Technological Study To Controlling Process Of Microarc Oxidation On Forged Aluminum

Aluminum has been broadly used in the engineering field due to its broad reserves, low density, great intensity and excellent performance in extrusion process among all the metal materials. However, the crucial disadvantages of aluminum are its softness, easy to wear and easy to be corroded in the medium, which lead to the failure of the products. The oxidized coating in the traditional coating technology, i.e. anticathode-oxidation, chemistry-oxidation, is to a large extent relatively thin, lower in hardness, and some process technology even cause a severe pollution to the environment, which is no longer feasible to the practical application.Microarc-oxidization is a deposition technology of plasma electrolysis, a coating technology which produces the ceramic coating in the surface of non-ferrous metals such as aluminum, magnesium, titanium and its respectively alloy materials via the joint reaction of high pressure electricity discharge and electrochemistry oxidation in an electrolyte contained certain ion. It breaks through the voltage limit of traditional anticathode-oxidation and obtains the idea ceramic coating in the surface of the said metals via the strengthening reaction of high pressure electricity discharge. Micro arc-oxidization technology is a technology of simple product process, non-pollution and high capacity of processing workpiece, which greatly improved the performance of aluminum and its alloy and lead to the perfect combination of the second-generation engineering materials (metal) and the third-generation engineering materials (ceramic), which is a very promising lightalloy coating technology.Due to the difficulties in the research of the technics mechanism of microarc-oxidization, the development of the research of industrialization application of micro arc-oxidization techniques and the high-power electrical source that goes with a large scale industrialization and automatic production line is slow.This paper, on the basis of microarc-oxidization power supply which was developed by our laboratory, carries out the automatic control of forged aluminum microarc-oxidization technics via controlled circuit and adjustment of software by using of PIC16F788A single-chip as the core controlling chip in order to change the nature of the surface of forged aluminum and enhance the production efficiency of microarc-oxidization technics. This paper, based on the particular demands of coating processing of plasma microarc-oxidization techniques,in consideration of all kinds of factors, designs a controlling system of plasma microarc-oxidization techniques. This system is an on-site controlling unit consists of single-chip and its relevant peripheral equipments to carry out the automatic controlling of microarc-oxidization. Its main research includes: the design of on-site controlling system of plasma microarc-oxidization and modules of main controlling program; the design of circuit of data input and output, modules of key controlling software and modules of D/A conversion software; the design of display circuit and liquid crystal display circuit.By using the controlling system of microarc-oxidization techniques developed by our laboratory, inputting the certain technics parametric, combining the main circuit, letting the controlling system monitor the whole microarc-oxidization techniques process, the experiment shows that the controlling system of plasma microarc- oxidization is reliable. All the technics parametric of microarc-oxidization can reach its goal. Meanwhile, the actual operation on the spot also shows that the controlling system improved the accuracy of repeated control of microarc-oxidization techniques, reduced the intensity of labors and cut down the production cost.