Computer-Integrated Ceramics Manufacturing Dan Bin, Liu Fei and Cao Le Institute of Manufacturing Engineering Chongqing University, Chongqing, China

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1 Computer-Integrated Ceramics Manufacturing Dan Bin, Liu Fei and Cao Le Institute of Manufacturing Engineering Chongqing University, Chongqing, China Computer-integrated manufacturing technology can enhance design, manufacture and management systems while decreasing inventory and lead time for delivery and increasing customer satisfaction. CAD/CAM (computer-aided design/computer-aided manufacturing) is the most common modern design and manufacturing technology used in ceramics manufacturing. It is used in realistic modeling design, decorative pattern design, relief design and automated machining of ceramic products. Orozco, for example, developed a computer system for the automated product design and manufacture of dies for advanced 3-D forms in the porcelain industry. 1 Delcam put forward the Power Solution, a series of CAD/CAM software suitable for ceramics. 2 Wedgwood introduced major efficiency into its operations by combining traditional craftsmanship with computer-supported design and modeling. 3 Royal Doulton applied CAD to design its new Oceana range taking half the time that it would have taken using conventional methods. 4 Griffiths has discussed computer-aided pattern design and ceramic transfer printing, which has changed as a result of the introduction of CAD. 5 Helgesen applied CAD/CAM to transpose design data into instructions that were fed into a multi-axis milling machine. 6 In addition, the rapid prototype technology and management of material and information flow also were applied in ceramics. 7, 8 The aforementioned technology, however, is mainly local automated technology or local integrated technology. The global integration of overall product design, production and management of a ceramics enterprise, e.g., computer-integrated manufacturing (CIM) in ceramics, has not been extensively researched or applied. CIM for Ceramics Traditional manufacturing processes for ceramic products usually are serial and time consuming. From order to final product, American Ceramic Society Bulletin, Vol. 80, No. 3 27

2 Computer-Integrated Ceramics Manufacturing there are 10 serial steps. These include modeling design, process planning, mold design, mold trial production, whiteware trial production, evaluation by experts and customers, decorative porcelain trial production, evaluation by customers, mold production and porcelain production. Ordering Decorative Pattern Design Decal Trial-Production Forecasting Modeling Design Process Planning Mold Design Mold Trial-Production Whiteware Trial-Prodcution Evaluation of Experts & Customers Pass Decorative Porcelain Trial-Production Fail Evaluation of Customers Pass Mold Production Decorative Porcelain Production Traditional manufacturing processes for ceramic products. Fail If porcelain samples fail to pass the evaluation, the manufacturer must return to the preceding steps, and a large investment of time and resources is wasted. To streamline the manufacturing process, a kind of CIM system has been built. It includes systems for engineering design, management information, reverse engineering, mold manufacture, decal manufacture, product (decorative porcelain) manufacture, database and computer network. The engineering design system contains five subsystems. These are the modeling CAD, decorative pattern CAD, decorative porcelain CAD, mold CAD and CAPP (computer-aided process planning) subsystems. The management information system also contains many subsystems, e.g., marketing management, finance management, production management, purchasing management, inventory management, etc. The database system is composed of databases for modeling, mold, decorative pattern, process, electronic warehouse of virtual products and management information. These are the essential databases for design, manufacture and management in a ceramics enterprise. When customers order decorative Reverse Engineering Engineering Design Modeling CAD Decorative Pattern CAD Decorative Porcelain CAD Mold CAD CAPP Virtual Products Experts and Customer Evaluation Mold Manufacturing Product Manufacturing Decal Manufacturing Management Information Marketing Management Finance Management Production Management Purchase Management Inventory Management Product Design Modeling Mold Decorative Pattern Process Electronic Warehouse of Virtual Products Management Information Computer Network Computer-integrated manufacturing system for ceramic products March 2001

3 Marketing Management Account Receivable Finance Management Account Payable Product Inventory Production Orders Inventory Management Whiteware Inventory Material Inventory Production Management Material Requirement Purchase Management Bill of Lading Payment Product Stores Whiteware Stores Material Stores Delivery Decorative Porcelain Whiteware Material Orders Customers Workshops Suppliers Order Payment Production Schedule Information Flow Material Flow Money Flow Integration of the management information system in a ceramics enterprise. porcelain, the manufacturer must first apply the engineering design system to design 3-D models of whiteware and decorative patterns and create virtual products, i.e., 3- D figures and motion pictures of the decorative porcelain on computers. Customers and experts can then evaluate the virtual products through a computer network. If the virtual products are not satisfactory, they may be rapidly and easily modified. If the virtual products satisfy them, the manufacturer will design the molds and plan production processes with the engineering design system. Manufacturers can quickly and subsequently produce the molds, the decals and the products. Finally, the management information system obtains the product information and realizes the integration of marketing, purchasing, inventory, production and finance information relative to the products. Key Technologies Information integration and process integration of marketing, purchasing, inventory, production and finance are the chief tasks of the management information system. After gathering information concerning marketing contracts and inventory, the marketing management subsystem generates production orders for the production management subsystem, the bill of lading for the product stores and the account receivables for the finance management subsystem. When receiving production orders and checking whiteware inventory, the production management subsystem generates the production schedule for the workshops and the material requirement for the purchasing management subsystem. The purchasing management subsystem then produces the material orders for suppliers and the accounts payable for the finance management subsystem according to the requirements and existing inventory. Finally, the finance management subsystem receives payment for products and pays for materials. The integration is supported by a Microsoft SQL Server database. Incorporating characteristics of ceramic design along with integrated technology is the aim of the computer-aided design system. Integration between the modeling CAD and the decorative pattern CAD has been realized, making possible the 3-D design of decorative porcelain. The integration of the modeling CAD and the mold CAD also has been achieved. Consequently, the integrative design of ceramic products and molds can be implemented. The subsystem of ceramic product data management has been developed for the integration between the engineering design and management information systems. The ceramic CAPP subsystem turns the nonstandard and experiential processes of traditional ceramics production into standardization and digitalization. Integrating Modeling, Decorative Pattern Delcam s PowerSHAPE has been used in the modeling CAD, and Corel s Coreldraw and Adobe s Photoshop have been applied in American Ceramic Society Bulletin, Vol. 80, No. 3 29

4 Computer-Integrated Ceramics Manufacturing the decorative pattern CAD. Autodesk s 3-DMAX has been used to affix the decorative patterns on the surface of the 3-D modeling and to create the 3-D decorative figures of the porcelain. The 3-D modeling of whiteware have been designed and converted into STL format files with PowerSHAPE. The decorative patterns have been designed with Coreldraw or Photoshop and saved as the pattern files, e.g., CDR, PSD, BMP, JPG or TIF format files. By inputting the STL and pattern files to 3-DMAX, sticking the decorative patterns onto the 3-D whiteware modeling and lighting up the decorative modeling, the decorative porcelain CAD subsystem can obtain 3-D decorative figures. If the 3-D decorative figures satisfy the experts and customers, the 3-D modeling data will be used for the mold CAD. The data of the decorative patterns will be used for printmaking and silkscreen printing of decals. Each ceramic product needs a set of molds, so there is great demand for mold design. The mold CAD subsystem has been developed to make mold design easy. The modeling CAD subsystem extracts whiteware profile information from the 3-D model and turns it into DXF format files. It reads the DXF files, generates the draft of the molds according to the whiteware profile figure and modifies them. Then, the mold CAD subsystem gets the mold figures. A subsystem of ceramic product data management has been developed for the integration of the engineering design system and management information system. When ceramic products are designed, the subsystem generates the BOM (bill of material) of the products according to their design information and automatically lays the BOM into the database of the management information system. By this means, the engineering design system and the management information system are integrated. Virtual Ceramic Products The engineering design system has been applied to design the 3- D decorative figures of porcelain. Some problems distortion of the decorative patterns affixed on the complex curved surfaces, difficulty of locating the decorative patterns on the surfaces and transparency of the 3-D decorative figures have been solved successfully. Motion pictures of 3-D decorative figures are produced. Motion pictures of the porcelain on computers are called virtual ceramic products. The virtual ceramic products make it possible for customers to see the final show of products and give their suggestions to designers before production. Virtual ceramic products can be laid in electronic warehouses or electronic shop windows, where the customers can view them via the Internet. This is the basis of electronic commerce in the ceramics industries. Reverse Engineering Because of the complex curve surfaces and patterns, remodeling and retrofit play important roles in the design of ceramic products. Reverse engineering of ceramic products includes two parts: the reverse engineering of the 3-D modeling and the reverse engineering of the decorative patterns. There are three steps to the reverse engineering of the 3-D modeling. These are digitalization of curve surfaces, reconstruction of the curve surfaces and 3-D remodeling of the ceramic products. Since ceramic products accept large tolerances, the essential dimension precision of the reverse engineering is usually lower than that of general mechanical products. Quick and economical digitalization equipment, e.g., coordinate measuring machines and touch-pad 3-D scanners, can meet the demands of the reverse engineering of the ceramic products. In order to be measured rapidly and exactly, the characteristic points, lines and surfaces should be chosen carefully before being scanned or measured. Delcam's CopyCAD and PowerSHAPE are used to restructure the surfaces. CopyCAD is used to rebuild the surfaces from the measure data of the characteristic points. The rebuilt surfaces, which consist of many pieces of tiny triangle planes, are revised, combined and smoothed with PowerSHAPE. The 3-D figures of the products are then remodeled. For some products, their restructured surfaces may be redesigned aesthetically. There are two steps to the reverse engineering of the decorative patterns. These are the pick-up and the revision of the patterns. Two methods may be used to pick up the data of the patterns. If the original patterns are on plain paper or are photographs, they can be scanned with plain scanners. If the patterns originate from substances, e.g., flowers, fruit, etc., they can be obtained with digital cameras. Original patterns are then revised and redesigned with Photoshop to become the decorative patterns needed. Reverse engineering makes the design of the decorative patterns more efficient. Case Study CIM technology and systems have been applied by Chongqing CHN & CHN Ceramics Co. Ltd., a ceramics producer in China whose products have been selected as the tableware 30 March 2001

These systems are integrated and can transmit design and production data to workshops and decal factories.

5 for the national feast and for Virtual products of the Millennium range. (l) coffee pot, (r) sugar bowl. national gifts. The computer network, database, management information, engineering design and reverse engineering systems have been developed and implemented. These systems are integrated and can transmit design and production data to workshops and decal factories. The computer network and database systems support operation of the management information, engineering design and reverse engineering systems. The management information system has been applied in the marketing, finance, production, purchasing and inventory departments, making them automated and efficient. Communication and information transmission among the departments is convenient and rapid throughout the system. Dynamic data of inventories of products (decorative porcelain), the semi-products (whiteware) and the materials can be obtained simultaneously. Consequently, the marketing department can order precise quantities from the production department. The production department can then calculate an exact production schedule and the demand for materials automatically. It can send these to the workshops and the purchasing department separately. The purchasing department can calculate and order precise quantities of material. The finance department also can be apprised of this data and can calculate the financial data promptly. As a result of the application of this management information system, the inventory has been reduced from $4.26 to $3.67 million, and the average lead time for delivery has been shortened from 20 to 10 days. The engineering design system and the reverse engineering system have been applied in the product development department, the mold workshop and some cooperative organizations. The designers design the whiteware, decorative patterns, decorative porcelain and molds concurrently, and then upload the virtual products on computers. Virtual products are sent to customers via the Internet. If customers approve, the production process is planned. The whiteware data and molds will be used in manufacturing, and the decorative patterns data will be transmitted to the decal factories for printmaking and silkscreen printing. If customers request changes, designers can conveniently make modifications. For example, in September 1999, the company launched the new Millennium range. All products were designed and modified on computers. The cycle of product design has been decreased to half of the days it would have taken using conventional methods. Conclusion Research on CIM technology and systems in ceramics enterprises is both a technical and practical issue. It is significant to be able to enhance design, manufacture and management systems while decreasing inventory and lead time for delivery and increasing customer satisfaction. A CIM system for ceramic products has been built. It consists of the engineering design, management information, reverse engineering, mold manufacturing, decal manufacturing, product manufacturing, database and computer network system systems. The integrated technology of the management information system can transmit and integrate the dynamic information of marketing, inventory, production, purchasing and finance in a timely manner. This aids in the efficient operation and management of a ceramics enterprise. The integrated CAD technology makes it possible to design the whiteware, decorative patterns, decorative porcelain and molds concurrently. The technology of virtual ceramic products shows customers the final products before production and lays the foundation for electronic commerce of ceramics. Reverse engineering also plays an important role in design of the complex curve surfaces and the decorative patterns of ceramic products. Finally, the CIM technology and systems have been successfully applied in a ceramics enterprise. Acknowledgments This work was funded by The National High Technology R&D Project of China. References 1 J. Orozco, Product Design and Die Manufacturing in the Porcelain Industry Using Computer Integrated Techniques, Interceram, 47 [4] (1998). American Ceramic Society Bulletin, Vol. 80, No. 3 31

6 Computer-Integrated Ceramics Manufacturing 2 Delcam plc, Delcam s Power Solution, P. Dickin, CAD/CAM at Wedgwood, Am. Ceram. Soc. Bull., 72 [12] (1993). 4 Delcam plc, Fast Track Ceramic Modeling Creating a New Radical Design for Royal Doulton, 1.htm, B. L. Griffiths, Computer-Aided Design and Surface Pattern Decoration in Whiteware Ceramics, Br. Ceram. Trans., 94 [4] (1995). 6 P. E. Helgesen, Computer-Aided Design for Ceramic Dinnerware, Am. Ceram. Soc. Bull., 69 [1] (1990). 7 D. G. Cheshire, D. K. Harrison and P. W. Wormald, Novel Techniques for Tableware Development, pp in Proceedings of the 3rd European Conference on Rapid Prototyping and Manufacturing, Nottingham, England, A. Pareschi, Automation Trends in Modern Ceramic Industry, Ceramurgia, 19 [5] (1989) March 2001

Part VI MANUFACTURING SUPPORT SYSTEMS

Part VI MANUFACTURING SUPPORT SYSTEMS Chapters: 23. Product Design and CAD/CAM in the Production System 24. Process Planning and Concurrent Engineering 25. Production Planning and Control Systems 26. Just-In-Time