- Email: [email protected]
Joint Anglo-Hungarian seminar on computer aided geometric design
Computers in Industry The Following lectures were also presented at AUTOFACT 4: "The Management and Planning of an Integrated CAD/CAM System" (J.H. Keller, Rockwell International Corporation, Canoga Park, Calif.) "The Future of Data Highways in Factory Automation" (A. Beavers, General Electric Company, Charlottesville, Va.) "The Robot in the Automated Factory - a 1982 Update" (R. Green, Prab Robots, Inc., Kalamazoo, Mich.) "Computer-Aided Mold Manufacturing: One Point of View" (R.A. Tomisak, UFE Incorporated, Stillwater, Minn.) "Shop Floor Information System Design and Implementation" (G.L. Berry, Garrett Turbine Engine Company, Phoenix, Ariz.) "CAEDOS - Computer Aided Engineering Documentation System - Justifications" ( D. Christensen and B. Hill, Naval Weapons Center, Chinal Lake, Calif.) "Computer Integrated Manufacturing, Its Application and Justification" (E.J. Adlard, Metcut Research Associates, Inc., Cincinnati, Ohio) "DNC - Extending CAD/CAM to the Shop Floor" (J.C. Bergeron, Gerber SystemsTechnology, Inc., South Windsor, Conn.) "An Overview of Solids Modelling Systems" (J. Borrell, Computer Graphics World, San Francisco, Calif.) "Electro-Optics for Gauging Inspection and Robotics in the Industrial Environment" (W.,L Pastorius, Diffracto Ltd., Detroit, Mich.)
Conference Reports
193
"Closing the Loop on Propeller Manufacturing and Repair Processes" (R. Wells, NAVSEA, Arlington, Va.) "Managing Process Control" (H.J. Bajaria, Multiface, Inc., Dearborn Hts., Mich.) "Practical Approach to AS/RS Control Systems Design" ( E.J. Budhill, Hartmann Material Handling Systems, inc., Victor, N.Y.) "Modal Analysis for Managers" (C. Van Karsen, Structural Kinematics, Warren, Mich.) "Fully Integrated CAD/CAM for Roll Tooling Design and Manufacture" (D.A. Sellens, The Bradbury Co., Inc., Moundridge, Kansas) "Artificial Intelligence for Robots and Machine Tools in the Factory of the Future" (J.M. Vranish, Naval Surface Weapons Center, White Oak, Silver Spring, Md.)
The Proceedings of AUTOFACT 4 have been published by the Society of Manufacturing Engineers, P.O. Box 930, Dearborn, Michigan 48128, U.S.A. Outside the U.S.A. and Canada, the Proceedings are available from North-Holland Publishing Company, P.O. Box 211, 1000 AE Amsterdam, The Netherlands. 1982. ISBN 0-87263-093-5. US $60.00 (USA/Canada); Dfl.225.00 (Rest of the World).
Joint Anglo-Hungarian Seminar on Computer Aided Geometric Design As part of the recently established collaborative project between Cambridge, Cranfield and Budapest on theoretical topics in Computer Aided Geometric Design, a three-day Seminar was held at the Computer and Automation Institute (CAI), Budapest, on October 2 7 - 2 9 , 1982 In his opening speech, Academician T. V~mos the director of CAI and current President of the International Federation of Automatic Control (IFAC) recalled the historic links between Britain and Hungary and also reminded the more than 80 participants, that the first Joint Seminar on CAD had been arranged just 10 years before by the Computer Aided Design Centre of Cambridge and CAl. The present Seminar was primarily aimed at mutually presenting the current research work conducted in this area at Cranfield Institute of Technol-
ogy (CIT), Department of Mathematics, Cambridge University Engineering Department (CUED) CAD Group and Computer and Automation Institute, Mechanical Engineering Automation Division. I n his i n t r o d u c t o r y talk Dr. J. H a r v a n y presented his ideas o n modelling in C A D , which can be s u m m a r i z e d as follows. " M o d e l s are abstractions which are used to represent certain selected aspects of reality - never its totality. I n the course of various phases of design, a succession of models is used, c o r r e s p o n d i n g to the aspect of the design object currently b e i n g treated (e.g. its thermal, kinematic, static, aesthetic, dynamic, etc. properties). O n e of the most challenging p r o b l e m s today is to m a i n t a i n the consistency of design data developed through various models of the same object.
194
Conference Reports
In mechanical engineering, the new techniques of volumetric modelling show promise of helping to overcome this problem. They are not, however, a panacea and their use - like that of any other technique - is subject to an engineering appraisal of their appropriateness to the problem in hand." Dr. M.J. Pratt from CIT gave a brief review of the IGES format for transmission of graphical data between different C A D / C A M systems. An extension of the IGES standard developed by CAM-I was described which permits transmission of 3D data between geometric modellers. Results of a recent survey carried out Cranfield on industrial requirements for the inclusion of free-form surfaces and related features in the transmission format was also discussed. Dr. M. B/tthor (CAI) presented a 3D geometric modeller and animation system with applications in robotics. The minicomputer system consists of two main packages. The first is an interactive geometrical modelling system for creating 3D computer models having planar and curved surfaces. The other main component is a motion simulator which computes the relative motion of a number of objects and displays them in any phase of the motion using hidden-line elimination. An application example used in robot programming was presented. Mr. G.E.M. Jared (CUED) gave a brief historical review of the development of the BUILD geometric modeller starting from the early 70's. Some details of the functions and the features of the current system were described and an indication was given of the likely future developments of BUILD. Dr. T. Vhrady (CAI) briefly reviewed the stateof-the-art in volumetric and surface modelling. After summarizing the most significant deficiencies of both disciplines, the conditions for a synthesis were given. Some novel attempts to bridge the gap and the recent sculptured surface facilities with double-quadrative surfaces in BUILD-3 were also discussed, including the most important features of double-quadratic patches. Mr. T. Parkinson, in his talk on "Geometric model - a data-base for computer aided NC-tape generation and process planning", presented the algorithms developed by Grayer in his work on NC-tape generation for 2.5D objects, along with the planned extensions to his work, which will .make it possible to generate tapes for the full
(.repute,'., :.. lndusir~
range of BUILD curves and surfaces. He also dealt with computer aided process planning schemes. The shape feature recognition aspect of Kyprianou's work on automatic part-classification was described. This is particularly relevant to the semi-generative approach to computer aided process planning. After a brief introduction of CAD at Cambridge University, Mr. B. Wrrdenweber (Cambridge, Computer Laboratory) described the recent work on applications of geometric modelling. This included fast picture generation for 3D solids and automatic mesh generation for finite element analysis. An algorithm was presented for the decomposition of two and three dimensional polyhedra. This enables fast conversion of geometric representation between a modeller and applications. Mr. B. Ga/tl presented the F F S - C A D / C A M system for designing and manufacturing sculptured surfaces, which was developed at CAI. After a short, general description of the system facilities. some practical questions of shape definition, shape modification and certain implementational problems were discussed in detail. Mrs. L.K. Bruckner (CAI) went on discussing the F F S - C A D / C A M system by focusing on the automatic NC-tape generation side. The roughing subsystem generates NC-tape for 2.5D machining by a cylindrical cutter following a terracing strategy. This talk described the three stages of the roughing process starting from planar intersection curves: offsetting, concatenation of offset curves, and toolpath generation. The relevant problems were mathematically formulated and the correctness of the algorithms was proved. Dr. Gy. Kov/lcs (CAI) presented the Unified Cutting Technology Planning System (UCTPS), which is a joint work of the COMECON countries to furnish a computer aided design tool for cutting technologies. The basic parts of the system serve for geometry design, tool selection, process planning, technology design and NC tape generation. A crucial and most up-to-date part of the UCTPS is the 3D subsystem to design the geometry and cutting technologies of translational and sculptured surfaces. This contribution dealt with the structure and main characteristics of UCTPS, and then a detailed description of translational surface design was given. After the mathematical definitions, the program modules for geometry descript
Computers in lndustry
tion and cutting technology design were discussed. Finally, some part-programs and resulting tool paths were demonstrated. All participants agreed that the exchange of ideas was very useful and it is hoped that further Joint Seminars will be held in the coming years. The proceedings of the Seminar, edited by G.E.M. Jared
ConferenceReports
195
(Cambridge) and T. V~rady (Budapest), will be published both in Cambridge and Budapest. Tam~s Varady (CAI) Computer and Automation Institute Hungarian Academy of Sciences Budapest Hungary
Flexible Manufacturing Systems The 1st International Conference on Flexible Manufacturing Systems, sponsored and organized by IFS Conferences Ltd., was held in Brighton, U.K. from October 20-22, 1982. Participating sponsors included the British Robot Association, the Department of Industry (U.K.), the Production of Engineering Research Association (U.K.), FMS Magazine (U.K.), the Institute for Production and Automation (IPA) (Stuttgart, West Germany) and the Computer and Automated Systems Association of the Society of Manufacturing Engineers (U.S.A.). We present below, a report on the lectures delivered at this conference.
Automation or Liquidation L. Wood (GEC Electrical Projects Ltd.) suggested that without flexible automation, liquidation will inevitably follow. The timing of such an unhappy event depends on the competition; whether this is to be in a national sense, by competition from low labor rates of developing countries manufacturing ordinary everyday goods, or in a company sense where direct competitors at home or abroad are using techniques to make their businesses slimmer and more competitive. Wood used the expression "flexible automation" in a business sense, i.e. a means of making money. An alternative title for his lecture is "The Application of Automation to a Flexible Manufacturing System will Prevent Liquidation". Principles of Flexibility According to J.A. Buzacott (University of Toronto, Canada), "flexibility" is the essential fea-
ture of flexible manufacturing systems. One measure of flexibility, job flexibility, relates to the mix of jobs which the system can process. In general, productivity tends to decline with increasing job flexibility. Another measure of flexibility, machine flexibility, relates to the effect on the system of internal disturbances such as breakdowns. Machine flexibility can, with appropriate design and operation of the system, increase with increasing job flexibility. This suggests that for maximum performance there is an optimum degree of job flexibility. Buzacott proposed a number of principles for ensuring that the performance of an FMS is maximized. Status in Japan In Japan, efforts have been devoted to the embodiment of potentiality of flexible manufacturing systems to cope with the growing demand for the effective small batch production. Considering the increasing importance of the FMS, it is of great interest to study and overview the FMSs that are in practical use. T. OhmL Y. Yoshida (Mechanical Engineering Laboratory, Japan) and Y. Ito (Tokyo Institute of Technology, Japan) presented the results of a survey study on the FMS being implemented in Japan. By showing the statistical data on their dominant characteristics, they clarified the present status and trends. Developments in Japan An assessment of the developments of FMS in Japan was made by J.A.G. Knight (University of Nottingham, U.K.), based on information gained
Conference Reports
193
"Closing the Loop on Propeller Manufacturing and Repair Processes" (R. Wells, NAVSEA, Arlington, Va.) "Managing Process Control" (H.J. Bajaria, Multiface, Inc., Dearborn Hts., Mich.) "Practical Approach to AS/RS Control Systems Design" ( E.J. Budhill, Hartmann Material Handling Systems, inc., Victor, N.Y.) "Modal Analysis for Managers" (C. Van Karsen, Structural Kinematics, Warren, Mich.) "Fully Integrated CAD/CAM for Roll Tooling Design and Manufacture" (D.A. Sellens, The Bradbury Co., Inc., Moundridge, Kansas) "Artificial Intelligence for Robots and Machine Tools in the Factory of the Future" (J.M. Vranish, Naval Surface Weapons Center, White Oak, Silver Spring, Md.)
The Proceedings of AUTOFACT 4 have been published by the Society of Manufacturing Engineers, P.O. Box 930, Dearborn, Michigan 48128, U.S.A. Outside the U.S.A. and Canada, the Proceedings are available from North-Holland Publishing Company, P.O. Box 211, 1000 AE Amsterdam, The Netherlands. 1982. ISBN 0-87263-093-5. US $60.00 (USA/Canada); Dfl.225.00 (Rest of the World).
Joint Anglo-Hungarian Seminar on Computer Aided Geometric Design As part of the recently established collaborative project between Cambridge, Cranfield and Budapest on theoretical topics in Computer Aided Geometric Design, a three-day Seminar was held at the Computer and Automation Institute (CAI), Budapest, on October 2 7 - 2 9 , 1982 In his opening speech, Academician T. V~mos the director of CAI and current President of the International Federation of Automatic Control (IFAC) recalled the historic links between Britain and Hungary and also reminded the more than 80 participants, that the first Joint Seminar on CAD had been arranged just 10 years before by the Computer Aided Design Centre of Cambridge and CAl. The present Seminar was primarily aimed at mutually presenting the current research work conducted in this area at Cranfield Institute of Technol-
ogy (CIT), Department of Mathematics, Cambridge University Engineering Department (CUED) CAD Group and Computer and Automation Institute, Mechanical Engineering Automation Division. I n his i n t r o d u c t o r y talk Dr. J. H a r v a n y presented his ideas o n modelling in C A D , which can be s u m m a r i z e d as follows. " M o d e l s are abstractions which are used to represent certain selected aspects of reality - never its totality. I n the course of various phases of design, a succession of models is used, c o r r e s p o n d i n g to the aspect of the design object currently b e i n g treated (e.g. its thermal, kinematic, static, aesthetic, dynamic, etc. properties). O n e of the most challenging p r o b l e m s today is to m a i n t a i n the consistency of design data developed through various models of the same object.
194
Conference Reports
In mechanical engineering, the new techniques of volumetric modelling show promise of helping to overcome this problem. They are not, however, a panacea and their use - like that of any other technique - is subject to an engineering appraisal of their appropriateness to the problem in hand." Dr. M.J. Pratt from CIT gave a brief review of the IGES format for transmission of graphical data between different C A D / C A M systems. An extension of the IGES standard developed by CAM-I was described which permits transmission of 3D data between geometric modellers. Results of a recent survey carried out Cranfield on industrial requirements for the inclusion of free-form surfaces and related features in the transmission format was also discussed. Dr. M. B/tthor (CAI) presented a 3D geometric modeller and animation system with applications in robotics. The minicomputer system consists of two main packages. The first is an interactive geometrical modelling system for creating 3D computer models having planar and curved surfaces. The other main component is a motion simulator which computes the relative motion of a number of objects and displays them in any phase of the motion using hidden-line elimination. An application example used in robot programming was presented. Mr. G.E.M. Jared (CUED) gave a brief historical review of the development of the BUILD geometric modeller starting from the early 70's. Some details of the functions and the features of the current system were described and an indication was given of the likely future developments of BUILD. Dr. T. Vhrady (CAI) briefly reviewed the stateof-the-art in volumetric and surface modelling. After summarizing the most significant deficiencies of both disciplines, the conditions for a synthesis were given. Some novel attempts to bridge the gap and the recent sculptured surface facilities with double-quadrative surfaces in BUILD-3 were also discussed, including the most important features of double-quadratic patches. Mr. T. Parkinson, in his talk on "Geometric model - a data-base for computer aided NC-tape generation and process planning", presented the algorithms developed by Grayer in his work on NC-tape generation for 2.5D objects, along with the planned extensions to his work, which will .make it possible to generate tapes for the full
(.repute,'., :.. lndusir~
range of BUILD curves and surfaces. He also dealt with computer aided process planning schemes. The shape feature recognition aspect of Kyprianou's work on automatic part-classification was described. This is particularly relevant to the semi-generative approach to computer aided process planning. After a brief introduction of CAD at Cambridge University, Mr. B. Wrrdenweber (Cambridge, Computer Laboratory) described the recent work on applications of geometric modelling. This included fast picture generation for 3D solids and automatic mesh generation for finite element analysis. An algorithm was presented for the decomposition of two and three dimensional polyhedra. This enables fast conversion of geometric representation between a modeller and applications. Mr. B. Ga/tl presented the F F S - C A D / C A M system for designing and manufacturing sculptured surfaces, which was developed at CAI. After a short, general description of the system facilities. some practical questions of shape definition, shape modification and certain implementational problems were discussed in detail. Mrs. L.K. Bruckner (CAI) went on discussing the F F S - C A D / C A M system by focusing on the automatic NC-tape generation side. The roughing subsystem generates NC-tape for 2.5D machining by a cylindrical cutter following a terracing strategy. This talk described the three stages of the roughing process starting from planar intersection curves: offsetting, concatenation of offset curves, and toolpath generation. The relevant problems were mathematically formulated and the correctness of the algorithms was proved. Dr. Gy. Kov/lcs (CAI) presented the Unified Cutting Technology Planning System (UCTPS), which is a joint work of the COMECON countries to furnish a computer aided design tool for cutting technologies. The basic parts of the system serve for geometry design, tool selection, process planning, technology design and NC tape generation. A crucial and most up-to-date part of the UCTPS is the 3D subsystem to design the geometry and cutting technologies of translational and sculptured surfaces. This contribution dealt with the structure and main characteristics of UCTPS, and then a detailed description of translational surface design was given. After the mathematical definitions, the program modules for geometry descript
Computers in lndustry
tion and cutting technology design were discussed. Finally, some part-programs and resulting tool paths were demonstrated. All participants agreed that the exchange of ideas was very useful and it is hoped that further Joint Seminars will be held in the coming years. The proceedings of the Seminar, edited by G.E.M. Jared
ConferenceReports
195
(Cambridge) and T. V~rady (Budapest), will be published both in Cambridge and Budapest. Tam~s Varady (CAI) Computer and Automation Institute Hungarian Academy of Sciences Budapest Hungary
Flexible Manufacturing Systems The 1st International Conference on Flexible Manufacturing Systems, sponsored and organized by IFS Conferences Ltd., was held in Brighton, U.K. from October 20-22, 1982. Participating sponsors included the British Robot Association, the Department of Industry (U.K.), the Production of Engineering Research Association (U.K.), FMS Magazine (U.K.), the Institute for Production and Automation (IPA) (Stuttgart, West Germany) and the Computer and Automated Systems Association of the Society of Manufacturing Engineers (U.S.A.). We present below, a report on the lectures delivered at this conference.
Automation or Liquidation L. Wood (GEC Electrical Projects Ltd.) suggested that without flexible automation, liquidation will inevitably follow. The timing of such an unhappy event depends on the competition; whether this is to be in a national sense, by competition from low labor rates of developing countries manufacturing ordinary everyday goods, or in a company sense where direct competitors at home or abroad are using techniques to make their businesses slimmer and more competitive. Wood used the expression "flexible automation" in a business sense, i.e. a means of making money. An alternative title for his lecture is "The Application of Automation to a Flexible Manufacturing System will Prevent Liquidation". Principles of Flexibility According to J.A. Buzacott (University of Toronto, Canada), "flexibility" is the essential fea-
ture of flexible manufacturing systems. One measure of flexibility, job flexibility, relates to the mix of jobs which the system can process. In general, productivity tends to decline with increasing job flexibility. Another measure of flexibility, machine flexibility, relates to the effect on the system of internal disturbances such as breakdowns. Machine flexibility can, with appropriate design and operation of the system, increase with increasing job flexibility. This suggests that for maximum performance there is an optimum degree of job flexibility. Buzacott proposed a number of principles for ensuring that the performance of an FMS is maximized. Status in Japan In Japan, efforts have been devoted to the embodiment of potentiality of flexible manufacturing systems to cope with the growing demand for the effective small batch production. Considering the increasing importance of the FMS, it is of great interest to study and overview the FMSs that are in practical use. T. OhmL Y. Yoshida (Mechanical Engineering Laboratory, Japan) and Y. Ito (Tokyo Institute of Technology, Japan) presented the results of a survey study on the FMS being implemented in Japan. By showing the statistical data on their dominant characteristics, they clarified the present status and trends. Developments in Japan An assessment of the developments of FMS in Japan was made by J.A.G. Knight (University of Nottingham, U.K.), based on information gained