Rapid Application Development of Process Capability – Supplier Models

Rapid changes and specialization in technology make it increasingly difficult for designers to keep track of the current capabilities of manufacturing processes and choose the appropriate one. Improper process selection leads to higher costs, lower quality and wrong choice of supplier. Currently, there is no software advisory system to help the design/procurement personnel in process and supplier selection. The complexity involved in building an application encompassing the capabilities of dozens of processes and its associated suppliers acts as a deterrent for application service providers. This paper discusses a technique to rapidly develop web applications to identify a suitable manufacturing process and supplier/s using Rapid Application Development (RAD). RAD refers to a new computing paradigm to develop software applications within a short time frame. The technique has been verified by developing an advisory system to identify a suitable plastic process and supplier/s. The methodology is currently limited to common manufacturing methods such as castings, forgings, sheet metal and plastic/composite manufacturing. Benefits realized using RAD include shorter design and development times, code reusability and standardization. NOMENCLATURE RAD: Rapid Application Development PPA: Plastic Process Advisor MPA: Metalcasting Process Advisor MPSA: Manufacturing Process and Supplier Advisory system ASP: Application Service Provider INTRODUCTION Decisions made during the design stage have a significant impact on the final cost and quality of the product. Studies have indicated that although the cost of product design is only around 5% of the total product cost, decisions made during the design stage affect 70-80 % of the final product cost [13]. Some of the important decisions made concern manufacturing process selection. It is essential for the designer to select a process whose capabilities best match with the design. A survey of designer’s knowledge of processes [3] indicated that more than 90% knew little or nothing about plastic processes such as injection molding and extrusion. The figures were equally high for other processes such as sintering and cold heading. This indicates the need for a software tool to help designers become aware of the factors governing process selection and the capabilities of the various processes. The factors that influence process selection [7] are cost of manufacture/life cycle cost, quantity required, complexity, material, quality and availability/lead time/ delivery schedule. All these are called user requirements. For example, the user requirements for a part that needs to be cast can be expressed in terms of casting complexity, pattern and die cost, order quantity, surface finish, tolerances, cost of machining, strength, weight and choice of material [12]. These requirements should be matched with the capabilities of various casting processes and a proper casting process selected. Processes belonging to other manufacturing methods such as forgings and sheet metal may also need to be investigated. Once the process is decided, the next stage is to select a supplier capable of using the process. Criteria for supplier selection include technical capability of the supplier, supplier production facilities and capacity, suppliers’ geographical location etc. [6]. Some or all of these form the user requirement for supplier selection. MPSA (Manufacturing process and supplier advisory system) is a web based process/supplier advisory system that we have developed. MPSA evaluates these user requirements and suggests an appropriate process and supplier/s to manufacture a part taking into consideration the process and supplier capabilities. It currently consists of Metalcasting Process Advisor (MPA) and Plastic Process Advisor (PPA). The latter was developed using the RAD model discussed in this paper. Previous Research Advisory systems developed earlier include the Manufacturing Advisory System (MAS) used for process and material selection [8]. MAS clubs processes (sand casting, closed die forging etc.) from different manufacturing methods (castings, forging, sheet metal etc.) together for consideration. For Example: Metalcasting processes such as sand casting and die casting are combined with forging processes like closed die forging. The input attributes for process selection such as geometry, material, desired tolerance, finish etc. are the same irrespective of the specific manufacturing method. Other process and material selection applications include the system proposed by Boothroyd et.al [4] where the inputs to the system