Surface finishing of stainless steels for orthopedic surgical tools by large-area electron beam irradiation

Okada, Akira; Uno, Yoshiyuki; McGeough, J. A.; Fujiwara, Kunihiko; Doi, Kenji; Uemura, Kensuke; Sano, Sadao

doi:10.1016/j.cirp.2008.03.062

Cited by 64 publications

(27 citation statements)

References 9 publications

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“…The EBM process applied to the A390 alloy resulted in an initial smoothing of the surface roughness with an increase in the applied energy density. However, in contrast to EBM investigations of other metal alloys [22,23], increasing energy densities caused a significant increase in the surface roughness of the A390 surfaces as a result of the formation of surface craters. Such a trend has previously been observed for steel [22,23], however, the increase in surface roughness at higher energy densities for that study was small (R z -1 lm) compared to the original surface roughness (R z -6 lm), whereas in this study the roughness at higher energy densities was greater than the original surface roughness.…”

Section: Ebm Surface Modificationmentioning

confidence: 74%

“…This causes build up of the electron density followed by a rapid discharge the power of each pulse that is sufficiently high to enable surface melting. During the time period in which the surface of the work piece becomes liquidus surface tension smoothes asperities and reduces surface roughness [22]. The key variables in the process are (i) Cathode voltage; (ii) Anode voltage; (iii) Solenoid voltage; (iv) number of shots.…”

Section: Ebm Techniquementioning

confidence: 99%

“…10b and also contained the same constituents; deformed aluminium and transferred wear debris particles from the counterface. The thickness of the surface tribo-layer was 2-3 lm, approximately the same as a metallic surface re-melted surface layer resulting from an EBM treatment [22]. …”

Section: Worn Surface Morphologymentioning

confidence: 99%

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Dry Sliding Friction and Wear Behaviour of an Electron Beam Melted Hypereutectic Al–Si Alloy

Walker¹,

Murray

Narania

et al. 2011

Tribol Lett

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The economic and environmental benefits of using light-weighting technology in automotive applications continue to attract attention for feasible commercial solutions. This study investigates the use of pulsed electron beam melting of a hypereutectic Al-Si alloy as a possible modification procedure for cylinder crankcase bore facing surfaces. Machined surfaces of an A390 alloy were subjected to five pulsed electron doses with an applied cathode potential between 16.5 and 36 kV. It was found that increasing beam accelerating voltages led to an initial decrease (1.4 lm R a ) but subsequent increase (4.0 lm R a ) in average surface roughness values associated with surface crater formation due to sub-surface melting and eruption. Surfaces were tested under dry sliding tribological conditions against 52100 bearing steel in a reciprocating geometry. Average dynamic friction coefficients were higher (0.9) compared to the untreated alloy surface (0.6) as a result of a greater degree of adhesion to the counterface. However, FIB cross sections of worn surfaces indicated that this activated an oxidative type wear process which ultimately led to the formation of a beneficial surface tribo-film on the EBM-treated surfaces, improving the specific wear rates by up to 66%.

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Section: Ebm Surface Modificationmentioning

confidence: 74%

Section: Ebm Techniquementioning

confidence: 99%

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Dry Sliding Friction and Wear Behaviour of an Electron Beam Melted Hypereutectic Al–Si Alloy

Walker¹,

Murray

Narania

et al. 2011

Tribol Lett

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“…Okada shows in his work that gloss (medium gloss, 60°) can be enhanced by the smoothing of a metallic surface and tried to correlate this result with the measured roughness Rz [18].…”

Section: Gloss Measurementmentioning

confidence: 95%

“…The analysis bases on the results of Okada who suggests an exponential correlation of gloss and roughness Rz [18]. For that purpose it is assumed that an exponential correlation between gloss and roughness like formula (1) exists.…”

Section: Correlation Of Micro Roughness and Specular Glossmentioning

confidence: 99%

Design surfaces by laser remelting

Temmler

Willenborg

Wissenbach

2015

Materialwissenschaft Werkst

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Molds and dies are used today in the manufacturing of a wide range of industrial products. They have a broad field of applications from the air and space technology, the automotive sector, to electrical engineering, to household products and consumer goods. The surface of a part or product strongly influences its properties and functions e.g. it's visual appearance. The gloss thereby reflects one of the most important properties of a surface when it comes to evaluate the visual appearance. Therefore, among others, in this paper the influence of laser polishing on the generated specular gloss is investigated for the hot work steel 1.2343 (AISI: H11). On the one hand laser polished surfaces are measured by WLI and investigated by a spectral analysis of surfaces roughness. A spectral analysis is achieved by a discrete convolution of the surface profile with a Gaussian loaded function similar to ISO 11562. On the other hand specular gloss measurements were carried out at 20°, 60° and 85°. For the experiments a fiber‐coupled solid state disc laser (Yb : YAG; Q‐switched) is used (PL,max = 550 W; repetition frequency: fP = 5–20 kHz, pulse duration: tP = 0,7–3,5 µs, pulsed and cw‐operation). In general, scanning velocity and average laser power are two crucial procedural parameters for laser polishing with significant influence on the resulting surface roughness. These procedural parameters are investigated systematically, while other procedural parameters, such as laser beam diameter dL = 250 µm and track offset dy = 25 µm were kept constant. By this a significant reduction of roughness was achieved, especially for the wavelength interval λ < 320 µm. A correlation between specular gloss of surfaces and the measured micro‐roughness is carried out. In order to make a systematic classification laser polished fields are compared to surfaces which were prepared by conventional mechanical manufacturing processes, such as turning, milling, grinding, high end manual polishing etc. Specular gloss shows a good exponential correlation with micro‐ and meso‐roughness were as macro roughness shows no significant influence on the specular gloss. Additionally, a complete process chain for selectively laser polishing of metallic surfaces was developed in order to apply different levels of gloss onto free formed work pieces. Selective laser polishing and the process chain are demonstrated for a free formed tool insert with leather textured surface, where only the indentations of the leather texture were laser polished selectively

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