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Volume 40, Issue 6
Displaying 1-8 of 8 articles from this issue
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Masanori YOSHIKAWA1997 Volume 40 Issue 6 Pages 505-510
Published: June 20, 1997
Released on J-STAGE: October 20, 2009
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IntroductionMichio MINATO1997 Volume 40 Issue 6 Pages 511-512
Published: June 20, 1997
Released on J-STAGE: October 20, 2009
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A Modified Structure of the Surface by Polishing and H2, H2O-DesorptionTeiichi HOMMA, Shuji AKIYA, Tomohiro SUZUKI, Michio MINATO1997 Volume 40 Issue 6 Pages 513-517
Published: June 20, 1997
Released on J-STAGE: October 20, 2009
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Shunichi SATO, Kouki SHIMIZU1997 Volume 40 Issue 6 Pages 518-522
Published: June 20, 1997
Released on J-STAGE: October 20, 2009
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Koichi SEIMIYA1997 Volume 40 Issue 6 Pages 523-528
Published: June 20, 1997
Released on J-STAGE: October 20, 2009
JOURNAL FREE ACCESSElectroabrasive polishing is applied to the inner surfaces of SUS316L pipes of about 4 mm in diameter and 35 mm in length. The surface roughness of the drawn BA pipes is improved from about 3 μm Rmax before polishing to 0.05 μm Rmax. In the rough, intermediate and final stages of polishing, the tool electrode with #500 and #3000 nylon fabric sheets and a urethane sheet, respectivaly, was used, each with working times of 2 minutes at a current density of 0.20.3 A/ cm2. The surface roughness obtained through this process is one-tenth or less than that by the electropolishing process currently used for long stainless steel pipes of 4 meters in length. The tool electrode is not only rotated at 23 rps but also reciprocated at 7 Hz with an amplitude of 8 mm in order to obtain an abrasive grain crossing angle sufficient to avoid circular scratches. Characteristics of the electroabrasive polishing process are compared between machined pipes and drawn BA pipes. The removal rate for the former is approximately twice that of the latter at 0.3 A/cm2. The upper limit of current density for a mirror-finished surface is much higher in the former. These experimental findings can be attributed to the existence of the hardened surface layer formed by a bright annealing process. A trial electroabrasive polishing machine for long pipes 1 m in length is produced, and experiments are carried out to obtain useful data for putting the machine into practical use.View full abstractDownload PDF (962K) -
Junji SHIBATA, Tamotsu MIYAZAKI1997 Volume 40 Issue 6 Pages 529-534
Published: June 20, 1997
Released on J-STAGE: October 20, 2009
JOURNAL FREE ACCESSVacuum technology currently plays a major role not only in academic scientific fields, but also in practical industrial fields. In order to further progress vacuum technology, we cannot avoid the problems of outgassing from the inner wall of apparatus which must be finished with a mirror surface mainly by various abrasive processes. Outgassing is considered to be affected by the surface characteristics, however, the relation of outgassing to the surface characteristics has not been investigated sufficiently from a technological point of view. Therefore, in this study, we considered the micro topography of the surface and attempted to investigate the relationship between the outgassing rate and the surface roughness of aluminum work surfaces in a high vacuum range. The work surfaces were finished with several kinds of roughness by belt-grinding and other processes. As a result, it was found experimentally that the outgassing ratehad a close correlation to the surface roughness which is estimated by the roughness factor, RF, (real work surface area/nominal work surface area). Finally, it is concluded that we should consider the surface characteristics from the molecular point of view (micro-roughness) in order to estimate the outgassing.View full abstractDownload PDF (1331K) -
Keisuke TAJIRI, Zensaburo KABEYA1997 Volume 40 Issue 6 Pages 535-540
Published: June 20, 1997
Released on J-STAGE: October 20, 2009
JOURNAL FREE ACCESSWe developed electropolishing process of aluminum using vibrating blade agitator that can provide pit-free surface. The vibrating blade agitator is such an agitator that has blades vertically attached to an axis vibrating up and down at dozens of cycles a second.
Pitting is caused by hydrogen gas bubbles generated at cathode during electropolishing. Those bubbles often stick on the parts' surface and make pits there. They stick more heavily when larger plane parts are electropolished in viscous electrolytes.
We electropolished aluminum gasket for linear accelerator. The gasket is 135 mm in diameter, 2 mm thick and has some holes. Pulsating stream produced by vibrating blades kept hydrogen gas bubbles away from the gasket and avoided them sticking on the surface during electropolishing.
Polished surface was highly smooth and pit-free. Surface roughness was diminished from Ra= 0.09 μm to Ra=0.03 μm, and oxide layer of 200 nm thick was formed on the surface after electropolishing.View full abstractDownload PDF (1206K) -
Yuichi OKAZAKI1997 Volume 40 Issue 6 Pages 541-545
Published: June 20, 1997
Released on J-STAGE: October 20, 2009
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