Papers by Keyword: Hard-Brittle Materials

Abstract: Texturing processing experiment of SiC and YG8 surface was done by using lamp-pumped YAG-T50 laser marking machine and the depth of groove and the surface roughness was measured by using PS50 measurement which is non-contact. Through experiment, process parameters, such as effective vector step, effective vector step delay, Q frequency, laser current, effecting on the quality of the micro-shape processing were been researched. The experimental results show that, when effective vector step delay or laser current increases, the depth of the helical groove increases;while effective vector step or the Q frequency increases, the depth decreases;the surface roughness value decreases along with increasing of effective vector step delay Q frequency and laser current, increasing when effective vector step increases.

Abstract: Rotary ultrasonic machining (RUM) is widely used for machining virous kinds of hard-brittle materials. This article aims to study ultrasonic machining surface quality of zirconia ceramic, low-carbonsteel boltwith self-developed rotary ultrasonic machine. The surface roughness could be detected and observed by Taylor Hobson surface roughness instrument and Keyence microscope.The experimental resultsshow that the surface quality achieved by rotary ultrasonic machining is better than bytraditional mechanical machining. Rotary ultrasonic machininghas advantages for machining hard-brittle materials.

Abstract: t is known that cutting force is the key to reasonably select cutting parameters, and the base to study the cutting mechanism. Genetic Algorithm and multiple regression analysis were adopted to achieve cutting force predicted model of multi-diamonds fast milling hard-brittle materials with defined diamond grains pattern by single diamond fast milling hard-brittle materials experiments. Results show that cutting force predicted model by genetic algorithm has higher precision than that model by multiple regression, and the cutting force prediction method based on genetic algorithm is more suitable for those hard-brittle materials which components are relatively soft and simple. Predicted model can afford another study direction for processing analysis of diamond tools, tools making and processing parameters selection from the view of diamond grain practice cutting.

Abstract: Ultrasonic machining (USM) is an effective method for machining of hard brittle materials. In this process, the slurry is supplied to the gap between the workpiece and the ultrasonic vibrating tool, and the materials are removed by the impacts of the abrasive grains that are pressurized by an ultrasonic vibrating tool. The purpose of this research is to achieve precise and efficient microfabrication on hard brittle materials by USM. However, in the case of microfabrication, chipping which is generally observed around the edges of machined micro holes and grooves, deteriorates the machining accuracy. In addition, there is another problem in that the machining efficiency decreases with the progress of the machining. Electrorheological fluid-assisted USM has been proposed as a countermeasure to these problems. In the present study, the problems and countermeasures associated with the machining of high-aspect ratio micro holes in hard brittle materials by electrorheological fluid-assisted USM are investigated. By positioning an auxiliary electrode under the workpiece, it becomes possible to keep the electric field high even when the machining depth becomes large. As a result, high-precision and high-aspect ratio micro holes can be machined on hard brittle materials.

Abstract: Hard-brittle materials have been popular used in manufacture experience because of their excellent performances. However the low plasticity, frangibility and non-conduction make the machining very difficult, especially in ultra-precise surface fabrication. Therefore, ultrasonic vibration is introduced to conventional lapping for the purpose of proper lapping force, higher removal rate and fine surface quality. Through conventional and ultrasonic lapping experiment of hard-brittle materials with different lapping parameters and different vibration models, the empirical formula of lapping force in ultrasonic lapping is deduced by orthogonal regression analysis, the optimum lapping parameters are put forward and the primary and secondary influencing sequence of parameters on lapping force is presented. Moreover, the influencing rule of different lapping parameters such as rotational speed, feed speed, oilstone grit and lapping depth etc. on lapping force is carried out. Experimental results show that ultrasonic vibration lapping is a high efficient processing method adapting to hard-brittle materials.