Surface Finish and Back-Wall Dross Behavior during the Fiber Laser Cutting of AZ31 Magnesium Alloy

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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Fiber laser cutting of AZ31 magnesium alloy: numerical and experimental investigation

10.1117/12.2203050 ◽

2015 ◽

Author(s):

Huafeng Guo ◽

Juli Li ◽

Min He ◽

Xiao Wu ◽

Tao Sun

Keyword(s):

Experimental Investigation ◽

Magnesium Alloy ◽

Fiber Laser ◽

Laser Cutting ◽

Az31 Magnesium Alloy

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Formability of AZ31 Magnesium Alloy Sheet in Dry Press Forming Using Diamond-Coated Dies

Volume 4: Design and Manufacturing ◽

10.1115/imece2009-10957 ◽

2009 ◽

Author(s):

S. Tsuda ◽

S. Yoshihara ◽

S. Kataoka

Keyword(s):

Surface Roughness ◽

Magnesium Alloy ◽

Magnesium Alloys ◽

Deep Drawing ◽

Chemical Vapor ◽

Alloy Sheet ◽

Az31 Magnesium Alloy ◽

Specific Strength ◽

Press Forming ◽

Forming Tools

Dry press forming which hasn’t used lubricants in the process is the attractive forming technique of zero emission for the lubricants. As one of the dry press forming techniques, the usage of dies coated with a chemical vapor deposition (CVD) diamond film, which are expected to be applied to forming tools owing to their high tribological properties, abrasion resistance and heat resistance, has been proposed. Magnesium alloys have attracted attention owing to their advantages over what such as, high specific strength and ease of recycling. However, they have intractable characteristics, and it is necessary to perform the forming technique at high temperature and to consider lubrication condition. In this study, diamond-coated dies were used in the deformation of magnesium alloy sheets without lubricants in press forming, and the formability of magnesium alloy and its effect on the surface texture of a formed-cup were investigated. Dry deep-drawing tests and dry ironing tests were carried out to estimate the effect of the diamond-coated dies on the formability of magnesium alloy sheets. Furthermore, the formability obtained using the above-mentioned tests was compared with that obtained in tests using non-lubricant dies with traditional lubricant. AZ31 magnesium alloy sheets (thickness: t0 = 0.5 mm) were deformed at 200 °C in dry deep-drawing tests. From the results, it was found that what can be deformed using diamond-coated dies. Moreover, a 20% reduction in drawing force was confirmed compared with the usage of the traditional lubricant (MoS2). Meanwhile, dry ironing tests were performed under conditions of 10% ironing ratio by a method similar to the dry deep-drawing tests. In general, the ironing process, which is the most difficult step in lubrication in sheet forming, has been enabled by the diamond coating technique. Furthermore, it was observed that the surface roughness of the formed-cup walls using the diamond-coated dies was 0.4 μmRz, and, 1.3 μmRz in case of MoS2. It was confirmed that the application of diamond-coated dies improved the surface roughness of the formed-cup. It produced an improvement in the formability of magnesium alloys compared with the traditional lubrication technique (use of MoS2). It was concluded that the validity of the use of diamond-coated dies became clear.

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