An Internet-based Application System For Surface-Texture Software Measurement Standards

For surface texture measuring instruments, the reliability and accuracy of the embedded analysing and evaluating software are as important as those of their hardware, which will significantly affect the integral performance of the instruments. Most of surface texture measurement instruments are claimed to be manufactured according to ISO 4287(1997), however, the undetailed defined parameters, and ambiguity existing in some of the parameters will lead to different interpretations thus to different algorithms in calculating the surface texture parameters. In order to verify the accuracy and the precision of the embedded evaluating software of instruments, ISO 5436-2 (2001) introduced the concept of software measurement standard. In this paper, the internet-based application system is developed according to ISO 5436-2 (2001).The research background, theory foundation of software measurement standard were firstly introduced. By inputting the same profile data into the application systems developed by National Physical laboratory(NPL) and National Institute of Standards and Technology(NIST), also into three surface texture evaluation softwares from other companies. From the different results got from the same data, the ambiguity and incompletion of the parameters definition in standard were investigated. Secondly, three different types of the data format, namely ASCII, SDF(Surface Data Format) and SMD(Softgauge File Format) were analysed, based on which, a file format converter was programmed. The mechanism and method for developing the reference data set were discussed. Thirdly, some of the parameters in the standard are defined in the continuous form while in practice, the sampled profile data is in discrete form. This will cause noticeable errors. So the natural cubic spline was used to interpolate the data before the surface texture parameters calculation. A specification was finished for Gaussian filtration, which will make the error small to some extent. At last, the Internet-based Application System for Surface-Texture Software Measurement Standards was finished based on the VS.NET platform. The powerful scientific computing programme Matlab was used to develop the algorithms, which were then encapsulated in the DLL (Dynamic Link Library) files by VC++. The DLL files were then transferred by the web program which ensured the quick response of the web-based system.