Research Of Quality Cost Based On PONC Of Heavy Duty Machine Tools Manufacturing Process

The development of manufacturing technology makes the gradual increase of product quality among different corporations, but in the actual manufacturing process, reject, rework and other non-value-added activities brings the enterprise huge losses. Thus reducing the manufacturing cost of quality has become an important tool for enterprise to win the market competition. In the thesis, reject and rework cost generated during manufacturing was the research object, price of nonconformance (PONC, price of nonconformance) existing in the heavy-duty machine tool manufacturing process was studied, and the main research works were as follows:(1) Analyzing the necessity to research the PONC of heavy duty machine tools manufacturing process in allusion to problem that the price of nonconformance in heavy duty machine tools manufacturing process brings a large number of loss to the enterprise, the status quo of quality cost control of manufacturing process in domestic and overseas was summarized and the existing problem of quality cost control of manufacturing process was analyzed, the mostly research content of discourse was ascertained.(2) Using the production process of workshop as a research unit, PONC control principle based on the thought of PDCA was proposed, the mathematical model and allocation process of workshop objective PONC were established, workshop objective PONC was assigned to parts and working procedure based on Activity-Based Costing, working procedure objective PONC was formed. Quality loss cost in manufacturing process was calculated using system engineering theory, the working procedure PONC control system was built. The influence factors of working procedure PONC were analyzed using Analytic Hierarchy Process, the function between working procedure PONC and influence factors was established, all of this lay the foundation for achieving quality cost control.(3) Using the shaft sleeve processing workshop and transmission shaft of heavy duty machine tools manufacturing enterprise as an object to research the working procedure PONC. The objective PONC of shaft sleeve processing workshop was analyzed, the function between workshop objective PONC and mass loss rate was established, the working procedure objective PONC allocation model of transmission shaft was proposed, the activity center and cost driver of transmission shaft manufacturing process were determined, the specific allocation path of working procedure objective PONC was built. The cost items of reject, rework and retest PONC in heavy duty machine tools manufacturing process were analyzed, the function of quality cost in manufacturing process was established, the influence factors of manufacturing process PONC were analyzed, the importance of influence factors were determined.(4) The structure of PONC control and information management system of heavy duty machine tools manufacturing process was established, the main module function and the operating procedures were analyzed, the PONC control and information management system was devised. According to the mathematical model of working procedure PONC in actual manufacturing process, PONC control and information management system of heavy duty machine tools manufacturing process was developed using Microsoft Visual C# computer language to achieve the function of acquisition, operations, add and store of reject and rework PONC related data, and to achieve the prevention and control of PONC in manufacturing process and working procedure PONC diagnosis.(5) Take the manufacturing process of typical part of heavy duty machine tools—large transmission shaft for example to analyze working procedure PONC. The objective PONC of shaft sleeve processing workshop and the objective PONC of large transmission shaft were calculated, the objective PONC of large transmission shaft was assigned to activity centerbased on Activity-Based Costing, working procedure objective PONC was determined. The working procedure PONC and working procedure objective PONC of actual manufacturing process of large transmission shaft was compared, the reason of working procedure PONC beyond the standard was analyzed, the improvement measures were proposed, and the effectiveness of system was verified.