Advanced Materials Research Vols. 76-78

Abstract: This paper reports a systematic investigation of high speed grinding of hard-to-machining of titanium alloys. The ground surfaces were characterized using scanning electron microscopy, and the effects of different grinding parameters on roughness were discussed. A numerical model was established to predict surface roughness based on the evolutionary neural network optimized by Genetic Algorithm (GA). The modeled results were in good agreement with the experimental results.

Abstract: Focusing on the characteristic of hard-to-grind for titanium alloy, experiments were conducted about grinding TC4 titanium alloy under high speed deep grinding (HSDG) condition. The changing of grinding force per unit area with maximum undeformed chip thickness hmax and equivalent cutting thickness aeq are analyzed in this paper. The effect of maximum undeformed chip thickness hmax and specific material removal rate Zw' on specific grinding energy es, material removal mechanism and consumption of grinding power in HSDG process are also discussed. The experiment results reveal that application of HSDG can improve machining efficiency of grinding TC4.

Abstract: With the help of the infrared camera temperature measurement technology, the systemic theoretical analysis and experimental research for temperature field and thermal error distribution in NC grinding machine is provided. Two different situations for temperature field and thermal error distribution are respectively measured while the free and loaded grinding by the new measurement method. The mathematical model of thermal error is built, and it shows that the actual error and the forecasted error from thermal error mathematical model have good comparability.

Abstract: A remote fault diagnosis method for ultrahigh speeding grinding based on multi-agent is presented. The general faults of ultrahigh speed grinding are analyzed and diagnosis model based on multi-agent is established, the dialogue layer, problem decomposition layer, control layer and problem solving layer in the process of diagnosis are studied and the knowledge reasoning model of fault diagnosis is set up based case-based reasoning (CBR) combining rule-based reasoning (RBR). Based on theoretical research, a remote fault diagnosis system of ultrahigh speed grinding is developed. Results of the system running prove the theory is correctness and the technology is feasibility.

Abstract: Grinding temperature is the main factor to limit the improvement of grinding efficiency. The main reason of grinding temperature rise is amount of heat transfer into the workpiece in grinding process. How to determine the proportion ratio, which heat transfers into the workpiece, is the main research issue to the precise machining scholars. In this paper, the heat resistance model is used to analyze the proportional coefficient about how much heat transfer into the grinding wheel, and the factors which to influence this coefficient are discussed. The moving heat source method is used to calculate the temperature field caused by single grain heat source, and the heat integral method is used to calculate the heat contains by the grinding chip, and then the heat proportional coefficients transferring into the chip and workpiece are determined respectively.

Abstract: In this paper, a copper-resin bonded diamond wheel was applied to machine the optical glass on a precision grinder. The process of truing and pre-dressing with ELID (electrolytic in-process dressing) were first carried out for the grinding wheels, then the ELID assisted grinding experiments were conducted with the special fine and coarse grained diamond wheels. The experimental results show that the fine and coarse grained wheels can all generated the smooth surface with the surface roughness in nanometer scale and the coarse grained diamond wheel correlates to the slightly more surface damage than the fine grained diamond wheel, which also proves that the high efficient grinding of the optical glass with a good surface quality can be realized with the coarse grained copper-resin wheel on a precision grinder and the grinding wheels were all well conditioned with the conditioning method presented in this paper.

Abstract: This paper reports a molecular dynamics simulation of chemo-mechanical grinding (CMG) of silicon wafer by controlling the interatomic potential parameters to imitate the chemo-mechanical or mechano-chemical reactions between an abrasive grain and a Si wafer. Some comparisons between diamond grinding and CMG were made by using the proposed simulation model. From the simulation results, reductions of surface damages, wears of abrasive grain and scratching forces in CMG were confirmed to be same as observed in actual experiments by a CeO2 abrasive wheel, and the availability of proposed simulation model was verified.

Abstract: High precision mold grinding technique to obtain mirror surface is required which realizes minimization or omission of final polishing by skilled workers. In the previous reports, ultrasonic diamond grinding experiments were carried out to confirm ultrasonic oscillation effect for die steel face grinding. Smooth and glossy surfaces were obtained successfully and little abrasive worn out was found. In the above techniques require cutting edge truncation because the cutting edge shape of a tool affects the ground surface resulting from transcription of cutting edge. This paper describes optimization techniques for the cutting edge truncation of diamond electroplated tools which are used in ultrasonically assisted grinding. Experiments were carried out to confirm truncation effects on the ground surface and grinding force. It was confirmed that roughness was proportional to inverse of thrust force. Minimum roughness in grinding conditions were estimated from the proportional diagrams. The minimum roughness shows limit of roughness on an each grinding condition.

Abstract: The grindactivity of wheel is remarkably lost by the loading of wheel surface in dry grinding of hard carbon parts. In this report, we propose the dressless wheel treatment, in which loading chips are removed with adhesive tape, and experimentally investigate its effect on recovery of grindactivity, analyzing the stock removal, the grinding current and the surface roughness in repeat of grinding cycle with treated and non-treated wheels. The removal and finishing performances of loaded wheel are recovered by the dressless wheel treatment.

Abstract: This paper deals with prediction of improvement in surface roughness in helical scan grinding by simulation of virtual ground surface with a 3D-CAD model. It has been found that, by choosing the value of parameters of four grit conditions such as grit arrangement, protrusion height, apex angle and inclination angle randomly to a real wheel, the maximum unevenness of the virtual ground surface and tendency of its change with feed angle nearly coincide with the surface roughness in the experiment of helical scan grinding. Furthermore, it is demonstrated that this analyzing method can be applied to R-shaped groove grinding and suggested that helical scan grinding is effective in grinding bearing grooves.