Papers by Author: Xiao Hong Lu

Abstract: Because of the differences in spindle speed and extended length of micro milling cutter, Tool life and machining surface quality vary markedly. Therefore, a geometric model of carbide end mill whose diameter is 0.2mm is built. With free meshing method, meshing density is set up reasonably, which ensure the rationality of the built finite element model. On the premise of considering the extended length of the micro milling cutter, apply linear load on the main cutting edge and front-cutting edge, carry out the deformation and stress analysis using finite element software. Applying different spindle speeds under four extended lengths, through comparing maximum stress and strain under four extended lengths, change rules are summarized and the extended lengths of the tool suited for micro-milling are achieved.

Abstract: Double loop cutters arrangement can settle the contradiction between rotational inertia of the tool magazine and the dimension limitation of the cutter head effectively, and increase the store of tools. Disc type tool magazine with double loop cutters arrangement is designed and researched. The spring steel 65Mn is used to manufacture elastic cutter fixture as the holding device for its inner and outer loop tools. The dynamic deformation of elastic cutter fixture is discussed. The entire geometric movement process of elastic cutter fixture from being opened by the tool holder to accomplishing the whole action is analyzed. The effect and trend of inner stress caused by geometric deformation are studied. Furthermore, the force condition in each part of tool fixture can be calculated, thus predicting the motion stability and reliability of the elastic cutter fixture, and providing theory references for the design of elastic cutter fixture.

Abstract: The indexing precision of power tool rest cutter head is the prima choice to judge the performance of the tool rest and the test of it is the premise of the tool rest quality. Considering the lack of an effective indexing precision detection method of power tool rest cutter head, the testing methods of the indexing precision of power tool rest cutter head are discussed and an indexing precision testing system based on photoelectric auto collimator is set up. The testing results can show the indexing error of every tool. The studied system of the indexing precision of power tool rest cutter head is suitable for various indexing device to realize dynamic indexing accuracy testing and the system has a high reliability and testing accuracy.

Abstract: The scarcity and imperfection of power tool rest noise detection method have seriously limited the development of the industry of CNC lathe, lathe and milling composite machining center. A noise detection system based on LabVIEW is developed. The developed system adopts a noise sensor as noise detection component to test the noise information of the power tool rest. To enhance the anti-interference ability of this system, the sampled signals are amplified and adjusted by the signal disposal instrument. Through the spectrum transformation and spectrum analysis of the sampled noise signals, the noise causes of the power tool rest can be inquired and the concerned measurements can be taken to reduce the noise effectively. Finally, the sampled data is stored by the data saving function.

Abstract: Tool magazine and automatic tool changer is important parts to fulfill the machining center tool reserve and automatic changing of the spindle tool. The reliability of them directly affects the performance of the host. But recently there are no researches on the reliability evaluation methods, so considering this situation, the reliability evaluation researches on CNC machine tools and their main parts at home and abroad are analyzed and concluded. Combining the collected failure data of the circular tool magazine and automatic tool changer, use MTBF (Mean Time between Failures), MTTR (Mean Time To Repair) and the inherent availability index to realize the reliability evaluation of the circular tool magazine and automatic tool changer. Thus put forward a method to study the reliability evaluation of circular tool magazine and automatic tool changer.

Abstract: As the tool magazine and automatic tool changer (ATC) are the important function units to reserve and change tools for the machining center, the tool-changing rate affects their reliability life which directly influences the performance level of the machining center. However, the reliability of the tool magazine and ATC has not yet got a reasonable evaluation index. Directing at the features of the tool magazine and ATC system, the mean tool change numbers between failures evaluation index is proposed, which is used to calculate the mean time to repair and estimate the collected failure data of the chain-type tool magazine and ATC. It can be seen that the tool magazine with continuous tool-changing adopts the mean tool change numbers between failures as the reliability evaluation index.

Abstract: The realization of the handwheel function is a key problem for development of numerical control system of micro milling machine. This paper introduced the interface specifications and hardware connecting methods of handwheel NK100AB2, developed control program based on PMAC (Programmable Multi-Axis Controller) and industrial personal computer, finally achieved the function of axes selecting and the feed rate selecting. Based on the traditional edge detector tool setting method, an improved tool setting method is proposed. The inverted micro milling cutter hilt is used to replace the traditional edge detector, which avoids the opposite reamer error caused by the irregular cutter blade shape, finally, tool setting function is achieved through the collecting of electrical signal. The research will provide a useful reference for the realization of handwheel and tool setting of micro milling machine based on PMAC.