Knowledge-based Engineering complements traditional CAD/CAM systems to provide a new strategic approach for improving effectiveness in eManufacturing. DEEPAK SHIKARPUR explains what KBE is all about and opines that KBE is becoming an essential part of strategy as manufacturing companies struggle to respond to global competitive pressures

Today’s economy presents a new set of challenges for the manufacturing industry. Global competition has empowered customers who now constantly demand new and better quality products. Design-to-delivery cycle time is rapidly collapsing along with prices and margins, which is hurting RoI. As a result of all this, businesses are forced to increase customer and market focus and leverage seamless technology solutions to stay competitive. Organisations engaged in discrete manufacturing have problems in managing the design-to-delivery life cycle of the product. The cycle starts with concept design of the product, which is where abstract ideas are tried and tested.

Current CAD/CAM technologies do not address the requirements of the integrated design engineering process completely. All too often, the CAD model is merely a geometric interpretation of the design intent. Design iteration is achieved by iterative procedures that are cumbersome and inevitably stretch design timescales. In today’s dynamic marketplace, customer needs and specifications change often and as a result ‘Change Management’ becomes an issue. Version control of changes and mapping them across from design to manufacturing is where IT can be used innovatively to gain competitive edge.

Knowledge-based Engineer-ing (KBE) offers a significant advantage over current CAD/CAM technologies because the fundamental element is not geometry but a rule. Rules are used to describe the knowledge about the product, the technologies used to design, analyse and manufacture it. Rules can be in the form of physical equations, graphical and tabular relationships and even anecdotal ‘rules of thumb’, which reflect years of design experience but which defy a more rational relationship. This is where an artificial intelligence approach can be leveraged.

KBE and objects
The underlying basis of a KBE system is an object-oriented structure. An object is an assembly of rules that can create and store data, and relate data to other objects. The definition of an object is self-contained and can be developed and tested in isolation. The same object can be re-used in many different contexts.

Unlike conventional computing environments, it is not necessary to flow chart the order in the engineering process. KBE only requires description of the individual objects required to define the solution. The order of solution is demand driven and hence is worked out by the KBE system in response to user inputs. The rules provide a generic description, which is used to drive the design engineering process.

What KBE achieves
The KBE system can model the complete design process, integrating analysis and manufacturing considerations, with design geometry. It can be defined as an engineering method in which knowledge about the product and the techniques used to design, analyse and manufacture a product are stored as a series of “rules.”

KBE creates a design that is, therefore, a single instance of a generic definition and can adopt its geometric representation to suit the requirements of analysis and manufacture and react rapidly to fundamental design changes.

Knowledge-based Engineer-ing extends the product design process beyond geometric modelling to capture the knowledge of a company’s most important asset—the experience of its engineers. Unlike CAD systems that manipulate mainly geometric information, KBE systems capture the engineering intent behind the product—the how and why aspects of the design.

A KBE system stores knowledge about a product in a comprehensive product model composed of engineering rules that describe how products are designed, analysed and manufactured. These rules can be design rules, standard engineering rules, or experiential rules of thumb about attributes of the physical product such as geometry, material type. The model created by the rules is similar to a spreadsheet and allows engineers to quickly evaluate many design alternatives or create new designs by altering the input parameters or the rules, dramatically improving the productivity and ensuring consistently high product quality.

Another strategic benefit of KBE is that the product model also includes various outputs such as reports of engineering results, data of engineering analysis, 3D geometric models, and manufacturing instructions. When the design changes, so do the outputs. Information is always up-to-date and reflects the current state of the design, automatically.

Strategic benefits
More companies are turning to KBE systems to help them respond to worldwide competitive pressures.
With CAD systems, people define part geometry and document the result of the design process with annotated drawings. KBE systems complement CAD systems by adding the engineering knowledge that drives the product design process. They also produce other information besides drawings such as Bills of Material, cost analysis, process plans, MRP inputs and user-defined reports. Companies can use CAD systems as either the front-end to supply geometric constraints or other user specifications to a KBE system, or as a back-end for detailing, documentation, analysis and NC tool path generation.

Who needs KBE?
Companies with complex design and manufacturing problems will benefit the most from KBE. Many of the leading aerospace, automotive, consumer products, defence and industrial equipment manufacturers have installed KBE systems to help them reduce time-to-market and capture valuable engineering knowledge within the company. Complex designs that require much iteration for optimisation and designs with a high degree of repetition are perfect candidates for KBE.