Design and fabrication of a novel 4D-printed customized hand orthosis to treat cerebral palsy.

This research study is dedicated to additive manufacturing of the shape memory polymer hand orthosis to treat patients with cerebral palsy. The treatment process for cerebral palsy is a step-by-step process that needs different adjustments for the spastic hand to stretch it towards a normal posture, whereas meeting these requirements using conventional methods or complicated mechanisms is expensive, less flexible, time-consuming, and less practical. A comprehensive investigation was conducted to design and fabricate novel thermally actuated customized hand orthosis via digital light processing (DLP). The highly precise scanning device was used to derive the hand model, and subsequently, the Blender software was used to design the customized orthosis. The results showed that fabricated orthosis could represent a strong potential to become an alternative treatment for cerebral palsy. The shape memory actuation of the orthosis indicated that 100 % shape recovery is achievable in different actuating conditions with recovery temperatures higher than 55°C. Besides, it was found that the response time and shape recovery percentage could be tailored in the range of 5 to 40 s and 45 to 100%, respectively, by adjusting programming and actuation temperatures. Further, the repeatability of the shape memory effects in the printed orthosis was investigated as well, which proved that until 17 repetitions, 100 % shape recovery was achievable.

Experimental Study of the Surface Quality of Form-Cutting Tools Manufactured via Wire Electrical Discharge Machining Using Different Process Parameters.

Form-cutting tools are an economical choice for turning parts with defined profiles in mass production. The effects of the form contour of these tools-produced by the wire electrical discharge machining (WEDM) process-on tool quality were investigated in this research. This study focuses on reducing the adverse effects of the recast layer induced by WEDM on form-cutting tools. The basic component types of profile forms in form-cutting tools can be summarized by a combination of four modes, i.e., concave and convex arcs and flat and oblique surfaces. Hence, sample cutting tools with three different radii of convex and concave arcs and a flat surface were produced. During the WEDM operation, one-pass mode was used for roughing, two passes for semi-finishing, and three passes for finishing. Furthermore, the difference between the percentage of oxygen and carbon elements on the recast layer in the two areas above the workpiece or wire entry point and the bottom area of the workpiece or wire exit point was investigated. Finally, the influences of the direction, size of the curvature, and the number of passes in the wire electric discharge process on the recast layer were analyzed. It was observed that the recast layer thickness could be reduced by increasing the number of WEDM process. Additionally, the uniformity of the cutting contour was superior in the entry region of the wire going into the workpiece compared with the exit region of the wire.

Experimental Investigation of the Effects of Machining Parameters on the Performance of Form-Cutting Tools Manufactured by Wire Electrical Discharge Machining (WEDM) and Grinding Processes.

In this research, a comparison between two methods of grinding and WEDM and the chip formation of each form tool was studied through a set of designs of experiments. A multi-functional form tool with different cutting-edge shapes was designed to compare different production methods, and a grinding machine and a five-axis wire-cutting machine were made. The form tools by the wire cutting method were made with three different machining states, rough, semi-finish, and finish. The results of the experimental test showed that the chip formation of the finished surface of the wire cut tool was close to the ground tools. Additionally, the tool life in wear generation was assessed, revealing that the tool generated through the wire-cutting method with three passes exhibited superior performance compared to alternative approaches. Furthermore, employing the wire-cutting technique with high surface finishing yielded optimal outcomes for producing form-cutting tools featuring complex profiles.

Effects of high power ultrasonic vibration on temperature distribution of workpiece in dry creep feed up grinding.

Temperature history and distribution of steel workpiece (X20Cr13) was measured by a high tech infrared camera under ultrasonic assisted dry creep feed up grinding. For this purpose, a special experimental setup was designed and fabricated to vibrate only workpiece along two directions by a high power ultrasonic transducer. In this study, ultrasonic effects with respect to grinding parameters including depth of cut (ae), feed speed (vw), and cutting speed (vs) has been investigated. The results indicate that the ultrasonic vibration has considerable effect on reduction of temperature, depth of thermal damage of workpiece and width of temperature contours. Maximum temperature reduction of 25.91% was reported at condition of vs=15m/s, vw=500mm/min, ae=0.4mm in the presence of ultrasonic vibration.