Papers by Keyword: STEP-NC

Abstract: STEP-NC is a new data model for data exchange between CAD / CAM and CNC, which provides rich information for CNC machine tools and tells CNC “what to do”rather than “how to do”, overcomes many shortcomings of the traditional G&M codes and has become a hot research issue now. How to efficiently and cost-effectively generate the STEP-NC program is a very crucial problem. Although some domestic scholars have done some research about STEP-NC program generation, most of them do second development base on ST-Developer software. The paper developed a STEP-NC program generation module by using the VC++6.0 and CAD / CAM software. The module can read AP203 file generated by CAD system, identify manufacturing features according to its geometry information and conduct process planning to generate STEP-NC file according to ISO14649 standard. This module has been proved effectively by an instance.

Abstract: A method and prototype system have been developed to assess manufacturability of a machining job with a known machine tool. The data for describing the machining task confirms to STEP-NC data model, i.e. ISO 14649. A group of manufacturability indices have been suggested used in the system. They are called “Key Manufacturability Indicators” (KMIs). Examples of KMIs are workpiece clamping data, machine tool’s capability and cutting tool information. To assist the evaluation process, a machine tool data model is used. The prototype system is validated through an example.

Abstract: Numerical controlled milling is widely used in the manufacturing industry because of its high productivity and workpiece surface quality. The aim of this work is to establish a methodology to evaluate the rough machining time and to predict optimal values of cutting speed to minimise machining time of circular cavity, during high speed milling. The circular cavity is divided into volumes distributed according to the real radial depth. The obtained results show that the proposed method is consistent with the actual situation.

Abstract: STEP-NC is used to transfer machining data between STEP-NC compliant Computer Aided Design (CAD), Computer Aided Manufacturing (CAM) and Computer Numerical Controller (CNC). It overcomes G&M code weakness which has thousand lines of codes but none of them define the machining process. In order to create a complete chain of STEP-NC system to be a new way of producing product in manufacturing environment, a new CNC machine and CAM software that are compliant to STEP-NC has to be developed. Internationally the research and development of STEP-NC has gain many achievement until now, but there is still no commercial STEP-NC system that are fully working in producing variety of features. This research focusing on the software development, named as GEN-M. The software that has been successfully developed are capable to generate code for drilling referring to selected case study from Annex F (Example 1) in ISO 14649 Part 11.

Abstract: Since G-codes have been proved limiting the modern manufacturing industry, ISO14649 was put forward. This paper presents a solution to generate ISO14649 files for circuit board milling. The process planning is given, and all the processes needed are contained in the ISO14649 file. Features and machining operations are identified for each process, such as the closed pocket having a “General_closed_profile” attribute and bosses, round holes, slots, the planar face, contour parallel strategy, contour bidirectional strategy and etc. The scenario of one feature with multi tools are put forward to promote the milling efficiency and an entity “Combined_Machining_workingsteps” is proposed. Besides, some other extensions are made, such as entities for representing circuit geometries in machining features. Algorithms for tool paths generation are demonstrated for contour parallel milling and bidirectional milling, where a new algorithm based on pixels is used. The new algorithm can be used in other functions such as detecting uncut regions.

Abstract: With STEP-NC providing a way for seamless integration of the design, manufacturing, and quality control processes, the implementation of in-process measurement in this context has become a necessity for STEP-compliant NC manufacture. In the light of current research and development trends in this field, this paper proposes an approach to on-machine planning for in-process measurement, focusing on touch probing operations. Issues about the measured elements and the probing path planning are mainly addressed, and a prototype system is designed and implemented, which generates probing paths based on the information contained in the STEP-NC part program. The feasibility of the proposed approach is demonstrated with an example STEP-NC file.

Abstract: STEP-NC standard contains information on how CNC machine tools can be represented from STEP product data model. STEP-NC is an extension of STEP which is the standard for exchange product model data. This determines the neutral data format for digital information from a product. This paper is to propose an architecture of intelligent controller via multi-agent-based conceptual as the reference architecture. It can be successfully used to create an open CNC on ISO standard of ISO 14649 and ISO 10303. This offers interoperability, portability, and adaptability. The proposed framework consists of four main modules, STEP-NC interface, simulator, data warehouse, and communication. In order to optimize, the controller should incorporate with various technology related to intelligent, such as kernel software, open communication port and open hardware design. The architecture will be implemented in CNC controller and to be tested later on actual milling machine. It will simplify the design of CNC machine controller with the architecture layers responsible for data processing, data storage, execution and feedback. This paper will discuss order towards the requirements for global interoperable manufacturing for real-life machining system.

Abstract: Today with the latest technology the information beyond tool movement and switching instruction such as tooling, manufacturing features and process sequences are needed to support global adaptability for manufacturing with a specific focus on CNC-based manufacture This research focuses on the use of the new standard; ISO 14649 (STEP-NC), to address the process planning and machining of discrete turn/mill components and proposes a STEP Compliant NC structure for generation of ISO 14646 code which can be used for turned component manufacture. The novel application of this work is STEP-NC compliant process control where the research will utilise and extend the standard for in process measurement at the machine and also explore the application and integration of the STEP-NC standards. The major contribution of this research is the review of a computational environment for a STEPNC compliant system for turn/mill operations.

Abstract: STEP-NC (ISO 14649) is a newly developed and feature-based machine tool control language for CNC controller. In contrast with conventional G&M code (ISO 6983), this new data model could almost transmit all the designing and planning information for machining parts through CAD&CAPP&CAM to CNC. However, STEP-NC is feasible but not enough to support some intelligent actions such as self-planning, self-learning, decision-making, etc. A complete and well-structured knowledge base is urgently needed to be established to support CNC intelligence. The main work of this paper is focused on two fields: i) An extraction, presentation and utilization mechanism for ontology-based machining knowledge is implemented. ii) A novel framework for STEP-Compliant and knowledge-base supported intelligent CNC controller is proposed.

Abstract: In conventional machining of free form surfaces, incomplete information exchange between CNC and CAD/CAM results in many limitations need to be rectified. In the paper, a new structure of CNC based on STEP-NC is proposed. A 5-axis real-time interpolator for NURBS surfaces machining is realized. A STEP-NC controller has been developed, which is a software modular CNC system. The CNC system has been installed on a tilt-rotary type 5-axis machine tool. The milling experiment has been performed.