Papers by Author: Hu Li

Abstract: Medical titanium plates with smooth surface will be long-standing in body under the condition of free state when it used for bone fixation. To solve this problem, function-surface titanium plates with a certain roughness and shape must be grinded. So ceramic CBN abrasion wheel is used to grind titanium alloy in CNC machining tool and the status of force, heat and vibration in the grinding process will be monitored in the same time. The surface morphology which can meet the growth of tissue could be obtained in a certain technological conditions by observing the grinded surface with super depth of field microscopy devices.

Abstract: Based on the response style of Custom/Server, the optimization model system of milling machining technique has been built up, in which the current network source, technology and the Rough Set theory was utilized. The purpose of the system is to get the maximum productivity under the conditions that the present face roughness Ra and dimension precision must be assured. The results shows that the Rough Set can be used to get the formula when the sample information is not of precision caused by the overlap of machining parameter class. The formula induced from Rough Set theory can be used to optimize the parameter of milling machining from the technique department distributed in different location by internet

Abstract: Design methods for medical rapid prototyping (RP) of personalized cranioplasty implants are presented in this paper. RP offers an easier way to design customized implants and manufacture them within a very short period. Computed tomography (CT) scans were acquired on a General Electric CT scanner and converted to solid models using Mimics software from Materialise. Stereo lithography patterns were prototyped using Objet build style on a Eden 250.The models helped the surgeons plan and rehearse the surgery well in advance. RP biomedical model is greatly convenient to diagnosis and treatment planning. It could decrease the operation time and the risk of misinterpretation of the medical problem. A physical biomedical model also facilitates surgery planning and makes the rehearsal and simulation of the operation possibly.

Abstract: The most frequent cause of defect in the mandible is tumor-related surgery. Larger defects cause severe morbidity due to disturbances in function and esthetics. A fibular free flap is one way of filling a bony hole in either the upper or lower jaw. It is one of the common ways of replacing bone that has been removed for cancer treatment. Doctors use a free fibular flap which is grafted from the patient who needs a transplant operation to fit the defect. In this study, a new method combining preoperative planning and rapid prototyping for mandibular fibula free flap reconstruction after tumor surgery was made based on Mimics software simulating surgery on a workstation. The preparatory work of surgery is divided into two parts: software simulation and model building. During software simulation the authors were able to choose the best site for the osteotomies regarding circulation and the model building can increase the precision and speed of treatment. A description of our surgical approach is presented and is supplemented by an illustrative case.

Abstract: In order to further improve machining quality of superhard materials, it was presented that adds a squeeze film damper on the wheel spindle of ultrahigh speed grinder as a assistant elastic sustain to attenuate the vibration of the wheel spindle. Work principle of squeeze film damper was analyzed; the squeeze film pressure distribution was researched through simulation and damper parameters effect on damping coefficient was studied. Base on the theory research the damper was designed and experiments was done. Experimental result shows the amplitude of the grinding wheel spindle can be reduced 20% and machining quality of superhard materials can be improved 10%～20%. Research works provides a new method for superhard materials machining.

Abstract: Under the conditions of the mode of production drifting towards extensive collaboration mode, the process capacity oriented to machining factory should be analyzed and estimated, which is the essential precondition for factory to decide whether to accept a piece of manufacturing order form. Based on the situation, with the production quality checking and analysis focused, a kind of process capacity analysis and estimation was brought forward for the collaborational machining factory under the mode of quality control. The model based on quality driven for the process capacity estimation was provided to solve the critical problem. And the network service system of process capacity estimation was established, by making full use of quality function analysis (QFD), similar procedure query and rough set theory combined with the character parameters such as work-part size tolerance, surface roughness, manufacturing time, cost and etc. Furthermore, some key enabling technologies were instigated in detail, including quality control technology oriented low volume customization and process capacity analysis technology based on rough set (RS) theory.

Abstract: The concept of agent and multi-agent was introduced. The agent structure, negotiation strategies, and the negotiation mechanism were also researched. Based multi-agent, an automated negotiation method for bilateral contracts is proposed, which can efficiently carry out multilateral negotiations with multi-attributes in distributed environments. This framework supports efficiently multilateral negotiation. In the end, the negotiation is conducted and demonstrated that multi-agent can improve negotiation efficiency by saving negotiation time and cost.

Abstract: For improving grinding quality of ultrahigh speed grinding a new design method for ultrahigh speed grinding spindle is put forwarded based on squeeze film damping technology. Working principle of squeeze film damper of ultrahigh speed grinding spindle is study and differential equations of motion of the ultrahigh speed grinding wheel spindle with a squeeze film damper are set up according to d'Alembert principle. Effects of design parameters of the damper on the motion section of the spindle are studied by the way of simulation based on it. Research works show that the dynamic characteristic of ultrahigh speed grinding spindle can be improved well through adding a squeeze film damper. Research works provides a new technology for the design of the ultrahigh speed grinding spindle system.

Abstract: Adopting the method of PIV, systematical theory analysis and experiment research were made on the airflow field distribution of super-high speed pectination grinding wheel, as well as experiment design and data acquisition, the data processing was carried out through the software of FlowMap, Tecplot, and Matlab. By analysis and discussion focused on experiment results, the general rules of airflow field distribution in super-high speed pectination grinding wheel were preliminary drawn, which provides the research foundation with a view to find a new method for the effective supply of super-high speed grinding coolant.

Abstract: Ultrahigh speed grinding is a kind of high efficient metal cutting method. In order to improve ability of ultrahigh greed grinding wheel spindle to resist vibration and grinding quality, an ultrahigh speed grinding spindle system with a squeeze film damper (SFD) was designed based on the theory of squeeze film damping technology. Pressure distribution and squeeze film stiffness characteristic of SFD was study by the method of simulation. Based on theory study an ultrahigh speed spindle system with a SFD was designed and experiments were done. The study results show that application of SFD technology can effectively restrain vibration which is caused by the imbalance quality when the grinding wheel spindle turning at ultrahigh speed. And the speed of the grinding spindle is higher and the effect of attenuation of SFD to grinding spindle is better. Research works provides a new technology for the design of the ultrahigh speed grinding spindle system.