A web-based CAD/CAPP/CAM system compliant with the STEP-NC standard to manufacture parts with general surfaces

Abstract

In recent decades, there have been important advances related to information technology and manufacturing. Quality and manufacturing productivity have been improved through technologies such as multi-axis machining, high-speed machining, and ultra-precision machining. This led to significant changes in manufacturing companies that were based previously on low-cost standardized products, which started to apply elements of modern manufacturing, to provide responsiveness in a context of flexible demand. Despite advances in manufacturing technologies, the language that computer numerical control machines (CNC) use nowadays is the G-code (ISO 6983 standard), which is a set of instructions that contain the movements that the machine has to perform, without any semantic content regarding the part being processed, causing the loss of much information about the product, making it difficult or impossible to share such information across different areas of the company. In contrast, the ISO 14649 standard (known as STEP-NC) provides a high-level data model related to the manufacturing process, and it has been considered adequate to overcome the problems mentioned above. In this paper is described the methodology and implementation of a CAD/CAPP/CAM system fully compliant with the ISO 14649 standard for the design, process planning, and manufacture of parts having general shapes, and it can be executed by anyone through the Internet. The parts are built with the use of features, which can contain general surfaces, enabling the user to design complex parts. The process planning method considers the possibility of using cutting tools with different diameters for removing different amounts of material from the part. The physical STEP-NC file is generated automatically by the system, and it is used as input to the module that simulates graphically the tool paths for machining the part in a three-axis CNC machine.