Advanced Materials Research Vol. 797

Abstract: The purpose of this study was to achieve grooving on glass substrates with high levels of efficiency and precision with the use of a diamond grindstone with a small diameter in the range of 1.0-1.8 mm. Mechanical material removal by grinding has high efficiency and enables process control for creating complicated forms, but has a drawback of generating chippings on the processed surface of the brittle glass material. The study gave ultrasonic vibration of 10 μm at 20 kHz in the thrust direction to the rotating small-diameter diamond grindstone in the grinding process, in order to attain high levels of efficiency and precision in micro-grooving of glass. The grooving approach with ultrasonic vibration did create some minor chippings, but succeeded in meeting the target of reducing the average size of chippings around the groove to 0.1 mm or less.

Abstract: In order to cope with high demanded industry requirements. The super-hard alloys such as Tungsten Carbide have been widely used in aerospace and defense industries. So far, the grinding operation is still the most popular machining process being used to cut these materials in shape. But, owing to the nature of these materials mechanical properties, always made it very difficult to grind as well as to cut. Nevertheless, the allowable grinding parameters are resisted to very limited range and always require use very expensive super abrasive grinding wheel. Recently, study by many researchers show that the ultrasonic assist grinding had the advantage of higher material removal rate, less cutting force and lower cutting temperature. In the mean time, the tool life had been improved greatly. In this study, the conventional GC grinding wheel was used in the experiments to study the material removal rate; grinding force; surface roughness as well as specific grinding energy with and without the ultrasonic assist. The results show that these difficult-to-cut materials can be ground easier with proper ultrasonic assist and low-priced grinding wheel.

Abstract: In this paper, the ultra-precision mirror polishing technology was adopted for mirror processing experimental study of Aluminum Alloy mobile phone shell. The experiments show that: polishing pressure, Grinding disc speed, the texture and hardness of polishing pad and abrasive particle size are the main factors to affect the surface quality. Through to optimize these parameters matching combination, can effectively improve the surface quality and reduce the surface roughness and obtain surface roughness is Ra0.026μm.

Abstract: In order to reduce the cost, improve the surface of workpiece machined by AFM and make out reasonable technological parameters of AFM, AFM theory model has been developed in the present work. The process parameters such as pressure, piston velocity, temperature and viscosity impacting on the workpiece surface quality have been researched. Firstly, the properties parameters of abrasive media such as viscous have been figured out with formulas based on the characters of abrasive media. And then the force between abrasive near to the workpiece surface and workpiece has been modeled with fluidics equations and dynamics equations. However, different parameter value leads to different force and different force has different surface quality (Ra) of workpiece. The calculation result is similar to the experiment result to some extent. Obviously, this model is helpful to establish the reasonable process parameters.

Abstract: Magnetic characteristics of three magnetic polishing fluids such as magnetic fluid (MF), magnetorheological fluid (MRF), and magnetic compound fluid (MCF) under magnetic field are experimentally investigated and analyzed. Their magnetic cluster structures under action of magnet field are observed, and their magnetic cluster models are established. Magnetic flied assisted polishing experiments for tungsten carbide are developed used these three kinds of magnetic fluids, material removal and surface roughness are respectively measured. At last, the machining characteristic of three magnetic fluids are contrasted and discussed according to experimental results.

Abstract: In this paper, a novel area taking MRF process using permanent magnet as excitation was proposed. Four types of permanent magnet configurations were considered. Polishing experiment was conducted. Effects of different permanent magnet configurations on material removal rate (MRR) were discussed.

Abstract: In order to grasp the microcosmic mechanism of abrasive flow machining (AFM), find out the real law of grain cutting workpiece surface, make out a reasonable process parameters and improve the abrasive flow processing efficiency. The process of grain (near to workpiece surface, called as active grains) cutting workpieces material has been analyzed and the cutting force model has been established in present work. Firstly, at the beginning of the present work, the general process of grain cutting, wearing or deburring workpiece surface has been researched. Theoretical analysis shows that the cutting force not only derives from static force, such as abrasive medium viscoelasticity and grain squeezing, but also dynamic force, such as grain impacting load on the workpiece surface. In ordering to prove the dynamic force exists, one or two main dynamic process parameters (such as abrasive viscosity, extrusion pressure, piston velocity) are chosen, dynamic force is most sensitive to the variation of which, meantime, static force is not, and then the effects of main dynamic process parameters on cutting force value have been compared with the effects of others process parameters by several experiments in the present work. The experimental results show that with the same proportion of variation of process parameters, the change in cutting force (mainly axial cutting force) consists with theoretical results very well in some degree.

Abstract: The aerospace components made of titanium alloy with internal passages have complex geometries and their surface smoothness play an important role on the improvement of fuel efficiency. Hence, a surface finishing method that can produce a conforming surface finish to all internal surface features is required. This paper studies the process characteristics of AFM for Ti-6Al-4V experimentally. In addition, validation of process model based on the tribological interaction between AFM media and Ti-6Al-4V with empirical data is carried out. The theoretical plots agreed well with experimental results on Ø20mmID cylinder although the theoretical plots show over prediction in some conditions.

Abstract: Abrasive medium plays an important role in the application of abrasive flow machining (AFM), a process that finishes complex internal and external geometries. A new abrasive medium needs to be fabricated due to a lack of literature on it. In this work, a new abrasive medium was fabricated by using styrene butadiene rubber (SBR) as carrier and DF-101S was used to study its characterization. Results showed that new abrasive medium with good fluidity and temperature stability was obtained. Processing experiments have also been carried out by using new abrasive medium and MLLD60, and ZYGO was used to study the surface characteristics of the work-piece. Experimental results indicate that the new abrasive medium is applicable to AFM process.

Abstract: KDP crystal (Potassium dihydrogen phosphate single crystal) is extremely difficult to obtain flawless surface because of its soft, brittle, and hygroscopic. And a large amount of time has been spend on obtaining flawless surface with ultra-precision machining methods. In order to quickly reduce surface roughness on KDP crystal, a new micro-deliquescence polishing method with fine water mist was proposed, the polishing tool with fine water mist was designed, and the polishing experiment was carried out. The micro-deliquescence polishing with fine water mist can improve the surface quality of KDP crystal quickly, so it is an effective preprocessing before ultra-precision machining.