Large NC machine tools or NC machine tools with elastic parts such as reducers tend to have mechanical low frequency vibration. With high gain servo control, low frequency vibration appears as machining point vibration, and results in deterioration of machining surface. In this article, two anti-vibration control methods to suppress machining point vibration are proposed based on two-mass model; one is for semi-closed control and the other is for full-closed control. The basic idea of the proposed control laws is to regard the position reference from NC not as for motor but as for load of two-mass system. Experiments were done and it is shown that both proposed laws effectively suppress the load angular error by allowing motor angular error.

抄録全体を表示

The study deals with an automatic measurement system for thickness of free curved plates. The system consists of a laser thickness gauge composed of faced two laser displacement sensors and an industrial robot as workpiece positioning device to achieve appropriate measuring posture. The system measures the workpiece shape, and the thickness based on the acquired shape data. In this paper, each error factors of the system are verified, and thickness measurement error was estimated from the verified error factors. From the experimental result, it was confirmed that it is possible to measure the thickness within the estimated error.

抄録全体を表示

Initial tool setting errors that could be generated while setting a cutting tool deteriorates machining accuracy. However, it is difficult to prevent an occurrence of the tool setting errors due to the manual setting process, which may increase in accordance with the number of the control axes. These errors make it difficult to locate tool control points at the right position while machining. Therefore, this study aims at detecting and compensating the setting errors without depending on operator's skill. A novel setting errors compensation method is proposed based on form shaping theory by using a dummy work and an on-machine measurement device. It is expected that the tool setting errors are compensated with high accuracy and efficiency because of automatic detection of the actual tool control points. From the conducted experiments, it is found that the proposed method has a potential to compensate the tool setting errors accurately and to achieve high efficient multi-axis control ultraprecision machining.

抄録全体を表示

Single layer graphene (SLG) is a two-dimensional carbon atom crystalline film. Its extraordinary physical properties, such as high electrical conductivity and high mechanical strength, have enabled rapid development of graphene-based transistors. Atomic force microscopy is a common tool used to determine the surface topography at a nanometer level and is applied to mechanical groove formation of SLG in our research. Since, the traditional scratch machining method was not proving to be very suitable in this regard, in this study, nanometer-scale vibration machining was carried out with a diamond-coated probe as a machining tool, and SLG on a SiO2 substrate was used as the workpiece. We find that the vibration machining method has higher machining precision than the traditional scratch machining method.
In addition, the vibration machining mechanism is also clearly discussed. By using the proposed vibration machining model focusing on energy, the precision of the machined groove can be predicted before machining. A qualitative comparison between theoretical value of proposed model and experiment value is provided.

抄録全体を表示