The Study Of Product Redesign Requirements Based On Customer Requirements And Failure Data

With the unceasing change of the market,the increasingly fierce competition between enterprises and the continuous increase of the consumer demand for products,manufacturing enterprises face the great challenge of product development and redesign improvements.Currently,product designers also take user experience and customer satisfaction as the goal of product redesign and the important index of measuring merits and demerits of design scheme.In addition,the failure data is accumulated during manufacturing,testing and operating of the product,which often implies design defects of the product.Therefore,the product that has the poor customer feedback and frequent failure need the improvement and redesign to enhance customer satisfaction and reliability.The premise of the redesign is obtaining the redesign requirements.The existing redesign method mainly considers customer requirements and satisfaction.Failure information of the product is mainly used in maintenance while less applied in product design and redesign.FMEA analysis identifies the weak links of products or systems from the point of failure and reliability,but it doesn’t comprehensively consider the effect of market and customer requirements,which may lead to the identification of the weak links insufficient or redundant.For the above problems,customer demand information and failure information of the product are both considered in this paper to guide product redesign.Customer requirements and failure risk of the product are analyzed respectively and the two-stage research of product redesign requirements is also presented.The first stage is to identify the weak product modules which need to be redesigned.These weak modules have low customer satisfaction level and poor reliability.The second stage is to provide the redesign targets of product modules,that is to say,allocating reliability for the weak product modules identified above.Then target reliability allocation scheme is provided so as to guide the redesign for weak modules.This paper mainly contains the following contents.(1)The methods of determining the customer requirements importance of product modules based on competitive analysis and determining the failure risk importance of product modules based on FMEA analysis are presented.Analyzing customer requirements for the product and improving the method of determining the importance of customer requirements with the comprehensive consideration of the current satisfaction situation data of customer feedback and the performance data of competitive enterprises,thus the correlation function from product modules to the overall customer satisfaction is established.Failure mode and effect analysis is carried out on the product.The failure risk importance of product modules is determined based on the fuzzy uncertainty failure data.(2)The multi-objective optimization model of product redesign modules identification is established.Take the customer requirements importance and the failure risk importance as the input,the two optimization objectives of maximizing customer satisfaction and product failure risk reduction level are obtained.Under the constraints of redesign cost and redesign cycle time,the multi-objective product redesign modules identification model is established to identify the weak modules which need redesign.(3)Reliability allocation solution for the weak product modules is provided.According to failure observation data and failure probability distribution,reliability modeling and target reliability optimization are carried out for weak product modules.The reliability allocation model of one weak module is established under the objective of minimizing the reliability cost to determine the reliability values of the weak module and its component parts.Finally,an auto-crane redesign requirements analysis case is implemented to expound the reasonableness and feasibility of the proposed framework which includes redesign modules identification and reliability allocation optimization.The case analysis of auto-crane has determined the weak modules of auto-crane and the reliability allocation target for their redesign.The present customer satisfaction situation and the failure information of auto-crane are researched and collected in this paper,and redesign requirements are also obtained for crane product.The redesign requirements provide the guidance of product redesign for the enterprise,which is of great significance for meeting the demand of customer,improving quality and reliability of the product,decreasing failure rate and reducing the damages caused by failure.