A universal model for ruled surface's linear cutting with four-axis linkage machine
At present, the ruled surface's multi-axis manufacture is a hot research direction, but its universal mathematic model as key theory problem hasn't been established so far. To solve the problem of ruled surface's manufacture with four-axis linkage machine, we worked out the intersection line between the lateral surface and the horizontal plane of upper-lower guiding device through geometry method, and then established the universal mathematical model to manufacture the lateral surface of the work pieces under the condition that the lower guide is fixed. To verify the exactness of the model, we took the four-edge frustum and triangle-circle frustum as example. The model has universal use value in guiding practical manufacturing.
Performance prediction of TBM disc cutting on granitic rock by the linear cutting test
This paper aims to estimate the TBM disc cutter performance on Hwandeung Granite, one of the representative rock types in Korea by the Linear Cutting Machine. In the Linear Cutting test, the digital photogrammetric technique was newly adopted to measure three-dimensional cutting volumes and to apply them to the derivation of design parameters of TBM cutterhead. In this study, a series of linear cutting tests by a TBM disc cutter with the diameter of 17 inches were carried out by varying cutter spacing as well as cutter penetration conditions. From the tests, the optimum ratio of cutter spacing and penetration depth was derived for Hwandeung Granite. However, experimental results showed that three-dimensional cutting volumes measured by the photogrammetrical technique were not very close to those that were simply calculated from mechanical set-up values of each linear cutting test. Considering that the cutting procedure of a TBM disc cutter is not one-dimensional but three-dimensional failure mechanism, the use of three-dimensional cutting volumes as a performance parameter of a TBM disc cutter is indispensable to design a more accurate and reliable TBM cutterhead. (A) This paper was presented at Safety in the underground space - Proceedings of the ITA-AITES 2006 World Tunnel Congress and the 32nd ITA General Assembly, Seoul, Korea, 22-27 April 2006. For the covering abstract see ITRD E129148. "Reprinted with permission from Elsevier".
Identification of alignment errors in five-axis machining centers using telescoping ball bar
This paper deals with the identification of alignment errors in five-axis machining centers. There are thirteen alignment errors in each five-axis machining center. Three alignment errors in the three translational slideways are identified by circular tests using a Telescoping Ball Bar. In this paper, assuming the use of a Telescoping Ball Bar, identification methods for the other ten alignment errors in five-axis machining centers are proposed. The theoretical background for identification is given by a form-shaping theory. The validity of the proposed identification method of alignment errors is confirmed by experiment.