The New Method And Equipment Of Automatic Judgement For Bentonite Content Based On Image Recognition Technology

Clay-bonded sand casting process is one of main methods for foundry industry. Clay-bonded sand is composed of clay, raw sand, bentonite and coal powder. Determination of effective bentonite content in moulding sand or used sand is essential for the sand casting performance testing. Currently, domestic enterprises mostly adopt SEL, a traditional type of detector, operated in a manual way with measurement methods. However, the testing cycle is long, efficiency is low, and also,the accuracy is not high. This paper is focused on the automation of the detection method and apparatus.Firstly, this paper introduced the traditional principles of effective bentonite content detection method. Based on the analysis and summerize between domestic and international research, adopted the traditional determination of methylene blue adsorbed as the core, as well as the introduction of digital image processing, an automatic determination based on image recognition method is proposed. Secondly, summerize statistical data to determine the value of measuring the end point accurately. In this design, the bare human eye was substituted by image system to complete recognition processing, the communication with host PC was finished by embedded microprocessors, and then a set of automatic analyzer, with all functions of transfering droplets, image acquisition, image identification, analysis, was developed.As for the part of hardware system, the design was detailly described, including the mechanical hardware solutions, the selection of the hardware modules and the ARM processor chip in control board and the design of peripheral expansion circuit. Hardware control panel adopted STM32 chip as the core chip. Data was transferred from the MV-200UC image acquisition to PC through USB port in the board. The communication between entire embedded development board and PC was achieved through UART serial.As for the part of software systems, in-depth study of the image analysis algorithm has been built on the basis of the exsisting image processing platform. Furthermore, the underlying drivers associated with embedded operating system were developed with the help of Keil C software platform. Finally, using C language, the system PC software was completed in accordance with software design specification. Through this study, new automated measurement methods and instruments for the foundry industry in the area of sand performance testing were promoted. With further improvement, the system can be a better role in resolving efficiency and accuracy issues which existed in traditional manual measurement. Thus, it has made insurance in controlling moulding sand stably and producing high-quality castings, as well as promoting the foundry industry to achieve a new era of "Green Casting" gradually.