Papers by Author: Guo Hui Cao

Abstract: Generator is one of the key factors in Micro WEDM, which can affect machining quality, precision and efficiency largely. The factors influencing discharge energy are discussed and analyzed, the pulse addition method increasing energy density under maintaining the single pulse energy is advanced. To reduce the influence of voltage to single pulse energy, the gap voltage is also controlled. The generator is designed and the validating experiment shows this generator can increase machining efficiency and quality to a certain extent.

Abstract: This paper analyzes the cause of overshoot and retarded response in controlling piezoelectric ceramic motor with PMAC card in micro WEDM. The model of start-stop control is presented, and the servo control card with start-stop control is also developed. The model reserved the advantages of traditional PID control, and overcome the problems of overshoot and retarded response. It has been verified by machining that system overshoot is less than 3 pulses and response time is less than 1 second.

Abstract: A new micro EDM method is described. First, the basic principles of micro EDD are analyzed and realized conditions are predicted. Then with an ordinary EDM shaping machine and electrode brass, steel and tungsten, a large number of experiments are carried out in air to obtain the effects of different processing parameters on micro EDD. A micro cylinder with 0.19mm in diameter and 7.35mm in height is formed on high-speed steel surface. By exchanging the polarities of electrode and workpiece the deposited material can be removed selectively, thus the reversible machining is realized. In the end, measurements show that the deposited material is compact and hardened, whose components depend on the tool electrode material although Zn in brass electrode is oxidized to ZnO.

Abstract: This paper proposes a new deposition method using micro electrical discharge machining (EDM) to deposit micro spiral structure in gas. First, the basic principles of micro electrical discharge deposition (EDD) are analyzed and the realized conditions are predicted. Then with an ordinary EDM shaping machine, brass as the electrode, high-speed steel as the workpiece, a lot of experiments are carried out on the micro spiral structure deposition in air. The effects of major processing parameters, such as the discharge current, discharge duration, pulse interval, gravity and working medium, are obtained. As a result, a 19-circle micro spiral structure with 0.19mm in external diameter, 0.1mm in wire diameter and 3.39mm in height is deposited. Measurements show that the deposited material has obvious delaminating structure, the components of which depend on those of the tool electrode material, although Zn in the electrode is oxidized to ZnO. This method establishes the research basis for micro three-dimensional deposition machining.

Abstract: A new deposition method is described using EDM to deposit tool electrode material on workpiece in air. Then by exchanging the polarities the deposited material can be removed selectively, thus micro structure can be fabricated. First, the EDD realized conditions are predicted. Then with ordinary brass, steel and tungsten electrodes and high-speed steel workpiece, EDD experiments are carried out to obtain micro structure in air. With continuous deposition strategy of single cylinder, a HIT character type array made up of 15 micro cylinders is deposited. And micro three-dimensional spiral structure can be obtained with brass electrode using feed of only z axis. The 19-circle micro spiral structure is 0.19mm in external diameter, 0.1mm in wire diameter and 3.39mm in height. Measurements show that deposited material has obvious delaminating structure and is corrosion resistant, whose components depend on those of the tool electrode material.