Enhancement of product quality and productivity of a small household electrical appliance company using microcellular injection molding technology

Abstract

The Small Electrical Household Appliance (SHEA) manufacturers in Hong Kong are encountering an unfavorable business environment because of the increase in material/labor/overhead costs in China. The profit mode of the industry is shifting from economy of scale to economy of scope, and the range and quality of products are of paramount importance for winning orders. The development of new products drives companies to pursuit innovative processing technology. The partner company of this project has invested in Microcellular Injection Molding (MuCell IM) technology; the ability of this technology to provide economy benefits to the automobile, office equipment and consumer electronic industries has been proven. However, the possibility of enhancing the productivity in relatively less sophisticated and value-added SHEA products is questionable, and a roadmap for MuCell IM technology implementation is not available. The change in material properties and the incomplete process logistics of MuCell IM technology lead to a lack of capability of the engineers/designers in the company to predict product performance and optimize the process parameters settings. Therefore, fundamental understanding of all the relevant steps along the process chain is mandatory in order to select the right candidate for the appropriate application and determine the right processing conditions for a reasonable justification. In order to cope with the above scenario, a structural approach for MuCell Injection Molding Implementation (MIMI) is developed. It is argued that the MuCell technology can be appropriately adopted with the deployment of the proposed system and the product quality and productivity can be enhanced with MuCell IM technology. The research methodology consists of six steps: (i) Identification of the Ungoverned MuCell IM Product and Process Design Parameters and Formation of an Axioms Library, (ii) Decomposition of the Product and Process Design Requirements for SHEA Products, (iii) Supplementation of Incomplete Axioms for the MuCell IM Process, (iv) Development of a Product Selection Scoring Checklist for MuCell IM Applications, (v) Development of a Systematic Approach for MuCell IM Process Design and (vi) Performance Evaluation and Justification. The proposed model has been verified through a case study involving toasters in the partner company. The projected annual cost saving is HKD 3.5 million provided that the components are correctly selected and the process parameters are properly designed. The majority of savings for thin wall components is due to scrap reduction (10%), with improved product conformance, whilst the major achievement in thick wall parts is attributed to scrap (4%) and material reduction (15%). During the implementation of MuCell IM to SHEA products, it was found that the compatibility problem of machine configuration with products and the extensive experimental resources are the two major considerations before investment. Alternatively, certain potential benefit is found in designing the product with the foaming process, which can further improve product quality, productivity and product scope of a SHEA company. Lastly, this work demonstrates how the productivity concept can be applied to manage MuCell IM technology in the SHEA industry and it is concluded that the deployment of MuCell IM to enhance SHEA industry productivity is profitable, but extensive effort has to be paid in experimentation, product validation and continuous development.