Guan Xin Chi

Fabrication of Micro Parts with Micro-WEDM

A new Micro-WEDM machine is developed in this paper. Therefore, experiment can be done on this machine. Especially, the surface characteristics of work-pieces are analyzed in detail. The Micro-WEDM can machine micro slot easily. In addition, all kinds of micro shaped holes, micro gears, complex micro parts and dies are machined to check its processability. A micro gear can be easily fabricated by micro-forming method with the micro gear dies fabricated by micro-WEDM, and get well performance, which indicates that micro parts machined by Micro-WEDM meet the requirements of micro instrument and device.

Design of Scanning Micro-Arc Oxidation Forming Ceramic Coatings on 2024 Aluminium Alloy

Micro-arc oxidation (MAO), also called plasma electrolytic oxidation (PEO), anodic spark deposition (ASD), or micro-arc discharge oxidizing (MDO), is an effective surface treatment technique which come from anodic oxidation technology. Via increasing the anodic voltage breaking through faraday area to a high stage accompanied by micro-arc discharge phenomenon, It indicated the ceramic coatings thickness increase along with the scanning times increase, while the thickness increment reduces. The phase composition, morphology and element distribution was studied by X-ray diffraction, scanning electron microscopy and line scanning. The morphology of the ceramic coatings shows it divided into compact layer and loose layer. And it composes of α-Al2O3 and γ-Al2O3.

Forming Ceramic Coating on Al2024 by Scanning Micro-Arc Oxidation

Micro-arc oxidation (MAO) is a novel technique to deposit ceramic coatings on the surface of valve metals such as Al, Mg, Ti and their alloys. The oxide films prepared by this technique have a dense structure, high adhesion and excellent integrated mechanical properties. This technique is especially suitable for the surface treatment of machine parts that work at high speed and have a higher demand for resistance to wear and corrosion. There have been many studies in this field in the last few years. The development of micro-arc oxidation and its applications in industrial field was reviewed. Based on conventional micro-arc oxidation, an innovative scanning micro-arc oxidation technology with visible advantages was developed in this paper. Moreover, verification experiment on scanning micro-arc oxidation was carried out, and the experimental results suggested that scanning micro-arc oxidation could be conduced at a high efficiency but low cost way. At last, the effects of scanning times on film thickness were discussed.

Multi-Axis EDM CNC System Based on RT-Linux

In order to manufacture geometrically complex or hard material parts, a new kind of multi-axis electro-discharge machining (EDM) computer numerical control (CNC) system, which is based on RT-Linux platform, was presented. Dual-kernel structure of System is adopted: Linux and RT-Linux are used to realize Time-sharing tasks and Real-time tasks separately. The system is divided macroscopically into two parts: Real-time part and Time-sharing part, microcosmically into three modules: Real-time Control Module, Drive Module and CNC User Module. Through the communications among them, three modules construct the whole system. Rimed Turbine Blisk was experimentalized to validate the performance of the system. The process and the results implied that the system is Real-time, stable and reliable.

Study of combined process in micro-EDM

Micro-EDM is a flexible process which has many technique methods such as forming, drilling, milling, copying and WEDM. Combined these methods together can enhance the EDM machining ability. In this paper a set of route design regulations used in combined machining is proposed. Through these regulations, the optimal route of combined process can be obtained which can improve high machining quality and efficiency. To test performance of the regulations, the combined route of a micro part is designed and its fabrication is performed at last.

Influence of the Processing Parameters on the Coating Hardness on LD10 A-Alloy

The paper discusses the influence of processing parameters on the hardness of LD10 aluminum alloy coating treated by the power source with positive and negative pulse in the alkaline electrolyte. Lots of experiments were done with different processing parameters including positive current density, negative current density, frequency, duty ratio, processing time and electrolyte temperature, and the micro-hardness tester HVS-1000 was used to measure the coating hardness. The results indicate that elevating the duty ratio, or reducing the frequency can be advantageous to improve the coating hardness, and the coating is the hardest treated in electrolyte at the 30°C. And when the value of the positive and negative current density is reasonable, and the processing time rationally matches with the current density, the coating with HV2800 can be obtained.

Tangent Hole Machined by Micro Electrical Discharge Machining

Based on a self-developed pulse power supply, effects of working fluid to machining efficiency and relative wear of electrode are studied. tangent-hole machining experiments are designed and carried out. Tangent holes with 0.75mm and 0.56mm diameters on some nozzles are obtained.

Development and Experimental Study of Multi-Axis Micro-EDM Machine Tool for Small-Hole Based on Linear Motor

A multi-axis micro-EDM machine tool for small hole is developed. It mainly includes marble base, precision servo and linear-motor platforms, RC pulse power supply, CCD microscope and so on. Superiority of linear motor used on the Z axis is analyzed. Primary experiments, in which small electrodes with different materials are used to machine 3mm thickness TC4, are carried out. Histograms of open-circuit voltage and capacitance to machining efficiency and electrode relative wear and small-hole samples are given. Influence rules of open-circuit voltage and capacitance to machining efficiency and electrode relative wear are analyzed according to experimental results.

Design of Energy-Controllable Pulse Generator on Micro WEDM

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.

Model of Start-Stop Control on Low Speed Moving

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.