Study On Engineering Change Impact Evaluation For Manufacturing Enterprise

Engineering changes are inevitable to a modern manufacturing enterprise. They widely exist in nearly all departments of the enterprise during the entire product life cycle. Engineering change management is a very important activity in the daily production and operation of the enterprise. Engineering changes can bring some benefits to enterprises but may cause some loss at the same time. Therefore, it is a very important aspect of engineering change management to correctly measure the pros and cons of a change and make the right change decision. Based on a comprehensive analysis of the existing engineering change management theories, the paper established a complete theoretical system of engineering change impact evaluation, which can quantitatively evaluate the potential benefits, losses and risks caused by a certain change. A comprehensive evaluation result can be obtained as a decision-making reference.Firstly, after a thorough research on the basic theories of the engineering change impact evaluation and a summarizing of the existing evaluation methods and principles, the paper selected the key technologies of change evaluation by using the theories and methods from economic management, system engineering, risk management and other fields. The Analytic Hierarchy Process (AHP) method is introduced into change impact evaluation. It can make the decision-making process of complex systems hierarchical, combine the qualitative and quantitative factors in the evaluation process and express the subjective judgment of people in a scientific quantified form. Through this way, the contradictory between weight prediction and the actual situation caused by people’s inaccurate subjective judgment can be avoided and thereby improving the effectiveness and accuracy of the engineering change decision-making.Secondly, the paper analyzes the engineering change evaluation factors and proposed the construction method of evaluation index system based on the three evaluation factors, cost, benefit and risk. A set of evaluation methods and theories for these three evaluation factors are created. As to the cost factor evaluation, the composition of costs during the change implementation process is analyzed and several detailed calculation formulas are proposed. Under the guidance of similarity costing method, the cost of the product after change can be estimated using the Exponential Smoothing method and the Analytic Hierarchy Process method. The detailed calculation formula of overall cost is introduced. As to the benefit and risk factors, the Analytic Hierarchy Process method and Experts Grading method are introduced to calculate the weights and values of evaluation indexes respectively. Based on the above study, the calculation formula of converting the evaluation vales of benefit and risk factors into monetary equivalents is proposed. Through this formula, the evaluation results of the three factors can be integrated into a final comprehensive evaluation value, which can be used as a key reference of engineering change decision-making.On the basis of the above theoretical studies, a computer-aided engineering change evaluation system is designed, which can help evaluators complete the evaluation work accurately and efficiently. The development environment and functional requirements of the system are analyzed; the workflow and functional modules of the system are introduced in detail; the system interfaces are designed and the function of some key calculation modules is realized.