Cam mechanics is one of the most popular devices for generating irregular motions and is widely used in automatic equipment,such as textile machines,internal combustion engines,and other automatic devices.In order to ...Cam mechanics is one of the most popular devices for generating irregular motions and is widely used in automatic equipment,such as textile machines,internal combustion engines,and other automatic devices.In order to obtain a positive motion from the follower using a rotating cam,its shape should be correctly designed and manufactured.The development of an adequate CAD/CAM system for a cam profile CNC grinding machine is necessary to manufacture high-precision cams.The purpose of this study is the development of a CAD/CAM system and profile measuring device for a CNC grinding machine to obtain an optimal grinding speed with a constant surface roughness.Three types of disk cams were manufactured using the proposed algorithm and procedures to verify effectiveness of the developed CAD/CAM system.展开更多
The formed principle and CNC grinding machining method of isometric polygonal profile are studied deeply and systematically. Equation about section curve of isometric polygon profile is set up by means of geometric pr...The formed principle and CNC grinding machining method of isometric polygonal profile are studied deeply and systematically. Equation about section curve of isometric polygon profile is set up by means of geometric principle. With the use of differential geometry theory, the curve is proved to be with geometric feature of convex curve. It is referred to as Isometric Polygonal Curve (IPC), because that is a kind of convex curve on which the distance between any parallel tangent lines is equal. Isometric Polygonal Profile (IPP) or Isometric Polygonal Cone Profile (IPCP) or Isometric Polygonal Topless Cone (IPTC) is formed with the IPC and straight line as generating curve. But the machining and measuring of the IPCP are so inconvenient that it has little value. Keeping in mind the characteristic of the IPP and IPTC, this paper puts forward the program method of CNC grinding machining. Isometric polygonal profile connection is a kind of polygonal profile connection. It has the superiority over keys (prismatic key & spline etc), and can be suit for the situations such as high rotative velocity, large torque, high precision, and small fixed room and vibration. Nowadays, some countries such as America, Russia, German and Switzerland applied CNC machining to the machining of polygon surface coupling parts, which makes their applications in machine productions such as motor engine, heavy machine increase day by day. But reports about concrete machining technology of isometric polygonal profile and programming of CNC machining program are very few. CNC grinding of the IPP and IPTC is one kind of the precision machining technology. It is of great importance to the popularization of the IPP and IPTC connection. From the forming mechanism, we can see that the machining and measuring of the IPP and IPTC are convenient, and therefore they have the value of the popularization. But the machining and measuring of the IPCP are so inconvenient that it has little value. In the programming the CNC grinding of the IPP and IPTC, it is more reasonable to calculate the coordinate of node according to the approaching method of equal error arc. According to the method of CNC grinding mentioned above to design the grinding machine, the structure is simple and of economical and practical.展开更多
The thermal induced errors can account for as much as 70% of the dimensional errors on a workpiece. Accurate modeling of errors is an essential part of error compensation. Base on analyzing the existing approaches of ...The thermal induced errors can account for as much as 70% of the dimensional errors on a workpiece. Accurate modeling of errors is an essential part of error compensation. Base on analyzing the existing approaches of the thermal error modeling for machine tools, a new approach of regression orthogonal design is proposed, which combines the statistic theory with machine structures, surrounding condition, engineering judgements, and experience in modeling. A whole computation and analysis procedure is given. Therefore, the model got from this method are more robust and practical than those got from the present method that depends on the modeling data completely. At last more than 100 applications of CNC turning center with only one thermal error model are given. The cutting diameter variation reduces from more than 35 μm to about 12 μm with the orthogonal regression modeling and compensation of thermal error.展开更多
Cylindrical Cam Mechanism which is one of the best eq uipments to accomplish an accurate motion transmission is widely used in the fie lds of industries, such as machine tool exchangers, textile machinery and automa t...Cylindrical Cam Mechanism which is one of the best eq uipments to accomplish an accurate motion transmission is widely used in the fie lds of industries, such as machine tool exchangers, textile machinery and automa tic transfer equipments. This paper proposes a new approach for the shape design and manufacturing of the cylindrical cam. The design approach uses the relative velocity concept and the manufacturing approach uses the inverse kinematics concept. For the shape desig n, the contact points between the cam and the follower roller are calculated bas ed on relative velocity of which the direction is on the common tangential line, and then the whole shape of cam is determined from transformation of the coordi nate system. For the manufacturing procedures, the location and the orientation of cutter path can be allocated corresponding to the designed shape data. The in tegral NC code for multi-axis CNC machining center is created using the inverse kinematics concept from the data of the location and the orientation of cutter path. As the advantages of the proposed approach, the machine tool is designed t o having an alternative size in fabricating the general cam, while the tool must be fitted to diameter size of the follower in the conventional approach. Finally, CAD/CAM program, "Cylindrical DAM", is developed on C++ lan guage. This program can perform shape design, manufacturing and kinematics simul ation, which can make integral NC code for multi-axis CNC machining center. The proposed method can be applied easily on fields of industries.展开更多
基金Project(RTI04-01-03) supported by the Regional Technology Innovation Program of Ministry of Knowledge Economy (MKE),Korea
文摘Cam mechanics is one of the most popular devices for generating irregular motions and is widely used in automatic equipment,such as textile machines,internal combustion engines,and other automatic devices.In order to obtain a positive motion from the follower using a rotating cam,its shape should be correctly designed and manufactured.The development of an adequate CAD/CAM system for a cam profile CNC grinding machine is necessary to manufacture high-precision cams.The purpose of this study is the development of a CAD/CAM system and profile measuring device for a CNC grinding machine to obtain an optimal grinding speed with a constant surface roughness.Three types of disk cams were manufactured using the proposed algorithm and procedures to verify effectiveness of the developed CAD/CAM system.
文摘The formed principle and CNC grinding machining method of isometric polygonal profile are studied deeply and systematically. Equation about section curve of isometric polygon profile is set up by means of geometric principle. With the use of differential geometry theory, the curve is proved to be with geometric feature of convex curve. It is referred to as Isometric Polygonal Curve (IPC), because that is a kind of convex curve on which the distance between any parallel tangent lines is equal. Isometric Polygonal Profile (IPP) or Isometric Polygonal Cone Profile (IPCP) or Isometric Polygonal Topless Cone (IPTC) is formed with the IPC and straight line as generating curve. But the machining and measuring of the IPCP are so inconvenient that it has little value. Keeping in mind the characteristic of the IPP and IPTC, this paper puts forward the program method of CNC grinding machining. Isometric polygonal profile connection is a kind of polygonal profile connection. It has the superiority over keys (prismatic key & spline etc), and can be suit for the situations such as high rotative velocity, large torque, high precision, and small fixed room and vibration. Nowadays, some countries such as America, Russia, German and Switzerland applied CNC machining to the machining of polygon surface coupling parts, which makes their applications in machine productions such as motor engine, heavy machine increase day by day. But reports about concrete machining technology of isometric polygonal profile and programming of CNC machining program are very few. CNC grinding of the IPP and IPTC is one kind of the precision machining technology. It is of great importance to the popularization of the IPP and IPTC connection. From the forming mechanism, we can see that the machining and measuring of the IPP and IPTC are convenient, and therefore they have the value of the popularization. But the machining and measuring of the IPCP are so inconvenient that it has little value. In the programming the CNC grinding of the IPP and IPTC, it is more reasonable to calculate the coordinate of node according to the approaching method of equal error arc. According to the method of CNC grinding mentioned above to design the grinding machine, the structure is simple and of economical and practical.
文摘The thermal induced errors can account for as much as 70% of the dimensional errors on a workpiece. Accurate modeling of errors is an essential part of error compensation. Base on analyzing the existing approaches of the thermal error modeling for machine tools, a new approach of regression orthogonal design is proposed, which combines the statistic theory with machine structures, surrounding condition, engineering judgements, and experience in modeling. A whole computation and analysis procedure is given. Therefore, the model got from this method are more robust and practical than those got from the present method that depends on the modeling data completely. At last more than 100 applications of CNC turning center with only one thermal error model are given. The cutting diameter variation reduces from more than 35 μm to about 12 μm with the orthogonal regression modeling and compensation of thermal error.
文摘Cylindrical Cam Mechanism which is one of the best eq uipments to accomplish an accurate motion transmission is widely used in the fie lds of industries, such as machine tool exchangers, textile machinery and automa tic transfer equipments. This paper proposes a new approach for the shape design and manufacturing of the cylindrical cam. The design approach uses the relative velocity concept and the manufacturing approach uses the inverse kinematics concept. For the shape desig n, the contact points between the cam and the follower roller are calculated bas ed on relative velocity of which the direction is on the common tangential line, and then the whole shape of cam is determined from transformation of the coordi nate system. For the manufacturing procedures, the location and the orientation of cutter path can be allocated corresponding to the designed shape data. The in tegral NC code for multi-axis CNC machining center is created using the inverse kinematics concept from the data of the location and the orientation of cutter path. As the advantages of the proposed approach, the machine tool is designed t o having an alternative size in fabricating the general cam, while the tool must be fitted to diameter size of the follower in the conventional approach. Finally, CAD/CAM program, "Cylindrical DAM", is developed on C++ lan guage. This program can perform shape design, manufacturing and kinematics simul ation, which can make integral NC code for multi-axis CNC machining center. The proposed method can be applied easily on fields of industries.
