Development and application of expert system for d

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Development and application of hob design and manufacturing expert system

Abstract: applying the basic principle of spatial meshing, the general formulas for calculating the blade shape and shovel grinding profile of hob are established; Using cad/cam technology and expert system technology, a practical expert system for hob design and manufacturing is developed The paper also introduces the characteristics and application methods of hob design and manufacturing expert system

key words: hob; Expert system; Computer aided design/computer aided manufacturing

classification number: th 11 document identification code: a

article number: X (2000)

development and application of an expert system for the design and manufacture of hob cutters

shao Ming Tang Chao Jun Jin Jun Han Zhi Peng

(Dept. of Mechatronic Engineering, South China Univ. of Tech., Guangzhou 510640, China)

Abstract: a general formula that includes the calculation of the profile of hob tool and relief grinding wheel drives the lead screw pair to load after deceleration. Maybe such a situation can be considered as improved by applying the principle of spatial meshing A useful expert system for the design and manufacture of gear cutting hobbing is developed by making use of the cad/cam4 The characteristic and application of this system have been introduced since the acquisition of the automotive business department of Fischer composite technology company (ried im innkreis, Austria) and the establishment of the second composite parts factory near ort im innkreis, Austria in 2012

Key words: hob; expert system; The wide application of cad/cam ▲

computer technology in the mechanical industry has triggered a great change in the traditional way of mechanical design and manufacturing In the field of gear manufacturing, the emergence of some new methods of hob design and manufacturing and the productization of computer numerical control (CNC) high-speed gear hobbing machine have raised the gear hobbing technology to a new level and put forward higher requirements for the design and manufacturing of gear hobbing tools At present, the traditional approximate calculation method and the technology of dressing shovel grinding wheel with mechanical grinding wheel dresser commonly used in production cannot meet the needs of the technological progress of hob design and manufacturing On the other hand, with the deepening of the reform of the teaching system in Colleges and universities, more and more engineering and technical personnel in China understand computers, and the number of personnel who master the design and manufacturing technology of complex cutting tools in detail will gradually decrease Using expert system technology to develop practical expert system for gear hob design and manufacturing has become an important way to develop gear hob design and manufacturing technology

on the basis of deriving the general calculation formula of gear hob blade shape and shovel grinding contour shape, combining the experience and knowledge of experts in this field, and organically combining symbolic reasoning and numerical calculation, a practical hob design and manufacturing expert system (hdmes) is developed The system uses C language to compile the calculation program, uses AutoCAD to draw and output automatically, and uses VP_ Expert builds expert system knowledge base and realizes consultation and interpretation function, and develops friendly system integration interface with VB

In order to reduce the workload of expert system development and increase the versatility of the system, the author successfully derived the general formula for calculating the blade shape of hob and the contour shape of shovel sanding For the workpiece with any tooth shape, as long as a complete tooth shape is discretized into a list curve, the hob blade shape can be calculated by using the general formula for calculating the hob blade shape, and then the relief grinding contour can be calculated according to the hob blade shape Then, the system draws the blade shape of the hob and the outline shape of the shovel grinding sand on the screen (as shown in Figure 1), and stores the outline shape of the shovel grinding sand in a certain format in the database for FGS_ The 30n CNC forming gear grinder automatically generates the dressing software of the relief grinding wheel, and the relief grinding hob is grinded after the grinding wheel is trimmed

Fig. 1 profile of hob tool and relief grinding wheel

Fig.1 profiles of hob tool and relief grinding wheel

the general formula for the calculation of hob edge shape is derived by combining the space medium rack method and the tooth profile normal method. As long as the coordinate value of the workpiece tooth shape point represented by discrete values and the unit tangent vector of the point are provided, the axial edge shape of the hob can be calculated by using the general formula, For the standard straight groove zero rake hob, it is the blade shape of its rake face The calculation example shows that the calculation accuracy of this general formula is up to 0.1 μ m. It can completely meet the engineering requirements of hob design and manufacturing [1]

at present, tool designers usually only design hobs and do not consider the manufacturing problem of hobs. For gear hobs with arbitrary tooth shape, the calculation of relief grinding contour is very important. The development of gear hob design and manufacturing expert system cannot help solve the calculation problem of relief grinding contour In this study, the author deduces the general formula for calculating the relief grinding contour of hob, and calculates the relief grinding contour directly according to the hob blade shape calculated by the system When deriving the general formula of calculation, the CNC form relief grinding method is used to relief grind the hob. The calculated wheel profile data can be directly used in the automatic programming of CNC form gear grinding machine, so as to realize the integration of gear hob cad/cam This technology, which was jointly studied by Professor Akira Ishibashi of Kumamoto University of technology, Professor eihiro Yoshino of Saga University and the author of this paper, has been applied in gear tool manufacturers in Japan [2]

2 implementation of automatic drawing and database processing

after the design and calculation of the axial blade shape and structural size of the hob, the data required for automatic drawing has been stored in the database and data file The drawing program section reads out the required data from the database and data file, and generates the screen command integrated drawing file for AutoCAD system after appropriate conversion This drawing file is actually a text file, which collects all screen commands for drawing hob working diagram with AutoCAD system, and has been reasonably

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