Development of Table-on-Table-Type Five-Axis Machining Center: New Structure and Basic Characteristics

2011 ◽  
Vol 5 (2) ◽  
pp. 247-254 ◽  
Author(s):  
Naoshi Takayama ◽  
◽  
Hidehito Ota ◽  
Kensuke Ueda ◽  
Yoshimi Takeuchi ◽  
...  
Keyword(s):  
High Speed ◽  
Adjustment Process ◽  
Direct Drive ◽  
Rotary Axis ◽  
Advantages And Disadvantages ◽  
Machining Center ◽  
Wide Range ◽  
Drive Motor ◽  
Basic Characteristics ◽  
Five Axis

The demand for five-axis machining centers has been increasing rapidly, as companies seek “intensive processes” and “high accuracy.” However, it is generally more difficult for five-axis machining centers to achieve the same or higher accuracy than three-axis machining centers since it is necessary to have two more rotary feed axes besides the three linear feed ones. Many kinds of five-axis machining centers with various structures have been developed to date; an analysis of the advantages and disadvantages of major five-axis machining center structures was done first. As a result of this analysis, this paper focuses on the “table-on-table type” five-axis machining center. It is capable of accuracy because of its wide range of rotation for the rotary axis and its advantages in the adjustment process of the axis. and this paper proposes a five-axis machining center which has this construction. Furthermore, a new high-speed, highaccuracy, “table-on-table type” of five-axis machining center which uses a direct-drive motor for the rotary axis and a driven center of gravity for the linear axis has been developed based on this concept, and its accuracy has been verified.

Dynamic Hybrid Modeling of the Vertical Z Axis in a High-Speed Machining Center: Towards Virtual Machining

2007 ◽  
Vol 129 (4) ◽  
pp. 780-788 ◽  
Author(s):  
Giovanni Tani ◽  
Raffaele Bedini ◽  
Alessandro Fortunato ◽  
Claudio Mantega
Keyword(s):  
High Speed ◽  
Experimental Tests ◽  
Pneumatic System ◽  
Mechanical Structure ◽  
Virtual Machining ◽  
Feed Drive ◽  
Machining Center ◽  
Dynamic Hybrid ◽  
Five Axis ◽  
Machine Head

This paper describes the modeling and simulation of the Z axis of a five axis machining center for high-speed milling. The axis consists of a mechanical structure: machine head and electro-mandrel, a CNC system interfaced with the feed drive, and a pneumatic system to compensate for the weight of the vertical machine head. These subsystems were studied and modeled by means of: (1) finite element method modeling of the mechanical structure; (2) a concentrated parameter model of the kinematics of the axis; (3) a set of algebraic and logical relations to represent the loop CNC-Z feed drive; (4) an equation set to represent the functioning of the pneumatic system; and (5) a specific analytical model of the friction phenomena occurring between sliding and rotating mechanical components. These modeled subsystems were integrated to represent the dynamic behavior of the entire Z axis. The model was translated in a computer simulation package and the validation of the model was made possible by comparing the outputs of simulation runs with the records of experimental tests on the machining center. The firm which promoted and financed the research now has a virtual tool to design improved machine-tool versions with respect to present models, designed by traditional tools.

scholarly journals CRYPTOCURRENCY – DEFİNİTİON, FUNCTİONS, ADVANTAGES AND RİSKS

2021 ◽  
pp. 5-10
Author(s):  
Маріана Стойка
Keyword(s):  
High Speed ◽  
Legal Status ◽  
Maximum Speed ◽  
Virtual Currency ◽  
Customer Base ◽  
Advantages And Disadvantages ◽  
History Of ◽  
Investment Function ◽  
Degree Of Acceptance ◽  
Basic Characteristics

The emergence of “virtual currencies” is extremely recent, with a history of only 13 years. Being an ultra-new economic tool, it arouses interest and effervescent reactions, especially in terms of definition, but also about the cumulative effects it has begun to produce in the economic world. The subject also becomes controversial due to the fact that, being an economic instrument of absolute novelty, it is reflected in the legislation of very few countries in the world. One of the definitions determines as virtual currency – the digital representation of the value that is not issued or guaranteed by a central bank or a public authority, which is not necessarily linked to a legal currency and which does not have the legal status of the currency, but which can be accepted by natural or legal persons as a means of exchange and which may be transferred, stored and traded by electronic means. The evaluation of cryptocurrency publications has shown that most of them are related to attempts to establish legislative agricultural work for the operation of virtual currencies. The functions of the cryptocurrencies that we have defined are: the exchange and payment function, the hoarding function, the investment function and the attraction of funds necessary for the activity. Thus, we established that virtual currencies, as well as fiduciary ones, have the role of: means of payment, means of accumulation, means of capitalization and investments. Likewise, through this research we managed to highlight the main features and peculiarities of cryptocurrencies. Among the basic characteristics of cryptocurrencies we highlight: the high degree of security, maximum speed of transactions, full freedom from financial organizations, irreversibility of operations, full anonymity of transactions, open source, they can be ”mined”. Another approach was to determine the advantages and disadvantages and risks of using cryptocurrencies. The main advantages of using cryptocurrencies are related to its functions an caracteristics, such as: it represents a real alternative to classic banking services, market freedom, privacy of transactions, high speed of trnasactions, alternative payment methos, increasing the customer base etc. On the other hand there are some disatvantages. They are related mosly with the following risks: legal uncertainty, market volatility, low degree of acceptance, unsecured crypto wallets, risks related to use for illegal or criminal purposes, money laundering risks. Taking in consideration the global trend of the digitization of the society, the share and importance of fiat currencies will tend to decrease for the benefit of virtual currencies. Cryptocurrencies are becoming a real alternative to physical currencies, but its main disadvantage is that the public autorities are missing controlling it yet. Even so, in the nearest future the money could become digital figures.

Dynamic Hybrid Modeling of the Vertical Z Axis in an HSM Machining Center: Towards Virtual Machining

2005 ◽  
Author(s):  
Giovanni Tani ◽  
Raffaele Bedini ◽  
Alessandro Fortunato ◽  
Claudio Mantega
Keyword(s):  
High Speed ◽  
Dynamical Behavior ◽  
Experimental Tests ◽  
Pneumatic System ◽  
Fem Modeling ◽  
Mechanical Structure ◽  
Machining Center ◽  
Feed Drives ◽  
Five Axis ◽  
Machine Head

The paper describes the dynamical real-time simulation of the Z axis of a five axis machining center for high speed milling. The axis consists of a mechanical structure: machine head and electro-mandrel, a CNC Control System provided with feed drives and a Pneumatic System to compensate the weight of the entire vertical machine head. These three sub-systems have been studied and modeled by means of: • FEM modeling of the mechanical structure; • an equation set to represent the main functions of the CNC; • an equation set to represent the functioning of the Pneumatic System. These different modeling sub-systems have been integrated to obtain the entire actual dynamical behavior of the Z axis. A particular analysis was developed to represent the friction phenomena by a specific analytical model. Experimental activity was developed to test and validate the different modeling sub-systems, and other experimental tests were performed on the machining center to compare simulation outputs with experimental responses.

Development of High-Speed, High-Precision 5-Axis Integrated Machine Tools

2007 ◽  
Vol 1 (2) ◽  
pp. 103-107 ◽  
Author(s):  
Masahiko Mori ◽  
◽  
Hidehito Ota ◽  
Makoto Fujishima
Keyword(s):  
High Precision ◽  
Machine Tools ◽  
High Speed ◽  
Direct Drive ◽  
Machining Performance ◽  
Rotary Axis ◽  
Rotary Actuator

This paper describes the development of high-speed, high-precision 5-axis machine tools which can be used for both milling and turning. Conventional 5-axis machine tools are generally difficult to operate because the visibility is poor. Moreover, their precision is inadequate and the rotary axis speed is insufficient for turning. To deal with these factors, we developed a simple, high-precision 2-axis rotary actuator with high-speed direct drive motors. We studied the machining performance of 5-axis machining centers equipped with such direct drive motors.

Motion Control of Ultra-High-Speed Manipulator with a Flexible Link Based on Dynamically Coupled Driving

2006 ◽  
Vol 18 (5) ◽  
pp. 598-607 ◽  
Author(s):  
Tomoari Maruyama ◽  
◽  
Chunquan Xu ◽  
Aiguo Ming ◽  
Makoto Shimojo
Keyword(s):  
Motion Control ◽  
High Speed ◽  
Wrist Joint ◽  
High Accuracy ◽  
Human Motion ◽  
Golf Club ◽  
Direct Drive ◽  
Flexible Link ◽  
Ultra High Speed ◽  
Drive Motor

We have developed a golf robot whose swing simulates human motion. The design concept is to realize ultra-high-speed dynamic manipulation using a dexterous mechanism. The robot consists of a shoulder joint with a high-power direct-drive motor and a wrist joint with a low-power direct-drive motor. High-speed golf swings are realized by a sort of motion control, called dynamically-coupled driving which compensates for the lack of drive in the wrist joint. In this paper a new model accounting for golf club flexibility with all parameters identified in experiments was developed. Based on this, we generated and implemented trajectories for different criteria. Experimental results confirmed the high accuracy of motion control and the feasibility of golf club flexibility in ultra-high-speed manipulation.

Motion Tuning Method of Linear Axes and Rotary Axis Under a Constant Cutting Speed Vector at End-Milling Point With a Five-Axis Controlled Machining Center

2015 ◽  
Author(s):  
Takamaru Suzuki ◽  
Takakazu Ikegami ◽  
Takayuki Akai ◽  
Toshiki Hirogaki ◽  
Eiichi Aoyama ◽  
...  
Keyword(s):  
Surface Quality ◽  
End Milling ◽  
High Surface ◽  
Cutting Speed ◽  
Surface Shape ◽  
Feed Speed ◽  
Shape Error ◽  
Rotary Axis ◽  
Machining Center ◽  
Five Axis

Recently It is difficult to maintain the high surface quality ingenerating curved surface shape under five-axis controlled end-milling. In this study, we aimed at maintaining feed speed vector at milling point by controlling two linear axes and a rotary axis with a five-axis machining center, to improve machined surface quality and suggested a method for solving shape error of machined workpiece considering differences of three axes’s sarvo characteristics. As the results, it could be seen that shape error greatly decreased based on the proposed method.

scholarly journals AdjustSense: Adaptive 3D Sensing System with Adjustable Spatio-Temporal Resolution and Measurement Range Using High-Speed Omnidirectional Camera and Direct Drive Motor

Sensors ◽  
2021 ◽  
Vol 21 (21) ◽  
pp. 6975
Author(s):  
Mikihiro Ikura ◽  
Sarthak Pathak ◽  
Jun Younes Louhi Kasahara ◽  
Atsushi Yamashita ◽  
Hajime Asama
Keyword(s):  
Temporal Resolution ◽  
High Speed ◽  
Measurement Range ◽  
Direct Drive ◽  
Multiple Measurement ◽  
Sensing System ◽  
Drive Motor ◽  
3D Sensing ◽  
Spatio Temporal ◽  
Conventional Systems

Many types of 3D sensing devices are commercially available and were utilized in various technical fields. In most conventional systems with a 3D sensing device, the spatio-temporal resolution and the measurement range are constant during operation. Consequently, it is necessary to select an appropriate sensing system according to the measurement task. Moreover, such conventional systems have difficulties dealing with several measurement targets simultaneously due to the aforementioned constants. This issue can hardly be solved by integrating several individual sensing systems into one. Here, we propose a single 3D sensing system that adaptively adjusts the spatio-temporal resolution and the measurement range to switch between multiple measurement tasks. We named the proposed adaptive 3D sensing system “AdjustSense.” In AdjustSense, as a means for the adaptive adjustment of the spatio-temporal resolution and measurement range, we aimed to achieve low-latency visual feedback for the adjustment by integrating not only a high-speed camera, which is a high-speed sensor, but also a direct drive motor, which is a high-speed actuator. This low-latency visual feedback can enable a large range of 3D sensing tasks simultaneously. We demonstrated the behavior of AdjustSense when the positions of the measured targets in the surroundings were changed. Furthermore, we quantitatively evaluated the spatio-temporal resolution and measurement range from the 3D points obtained. Through two experiments, we showed that AdjustSense could realize multiple measurement tasks: 360∘ 3D sensing, 3D sensing at a high spatial resolution around multiple targets, and local 3D sensing at a high spatio-temporal resolution around a single object.

Development of Sensor-Less Power-Assisted System with Disturbance Observer Considering High Friction

2013 ◽  
Vol 25 (6) ◽  
pp. 1020-1028
Author(s):  
Takanori Miyoshi ◽  
◽  
Ryosuke Imai ◽  
Kazuhiko Terashima ◽  
Kanemitsu Ochiai ◽  
...  
Keyword(s):  
High Power ◽  
Disturbance Observer ◽  
High Speed ◽  
Static Friction ◽  
Force Sensor ◽  
Direct Drive ◽  
Speed Reduction ◽  
Drive Motor ◽  
Support Device ◽  
Friction Parameters

Japan has a dwindling birthrate and a rapidly aging population, which has led to an increasing number of elderly laborers. Although this has spurred development into power-assisted (PA) equipment that can reduce the physical demands, most of power assisted systems developed so far have used the force sensor, a direct drive motor, or a high power motor. The PA machine using force sensor is unable to detect and avoid obstacles that might collide with nonsensor components of the machine. The direct drive motor is too expensive for the practical use and its power tends to increase. According to Japanese law, a high power motor is not allowed to cooperate together with laborers in the factory. Thus, in this research, a sensor-less power-assisted (PA) system capable of estimating operator force based on a disturbance observer and friction correction is designed and built for a high friction production support device using a lowcapacity servo motor and a high-speed reduction ratio reducer. First, a dynamic model of a production support device is identified with specific friction parameters. Next, a sensor-less PA system is constructed that is equipped with an appropriate disturbance observer and dynamic friction correction. Moreover, the static friction issues are solved by the regular driving command. Finally, the accuracies of estimated force are examined, and the effectiveness of the constructed sensor-less PA system is verified.

Research on the Post-Processing Algorithm about Five-Axis High-Speed Machine Center

2011 ◽  
Vol 141 ◽  
pp. 460-464
Author(s):  
Wei Zhao ◽  
Tedros Alem Hadush ◽  
Qiong Yi He
Keyword(s):  
Control System ◽  
High Speed ◽  
Numerical Control ◽  
Processing Algorithm ◽  
Numerical Control System ◽  
Post Processing ◽  
Machine Center ◽  
Machining Center ◽  
Five Axis ◽  
High Speed Machine

Research on the post-processing algorithm with the DMC75VLinear 5-axis machining center and Heidenhain iTNC530 numerical control system. The formulae about angles B and C are proposed combined with the instruction of M128.The NC codes gotten from this method had been proved in the DMC75VLinea machine, so the post-processing algorithm is tested correctly and reliably.

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