This paper describes surface modification and surface deposition using a high-peak current discharge in an air gap and describes the relation between capacitance, which determines the peak current, and the deposition rate. The process is controlled manually using a rotating tool. The discharge circuit is a resistor-capacitor (RC) circuit, and switching is executed by means of a thyristor. The deposition of nickel onto a steel surface was performed using a nickel-based alloy for the electrode. The electrode was controlled with reciprocating rotation. The influence of the capacitance of the capacitor and the diameter of the electrode on the deposition rate was investigated. Using the proposed method, excellent surface deposition was achieved.
Recently, many surfacing processes, such as coating have been widely applied to the industrial products in order to improve the surface functions. One of the practical surfacing processes is a sputter deposition, in which the sputtered target material is deposited on the substrate surface. This method can be used not only for metals but also for insulators and plastics materials as substrate surface. In this study, the possibility of sputter deposition by using a large-area electron beam was discussed. If the target material deposits on the substrate surface simultaneously with the surface melting and resolidification of substrate material by large-area EB, the adhesion between the deposited film and the substrate surface would be strong. Alloy tool steel SKD11 was used as a substrate material, and pure metal tube made of nickel or titanium were used as a target material. Then, the substrate surface after EB irradiation was analyzed and the surface characteristics were investigated.
A multi-layered artificial skin is mainly consisted of three layers of silicone elastomer, print paper, and resin plate. Sealing of facial defects with the multi-layered artificial skin causes perspired water from the surface of missing parts, which results in insanitary conditions to the skin surface. Therefore, the laser micro-drilling using nanosecond pulsed laser of 266 nm was investigated to provide the breathability for multi-layered artificial skin without human eye’s recognition of drilled holes, which can satisfy both the breathability and aesthetic problems. The visibility of drilled hole was affected by the pitch distance of drilled holes, and its visibility decreased with increasing the pitch distance. A small color difference measured using a colorimeter led to the low visibility, and laser micro-drilling with small color difference is effective to obtain the breathable multi-layered artificial skin with low visibility of drilled holes, which can improve the breathability for the multi-layered artificial skin.
It is known that good surface roughness can be achieved by ECM with a high current density. However, when the tool electrode moves across the surface of the workpiece the low current density area which follows the high current density area roughens the surface. Attempts to suppress the effect of the low current density area by utilizing pulse currents to obtain a glossy surface were made. This paper reports the experimental results of ECM with a moving wire electrode on an EDMed surface to investigate the effect of various conditions on the machined surface.
The performance of an in situ internal stress measurement technique using a Shack-Hartmann sensor (SHS) is examined during nickel electrodeposition in concentrated nickel sulfamate solution. The stress is calculated from the change in the curvature of a test plate bent by stress. The curvature is measured by monitoring the wavefront of an expanded laser beam reflected at the substrate using an SHS. Applying the proposed method, curvature measurements were conducted and the repeatability and accuracy were estimated. In situ stress measurement with a current density of 2.1 mA/cm2 revealed a repeatability of approximately 1 MPa when the thickness of the nickel layer was 19 μm.
In this study, WC alloy micro-pins were fabricated by electrochemical machining using a NaNO3 aqueous solution and bipolar pulse supply. Since the influence of the pulse conditions on micro-pin formation is still unknown, the micro-pin fabrication was carried out by changing the pulse period, the pulse width, and the power supply system. Since finding what happens in the inter-electrode area may be helpful to understand the mechanism of machining using bipolar pulses, observations of the micro-pin surface during the process were carried out using a high-speed camera. As a result, it was found that the colour of pin surface becomes blue momentarily when the pulse voltage falls in the case of using a bipolar pulse power supply. In addition, the relationship between the pulse waveform and the blue appearance period was experimentally investigated anddiscussed.