Holding time in the pressing cycle and its influence on the performance characteristics of zinc oxide varistor discs

Karim, A.N. Mustafizul and Puyane, R. and El-Baradie, M.A and Hashmi, M. S. J. (1998) Holding time in the pressing cycle and its influence on the performance characteristics of zinc oxide varistor discs. Journal of Materials Processing Technology, 77. pp. 54-58. ISSN 0924-0136

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Abstract

The pressing cycle usually adopted for compacting zinc oxide varistor discs is similar to that followed in the case of conventional ceramic processing. The approach consists of applying force through punches on the powder within the die,employing a number of holding or dwell times in the different phases of loading. Depending on the frictional surface area and the volume of the disc, the total duration of the holding time can be about 20–30% of the pressing cycle. Although there are some specific purposes of these dwell times in obtaining the desired quality of the green body, the resultant effect on the sintered physical and electrical property of the varistor is not reported. The present study was conducted to investigate the impact of the holding time on the performance characteristics. Three input variables, pre-press, press dwell and ejection delay time, were varied at two levels to undertake a factorial design for evaluating the main and interactive effects of these parameters. It has been observed that these dwell times have considerable influences on the physical as well as on the electrical properties of the varistor discs. Thus there is scope for optimizing the level of these pressing parameters to secure enhanced varistor performance.

Item Type:	Article (Journal)
Additional Information:	4289/26848
Subjects:	T Technology > T Technology (General) > T55.4 Industrial engineering.Management engineering. > T58.7 Production capacity. Manufacturing capacity
Kulliyyahs/Centres/Divisions/Institutes (Can select more than one option. Press CONTROL button):	Kulliyyah of Engineering > Department of Manufacturing and Materials Engineering
Depositing User:	Prof. Dr. A. N. Mustafizul Karim
Date Deposited:	24 Jul 2013 10:20
Last Modified:	24 Jul 2013 10:20
URI:	http://irep.iium.edu.my/id/eprint/26848

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