Experimental Study of Back Wall Dross and Surface Roughness in Fiber Laser Microcutting of 316L Miniature Tubes

Magnesium alloys are of increasing interest in the medical industry due to their biodegradability properties and better mechanical properties as compared to biodegradable polymers. Fiber laser cutting of AZ31 magnesium alloy tubes was carried out to study the effect of cutting conditions on wall surface roughness and back-wall dross. During the experiments, an argon gas chamber was adapted in order to avoid material reactivity with oxygen and thus better control the part quality. A surface response methodology was applied to identify the significance of pulse overlapping and pulse energy. Our results indicate minimum values of surface roughness (Ra < 0.7 μm) when the spot overlapping is higher than 50%. A back-wall dross range of 0.24% to 0.94% was established. In addition, a reduction in back-wall dross accumulations was obtained after blowing away the dross particles from inside the tube using an argon gas jet, reaching values of 0.21%. Laser cutting experimental models show a quadratic model for back-wall dross related with the interaction of the pulse energy, and a linear model dependent on pulse overlapping factor for surface roughness.

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An Experimental Study of Surface Roughness Effects on Turbulent Boundary Layer Flow and Heat Transfer

10.21236/ada212099 ◽

1989 ◽

Cited By ~ 5

Author(s):

Hugh W. Coleman ◽

Robert P. Taylor ◽

M. H. Hosni ◽

Glenn B. Brown ◽

Philip H. Love

Keyword(s):

Heat Transfer ◽

Boundary Layer ◽

Experimental Study ◽

Surface Roughness ◽

Turbulent Boundary Layer ◽

Boundary Layer Flow ◽

Roughness Effects ◽

Flow And Heat Transfer ◽

Turbulent Boundary Layer Flow ◽

Layer Flow

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Experimental study on transverse-mode controlling with coated concave mirror for large-mode-area fiber laser

Optik ◽

10.1016/j.ijleo.2013.02.023 ◽

2013 ◽

Vol 124 (18) ◽

pp. 3723-3725

Author(s):

Dong Xue ◽

Yang Liu

Keyword(s):

Experimental Study ◽

Fiber Laser ◽

Transverse Mode ◽

Concave Mirror ◽

Large Mode Area ◽

Mode Area

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Experimental Study on Roughness Effect for Laminar Micro-Channel Gas Flow

10.1115/imece2001/mems-23866 ◽

2001 ◽

Author(s):

Jih-Hsing Tu ◽

Fangang Tseng ◽

Ching-Chang Chieng

Keyword(s):

Experimental Study ◽

Surface Roughness ◽

Friction Factor ◽

Gas Flow ◽

Micro Channel ◽

Micro Machining ◽

Roughness Effect ◽

Relative Roughness ◽

Smooth Channel ◽

Micro Channels

Abstract Present study investigates the roughness effect on laminar gas flow for microchannels ranging from 40 to 600 μm with various roughness heights (40–82 nm) by systematical experiments. The micro-channels are manufactured by micro-machining technology and KOH anisotropic etching is employed to achieve various roughness patterns. Experimental results shows that higher product levels of Reynolds number (Reh) and friction factor (f) are obtained for microchannels of larger size and smaller relative roughness and friction factor f approaches to laminar flow theory value f0 for very smooth channel but the ratio of (f/f0) decreases as the surface roughness increases.

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Effect of Tightening Speed on the Torque-Tension and Wear Pattern in Bolted Connections

Volume 2: Computer Technology ◽

10.1115/pvp2006-icpvt-11-93211 ◽

2006 ◽

Cited By ~ 2

Author(s):

Sayed A. Nassar ◽

Ramanathan M. Ranganathan ◽

Saravanan Ganeshmurthy ◽

Gary C. Barber

Keyword(s):

Experimental Data ◽

Experimental Study ◽

Surface Roughness ◽

Initial Level ◽

Zinc Coating ◽

Optical Microscope ◽

Wear Pattern ◽

Highly Sensitive ◽

Contact Surfaces ◽

Scanning Electron

This experimental study investigates the effect of tightening speed and coating on both the torque – tension relationship and wear pattern in threaded fastener applications. The fastener torque – tension relationship is highly sensitive to normal variations in the coefficients of friction between threads and between the turning head and the surface of the joint. Hence, the initial level of the joint clamp load and the overall integrity and reliability of a bolted assembly is significantly influenced by the friction coefficients. The effect of repeated tightening and loosening is also investigated using M12, Class 8.8, fasteners with and without zinc coating. The torque – tension relationship is examined in terms of the non-dimensional nut factor K. The wear pattern is examined by monitoring the changes in surface roughness using a WYKO optical profiler and by using a LECO optical microscope. A Hitachi S-3200N Scanning Electron Microscope (SEM) is used to examine the contact surfaces, under the fastener head, after each tightening/loosening cycle. Experimental data on the effect of variables and the tightening speed, fastener coating and repeated tightening on the nut factor are presented and analyzed for M8 and M12, class 8.8, fasteners.

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