Determination of Cutting Transition Parameters in the APQP Pre-production Process of the Engine Camshaft Bearing Housing

Abstract

An example of the application of the experimental planning method in the APQP pre-production process to find the values of the cutting process parameters that provide a given margin of accuracy is considered on the example of roughing and finishing boring of the inner hole of the camshaft bearing housing. From the total set of geometric parameters, special characteristics are highlighted - the size of the inner hole, which ensures the fit tolerance of the steel-fiber sleeve and the height parameter of roughness Ra, as well as radial runout. The objectives and results of the application of engineering methods (calculation of allowances, dimensional analysis, evaluation of technological accuracy of machine systems, planning experiments) as well as special methods of APQP process (quality management tools - FMEA analysis, SPS, MSA) are considered. Attention is drawn to the insufficient information content of the methods, which does not allow for the selection of process indicators to ensure the necessary margin of accuracy of special characteristics. In order to achieve a given margin of accuracy, technological components of the internal diametrical size are identified - the deviation of the tuning size, the deviation of the cross-section profile and the height roughness parameter Ra, the values of which are found as a result of production experiments. The planning of a full-factor experiment is carried out according to the parameters of the cutting process - cutting speed, feed and cutting depth. To implement the plan, special samples of products with a stepped allowance were designed and manufactured. The shape of the product samples makes it possible to reduce the number of samples for a full-factor experiment from eight to four, providing a check of the linearity of regression models. The calculation and regression models are given, which allow predicting the values of the components of the internal diametrical size at the design stage of the manufacturing operations of parts. The solution of the regression model system that satisfies the specified limitations for a given margin of accuracy allows you to find the optimal range of values of the parameters of the cutting process, to provide rare settings of special characteristics in the serial manufacturing process of camshaft bearing housings. Systematic application of the methodology, along with statistical methods of quality management, allows monitoring the technical condition of equipment and maintaining it in the condition required for the production of quality products. Systematic application of the methodology, along with statistical methods of quality management, allows monitoring the technical condition of equipment and maintaining it in the condition required for the production of quality products.