Papers by Keyword: Female Screw

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Authors: Pai Shan Pa
Abstract: This study discusses electrochemical finishing of female screw using different types of completely inserted electrodes as well as feeding electrodes for die material. In the experiment, four types of design electrode are completely inserted and put through both continuous and pulse direct current and another four types of electrode are used with the application of continuous direct current and axial electrode feed. The controlled factors include the chemical composition and the concentration of the electrolyte, the electrolyte temperature, the flow rate of electrolyte, rotational speed of the electrode, current density, and current rating. The parameters are electrolytic time, die material, pulse period, feed rate of the electrode, and electrode geometry. For inserted electrodes, an electrode with thin plate provides more sufficient discharge space, which is advantageous for polishing. The electrode of single plate performs better than the double plate. Pulse direct current can promote the effect of electrochemical finishing, but the machining time is longer and the cost is raised. For feeding electrodes, an electrode of one side borer tip and thinner heavy section performs the best polishing effect in the current investigation. The electrochemical finishing after screw cutting just needs quite short time to make the surface of female screw smoothing and bright.
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Authors: Pai Shan Pa
Abstract: It is very difficult to execute the finishing process of the concavo-convex surface of female-screws. The current study offers a screw-form design electrode and a new area-finishing process using an ultrasonic generator. The ultrasonic energy generated is transmitted into the electrolyte to assist the process of electrochemical finishing. The surface of female-screws is electrochemically finished by different types of completely inserted electrodes and put through both continuous and pulsed direct current as a finishing operation. For inserted screw-form electrodes, a smaller circumference electrode on the cylinder provides more sufficient discharge space, which is advantageous for finishing. Pulsed direct current can promote the effect of electrochemical finishing, but the machining time is longer and the cost is raised. The average ultrasonic effect is much better than the pulsed current while the machining time needs not be prolonged by the off-time. The higher current density and higher current rating with ultrasonic assistance can avoid the difficulty of dreg discharge, thus reducing the finishing time. It is a great contribution that the ultrasonic-assistance electrochemical finishing after screw machining requires a shorter time than manual or machine polishing to make the surface of female screws smooth and bright.
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