Since the birth of the world's first CNC machine tool in 1952, the development of CNC technology has been very rapid. The CNC system has also evolved from the original hard-wired CNC to today's computer numerical control (CNC). However, the modern production has higher and higher requirements for the CNC. The incompatibility between systems, programming difficulties, and low level of intelligence have greatly limited modern production and the development of CNC technology itself. At the same time, people gradually realized that the G and M codes (ISO 6983) used in CNC systems could not meet the needs of modern production and technological development. This NC program for motion and switch control limits the openness and intelligent development of CNC systems. At the same time, it also creates a bottleneck between CNC and CAX technology, which seriously hinders the development of machinery manufacturing.
In 1997, the European Community developed an object-oriented data model complying with the STEP standard through the OPTIMAL program, redefining the object-oriented data model, redefining the programming interface for milling machining, and presenting the concept of STEP-NC. STEP-NC extends the product data conversion standard STEP to the CNC field and redefines the interface between CAD/CAM and CNC. It requires the CNC system to directly use the CAD three-dimensional product data model (including geometric data, design and manufacturing features) conforming to the STEP standard (ISO 10303), plus the process information and tool information to directly generate machining programs to control the machine tool. Afterwards, STEP-NC has become a research hotspot in industrialized countries around the world. Among the most representative research projects are the STEP-NC project in Europe, the Super Modal project in the United States, and the Digital Master project in Japan. The current research on the STEP-NC project has made substantial progress. According to the prediction of the STEP Tools of the United States STEP Tools, the STEP-NC controller will appear in the first decade of this century. At that time, people will see a new perspective of automated manufacturing.
The STEP-NC data model STEP-NC is a data standard that has been redefined for the CNC system. It is based on the object-oriented form of STEP and links product design information with manufacturing information. STEP-NC defines a new STEP Application Protocol (AP-238, still in development) as a data exchange specification between CAM and CNC. AP-238 covers all the information the product needs from the concept to the finished product (parts), including 3D geometric information (AP-AP-214), process information (eg milling, car, electric discharge machining, etc.), inspection information ( AP-219) etc.
The current STEP-NC draft standard (ISO-DIS-14694) has been formed. The standards (drafts) for basic rules and milling processes have been completed, including basic concepts and rules (Part 1), general standards (Part 10), CNC milling processes (Part 11), and milling tools (Part 111). The STEP-NC standards being developed include: CNC turning (Part 12), electric discharge machining (Part 13), wood and glass processing (Part 14), and testing (Part 15). A simplified model of generic data, including parts and work plans. Workpiece refers to the final product, and the area on the work to be removed is defined by a series of processing features. The work plan includes a number of work steps (such as planes, complex surfaces, holes, etc.) that are linked to specific operations. Here the operation itself is also a concept defined in ISO-14649, design and processing methods, tools, rails, process strategies, etc.
STEP-NC-based data program structure The NC program based on STEP-NC discards the practice of programming the axes and tool actions directly in the traditional NC program. The ISO-10303 data format and feature-oriented programming principles are used. It uses the work steps as the basic unit of the process, linking features and technical information together. Each work step defines only one kind of operation ("What", "How to do it", but only one tool and one strategy). (To be continued)
In 1997, the European Community developed an object-oriented data model complying with the STEP standard through the OPTIMAL program, redefining the object-oriented data model, redefining the programming interface for milling machining, and presenting the concept of STEP-NC. STEP-NC extends the product data conversion standard STEP to the CNC field and redefines the interface between CAD/CAM and CNC. It requires the CNC system to directly use the CAD three-dimensional product data model (including geometric data, design and manufacturing features) conforming to the STEP standard (ISO 10303), plus the process information and tool information to directly generate machining programs to control the machine tool. Afterwards, STEP-NC has become a research hotspot in industrialized countries around the world. Among the most representative research projects are the STEP-NC project in Europe, the Super Modal project in the United States, and the Digital Master project in Japan. The current research on the STEP-NC project has made substantial progress. According to the prediction of the STEP Tools of the United States STEP Tools, the STEP-NC controller will appear in the first decade of this century. At that time, people will see a new perspective of automated manufacturing.
The STEP-NC data model STEP-NC is a data standard that has been redefined for the CNC system. It is based on the object-oriented form of STEP and links product design information with manufacturing information. STEP-NC defines a new STEP Application Protocol (AP-238, still in development) as a data exchange specification between CAM and CNC. AP-238 covers all the information the product needs from the concept to the finished product (parts), including 3D geometric information (AP-AP-214), process information (eg milling, car, electric discharge machining, etc.), inspection information ( AP-219) etc.
The current STEP-NC draft standard (ISO-DIS-14694) has been formed. The standards (drafts) for basic rules and milling processes have been completed, including basic concepts and rules (Part 1), general standards (Part 10), CNC milling processes (Part 11), and milling tools (Part 111). The STEP-NC standards being developed include: CNC turning (Part 12), electric discharge machining (Part 13), wood and glass processing (Part 14), and testing (Part 15). A simplified model of generic data, including parts and work plans. Workpiece refers to the final product, and the area on the work to be removed is defined by a series of processing features. The work plan includes a number of work steps (such as planes, complex surfaces, holes, etc.) that are linked to specific operations. Here the operation itself is also a concept defined in ISO-14649, design and processing methods, tools, rails, process strategies, etc.
STEP-NC-based data program structure The NC program based on STEP-NC discards the practice of programming the axes and tool actions directly in the traditional NC program. The ISO-10303 data format and feature-oriented programming principles are used. It uses the work steps as the basic unit of the process, linking features and technical information together. Each work step defines only one kind of operation ("What", "How to do it", but only one tool and one strategy). (To be continued)
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