Nitinol, a shape memory alloy (SMA), is manufactured from titanium and nickel, and is employed in various fields for use in devices such as micro sensors, ultra-precision devices and satellite wings. It is also highly recommended as a material in medical stents for insertion into the human body because it has excellent organic compatibility. However, because they are intended to be inserted into the human body, products such as medical stents require a high-quality surface. Because nitinol has more of the characteristics of titanium than of nickel, one of its drawbacks is that heat generated in nitinol during machining is not discharged smoothly and inner stress occurs when traditional machining methods are used. To overcome this difficulty, various non-traditional machining methods, including non-contact machining, have been investigated for use with nitinol. To further explore non-traditional machining methods that may be appropriate for use with nitinol, this study investigates the application of electrochemical polishing to the machining of nitinol. Characteristics of the electrochemical polishing (EP), a representative non-traditional machining, for nitinol SMA are studied. Nitinol SMA of the EP machining parameters such as electrolyte composition, applied current, machining time and inter electrode gap (IEG) are researched and the machined surface state is analyzed according to each parameters parameter. So, the most suitable EP machining conditions for nitinol SMA are derived.
The perceived attractive female figure in Asia has moved toward the universally accepted ideal WHR. However, there were still some differences between Asian and Western societies in the concept of ideal body figure. Also, a significant difference in body contour was observed between normal women and the ideal figure. This is because hip volume decreases and waist volume increases with age, although waist and hip volumes increase with BMI.
Prospects of Y 2 O 3 have been more extended as a great promising and creditable material for optical, electronic and mechanical purposes. Y 2 O 3 has been more observed as a fine ceramic which has great material properties: high light transparency, excellent thermal resistance and chemical inertness. But in terms of effective application of Y 2 O 3 , its hard and brittle nature needs to be overcome during the surface machining process. Therefore, the surface machining control of Y 2 O 3 should be conducted carefully. The evaluation for stable and continuous machining should also be investigated in various industrial fields as there are only limited studies on the subject. The lapping process with in-process electrolytic dressing (IED) is widely used for surface machining of hard and brittle materials. In this study, Y 2 O 3 surface machinability was evaluated by using the ultra-precision lapping process with IED method by changing three major variables: applied force, wheel speed and machining time. The most suitable value of Ra 92nm surface roughness was acquired with smooth surface quality from the following machining condition: 7kg of applied force, 60rpm of wheel speed and 30minutes of machining time. After the lapping process, the machining tendency and surface characteristics were analyzed with fracture toughness and Vickers hardness for the evaluation of Y 2 O 3 surface machinability.
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