, Japan
%@affiliation Advanced Manufacturing Research Institute, AIST, Japan
%@subject Concurrent engineering methods (e.g. DFX) and tools
%4 dpi.inpe.br/ce@80/2007/01.09.07.08
%D 2007
%1 Instituto Nacional de Pesquisas Espaciais (INPE)
%S Proceedings
%A Mishima, Nozomu,
%A Masui, Keijiro,
%A Kondo, Shinsuke,
%C São José dos Campos
%@area ETES