Today’s manufacturing industries worldwide are facing several challenges such as shorter product life cycles, frequent design revisions, stringent demands on product quality and need for shortest time to market. Product development activities have become customer centric rather than manufacturer driven. Globalization has added a new dimension to this scenario making manufacturers to look for solutions to tap physical and knowledge resources distributed across the globe.

During the past five years, the internet has emerged as a powerful tool to enable integration of distributed data to provide collaboration and interoperability. However as of now, internet applications are mostly developed for e-commerce, facilitating communication in the form of transmission of data, pictures and videos. Realizing the potential of Internet, researchers worldwide are attempting to develop network centric CAD/CAM applications for global product development.

WebNC is an internet based product design and manufacturing system indigenously developed by Prof S S Pande and his team at Computer Aided Manufacturing Lab, Department of Mechanical Engineering, IIT Bombay.

About WebNC
WebNC is an internet based software for feature based product modeling and intelligent process planning to manufacture prismatic parts on 3 axis CNC machining centres. It caters to part shapes commonly occurring in automobile, aerospace, consumer goods and electric part manufacturing industries. Due to its Client - Server architecture, WebNC can enable integration of globally distributed product designers, process planners and remote CNC machines for collaborative product development and telemanufacturing. In addition it is an excellent didactic tool for education, training and virtual product development.

Fig. 1 shows the modular architecture of webNC system. It primarily comprises of four functional modules: communication, feature based modeler, intelligent process planning and CNC simulator.

Communication module establishes 'Anywhere Anytime' connectivity between globally distributed users clients) and CNC machines. Working on Thin Client - Thick Server architecture, it handles issues like user authentication, transfer and collaboration with remote site CNC machines for telemanufacturing. Fig. 2 shows the User Interface of webNC.

Feature Based Modeler (FBMod) provides a very user friendly graphical part modeling environment to create solid models of parts using design by features philosophy. A rich library of part feature families such as holes, pockets, slots, steps, array patterns and complex features like freeform surfaces, compound types, derived from actual industrial parts has been provided. Users can easily synthesize/edit/visualize CAD part models using the feature library provided.

Intelligent checks have been provided in FBMod for automatic validation of CAD models based on design for manufacture (DFM) strategy. Users can dynamically view the CAD models during design session using Virtual Reality (VRML) tools. Fig. 3 shows a typical design session in progress.

Intelligent Process Planning (webCAPP) module automatically generates efficient, error free CNC code from the feature based CAD model by performing four functional tasks. These are automated multi-setup planning, intelligent operation sequencing using genetic algorithms, automatic tool and process parameters selection and set up wise CNC program generation. The CNC code is post processed to FANUC and neutral data formats to enable running it on any industrial CNC machine. A customizable tool database has also been provided to suit industrial shop conditions if desired.

CNC simulator (webSIM) provides the user with a virtual CNC machining environment to graphically simulate the CNC code before running it on the machine. Fig. 4 shows typical web based CNC Simulation in progress.

Product Testing
WebNC has been extensively tested from various locations in India and abroad on typical parts taken from actual industrial shops. Part programs generated by webNC were used to cut components on CNC machines. webNC was found to generate optimum, error free CNC part programs consistently. A PC with net connection is sufficient to use webNC. No proprietary CAD/CAM software is required at the user end. This software is available for commercial use by the
industries and educational institutes.

Contact: s.s.pande@iitb.ac.in
Visit: www.me.iitb.ac.in/~sspande/