Shop-floor Programming Research Articles

Development of standardized tools for shopfloor programming of turning and turn-milling machines

The problems of using CAM-applications for shop floor programming are studited. The reasons of problems of transfer of the created control programs from one CNC systems to another are revealed. A solution for unifying the format of recording of machine cycles is proposed and its applying for different CNC systems is demonstrated..

Developing ISO 14649-based conversational programming system for multi-channel complex machine tools

A multi-channel complex machine tool (MCCM) is a versatile machining system equipped with more than two spindles and turrets for both turning and milling operations. Despite the potential of such a tool, the value of the hardware is largely dependent on how the machine tools are effectively programmed for machining. In this paper we consider a shop-floor programming system based on ISO 14649 (called e-CAM), the international standard for the interface between computer-aided manufacture (CAM) and computer numerical control (CNC). To be deployed in practical industrial usage a great deal of research has to be carried out. In this paper we present: 1) Design consideration for an e-CAM system, 2) The architecture design of e-CAM, 3) Major algorithms to fulfill the modules defined in the architecture, and 4) Implementation details.

Architecture and implementation of a shop-floor programming system for STEP-compliant CNC

STEP-NC (formalized as ISO 14649 and ISO 10303 AP238) is a new interface (or language) standard for the CAD–CAM–CNC chain, currently under establishment by ISO TC184 SC1 and SC4. Upon completion, it will replace ISO 6983, so called M & G codes used for CNC since 1950s. As the new language is being established, a new CNC controller called STEP-CNC (STEP-compliant CNC), capable of carrying out various intelligent tasks using the new language as an input, receives worldwide attention. Shop-floor programming (SFP) system is a computer-assisted part programming system interfaced with STEP-CNC. Its primary function is to generate part program in ISO 14649 (or STEP AP238) to machine the part geometry given by STEP AP203 or AP224 file. In this paper, we first present an architecture for the SFP system, followed by implementation technology including: (1) STEP physical file interpretation, (2) feature recognition, (3) process planning, (4) part program generation, and (5) verification. The developed methodology was implemented in a prototype called PosSFP, and tested with Korea STEP-NC system.

Aerospace subcontractor benefits from shop floor programming

Aerospace subcontractor benefits from shop floor programming

Developing an integrated STEP-compliant CNC prototype

Abstract STEP-compliant CNC is the next-generation CNC controller, taking the STEP-NC data model as the interface scheme between CAM and CNC and carrying out various intelligent functions. At the moment, efforts are being made worldwide to establish an international standard for the new interface scheme (so-called STEP-NC), formalized as ISO 14649. In the near future, the new interface scheme will be completed and announced as the international standard. Upon completion, the standard will replace the conventional scheme based on ISO 6983, so-called M&G codes. Further, the new interface scheme will impact the CAD-CAM-CNC process chain and the advancement of the CNC controller. This paper develops an integrated STEP-compliant CNC system (or STEP-CNC) based on the new interface scheme. The system is composed of five modules: (1) Shop Floor Programming System (PosSFP), (2) Tool Path Generator (PosTPG), (3) Tool Path Viewer (PosTPV), (4) Man Machine Interface (PosMMI), and (5) CNC Kernel (PosCNC). The developed system is a prototype but very comprehensive, including all the modules required for realizing “art-to-part” through the new CAD-CAM-CNC chain. Architecture and functional details are presented together with a realistic demonstration.

Shopfloor programming — a concept supporting skill-based manufacturing

German-speaking countries have a long tradition of skill-based manufacturing. Within the German dual system of vocational training, production workers are provided with a high degree of qualifications, experience, and skills. Nowadays, however, advances in technology and the increasing use of numeric control for machine tools and other types of production machinery are major factors endangering this tradition. It is therefore of particular interest to investigate the extent to which forms of shopfloor programming are applied which can help to stabilize or even increase production workers' skills and qualifications, thus preserving their ability to work autonomously.

Use of CNC and alternative methods of work organization

Since the introduction of NC technology for manufacturing systems nearly 40 years ago, technological progress has offered an increasingly wide scope for the organization of work with NC machines. Formerly, hardwired NC controllers largely required programming away from the shopfloor, whereas modern CNC technology can be operated with various types of shopfloor programming. With regard to a number of surveys carried out in the German mechanical engineering industry in recent years, different forms of work organizations with CNC machine tools can be seen. One can roughly differentiate between ‘centralistic’ and ‘shopfloor-oriented’ strategies. The reasons for alternative forms of work organization can be found first in technical and economic factors, and second, the type of work organization selected by firms for the use of CNC machine tools is to a large extent determined by social and political factors.

Obstacles to Shop-Floor CNC Programming in the United States

The implementation of skill-based approaches to technological development face several obstacles in the United States. This paper explores three of these obstacles in the context of attempts to implement shop-floor programming of CNC machine tools: 1) Software design, 2) Orientation of training programs, and 3) Social issues of control. Discussion of these obstacles are presented in relation to the authors experiences in conducting the Shop-Floor Programming Project at the University of Lowell. Skill-based approaches which allow the voice of skilled production workers to influence the development of new technologies can lead to improved over-all working life. Solutions to over-come the obstacles associated with skill-based automation requires further investigation into the social issues underlying both the design and implementation of process technologies.

Criteria for selecting control systems in flexible manufacturing

Industry in Europe has been undergoing major structural changes during the last twenty years or so. Against the background of high demand for consumer and capital goods with corresponding, mostly fixed production capacities, it was necessary to build flexible and, at the same time, efficient production plants in order to cope with the increasing variety of products and shorter innovation cycles. Flexible manufacturing is inconceivable without information technology. Thus, the word “information” has rightly taken its place in the list of primary factors associated with modern production technology. The “gating” of data into production planning and quality assurance, combined with concepts of logistics and control, keeps the flow of materials on the move and helps to shorten lead times. The organization of production and the plant equipment itself have to be matched to the size of the plant, the product range and the market. In large-batch production, for example, a customized vehicle is required; in small-batch or unit production it is often necessary to manufacture a machine to specific customer requirements. Despite such great variations in the type of requirement, it is still possible to distinguish a number of common factors—one of them being the hierarchical structure of the automation landscape with objective and transparent distribution of information across all levels; from the control level for pre-production, assembly and transport up to the planning level for capacity planning and materials management. Hierarchical levels enable particular tasks to be assigned to specific automation equipment. Mainframes and minicomputers are used at the planning level. Dedicated systems such as numerical controls and programmable controllers are now used almost exclusively on the shopfloor control level. Local area networks connect the automation systems of different manufactures without the need for any adaptation. Protocols must be unified for this purpose. Since stable standards are not yet in existence, Siemens has decided to follow the strategy of standard harmonized development. Programmable controllers are part of all production, transport and storage systems. The main requirements are for control, operator communication, monitoring, counting and positioning. A comprehensive production family is a very important factor. Excellent hardware compatibility, easy interlinking and a uniform programming language are all characteristic of the family philosophy. Industrial robots are used mainly in the automobile industry. Largely thaks to them it is possible to produce economically and rationally any mix of model variants and to automate assembly. Programming facilities such as teach-in, on-line or off-line are therefore an important selection criterion for robot control. The majority of numerical controls in use today are used for controlling single machines in heavy-duty and special-purpose machinery manufacture. In networked applications, numerical controls form part of flexible manufacturing systems. In addition to machine control and management, the capacity for communication is an important criterion for selection in this case. In many controls for individual machines the priority is for quick and easy programming. “Shopfloor programming” has assumed considerable importance in such applications. Shopfloor programming requires controls with a sophisticated, user-friendly, graphics interface. Examples show how dedicated automation subsystems have been finding widespread application in the automation of manufacturing, transport and warehouse equipment. They are designed specially to perform certain tasks, both in programming and operation, in order to provide an economic solution to a problems in terms of matched performance and functionality.

In search of the computer-aided craftsman

Profound changes in world markets are resulting in conflict between traditional structures of production and new market requirements. The right answers to this challenge are heavily disputed. One option is to replace human work still further by artificially intelligent technology without changing basic structures of production. In contrast to this strategy, alternative production concepts seek to combine the unique human capabilities of perception, evaluation and decision making in unstructured situations with appropriately designed computer systems. Empirical evidence from the use of NC technology indicates that sensual experience and practical knowledge are necessary ingredients rather than disappearing residuals of efficient production. By far their tacit dimension does not allow complete transformation into objectified, scientific knowledge. In the field of metal cutting it is the skilled workers themselves who constitute the primary source of productivity. In order to overcome their traditionally problematic and uncomfortable working situation, shop-floor programming methods have been developed that are adapted to their concrete and graphic mode of thinking and acting. These allow workers to make their own efficient NC programs, thus maintaining their practical competence. This paper illustrates a necessary new perspective in system design: away from developing computer programs for imitating and replacing human expertise and towards designing computers as a useful tool for human experts.

Precision Subcontractor Opts for DNC Instead of Shop Floor Programming

OF six CNC machine tools linked through RS 232 interfaces into a direct numerical control (DNC) and automatic off‐line programming system at Tufflay Precision Engineering's Woking factory, three are Hitachi Seiki machines — two multi‐purpose vertical machining centres and a CNC lathe — supplied by Tarex Berger & Associates Ltd, Egham.