Papers by Keyword: Precision Turning

Abstract: One relatively new variant in gear transmissions is the rolling gear boxes. The rolling transmission wheels have variable pitch and variable screw profile surface section. In this paper it is presented the geometry of used helically surfaces and one new machining technology developed by our team. It is used the method of high machining, with high precision turning, which is a promising solution. The profile manufacturing can only be made on high precisions turning. The experimental researches were realized at the Direct-Line Ltd. in Budapest.

Abstract: A modeling method of parts surface form error distribution by precision turning for assembly is proposed in this paper. Selecting cylindrical surface by turning as the research objective, the study of modeling method of form error distribution law is carried out. According to the data from the precision surface which is measured by coordinate measuring machine (CMM), we model form error using the mathematical and numerical simulation software, followed by studying the form error distribution law of the cylindrical surface by precision turning. Finally, the form error numerical model for assembly is established based on the least square method. All the research above can provide guidance for the precision microminiature parts assembly and the improvement of assembly accuracy of precision parts.

Abstract: In this work, the prediction and analysis of cutting forces in precision turning operations is presented. The model of cutting forces is based on the oblique cutting force model which was rebuilt by two coordinate conversions from the orthogonal cutting model. Then the cutting field in precision turning was divided into two fields which are characterized as curve change and linear change on cutter edge and they were modeled respectively. Cutting field of cutter nose was modeled by differential method and its cutting force distribution is predicted by the proposed method. The predicted results for the cutting forces are in agreement with the experimental results under a variety of operation variables, including changes in the depths of cut and in the feedrate.

Abstract: Based on experimental results, a predictive model with certain constraints of cutting parameters (feed rate and depth of cut) and nose radius for cutting forces is solved in precision turning 3J33 alloy. The proposed model is adequate with F-ratio test and multiple correlation coefficient of it. Regression analysis shows that depth of cut and feed rate influence the principal cutting force significantly. The goal of this study is to predict cutting forces under certain constraints of cutting parameters and nose radius.

Abstract: To the processing requirements of high precision small dimension and high surface quality for internal spherical surface with through hole processing, a new technological method of precision turning was proposed in this paper, the processing equipment and control system were designed and developed, the parameters of precision turning technology were given. Through precision turning experiment’s verification, this technological method of precision turning can satisfy processing requirement, and has features of simple, high efficiency, and low processing cost. Some comparative research in various small dimension precision turning technology for internal spherical surface were also made in this paper, and conclusions full of research and processing reference value were drawn.

Abstract: Hard turning has the advantage of rapidly, elasticity and low energy consuming. It has been a trend to replace the complex grinding processes, especially for small batch machining.The surface roughness value of steel after being grinded will ranged in 0.1 to 1.6 μm Ra. This paper points to the precision hard turning of the hardened mold steel, seeking the cutting conditions that can be received in the surface roughness value below 0.1μm Ra, in order to replace the grinding processes. The precision dry turning test were conducted with ceramic cutting tools. The nose radius of the cutting tool was 1.2 mm and the depth of cut was fixed at 0.05 mm. Through a series of turning test, it can be found that, when cutting speed was at 80 to 200 m / min, and feed rate at 0.005 to 0.009 mm / rev, the surface roughness value would be all below 0.1μm Ra. It was superior to grinding process. So we can say that, it is possible to replace the grinding process by hard turning when machining the hardened mold steel.

Abstract: In precision turning, the quality of surface finish is an important requirement for machined workpiece. Thus, the choice of optimal cutting parameters is very important for controlling the required surface quality. The focus of the present study is to find a correlation between surface roughness and cutting parameters (feed rate, depth of cut) and nose radius in turning 3J33 maraging steel, and to derive mathematical models for the predicted surface roughness based on both of cutting parameters and nose radius. The experimental design is carried out using the quadratic rotary combination design. The regression analysis shows feed rate and nose radius influence surface roughness significantly. With F-ratio test the proposed model is adequate. The method could be useful in predicting roughness parameters as a function of cutting parameters and nose radius.

Abstract: In this paper, Based on regression analysis of tests, three comprehensive experimental models were presented in precision turning high-strength spring steel, Vicker’s hardness, residual stresses and surface roughness can be predicted utilizing these models. And the influence of tool geometry on machined surface integrity was analyzed systematically. The analytical results show that Vicker’s hardness and compressive residual stress will increase with the decrease of rake angle, clearance angle, cutting edge angle or minor cutting edge angle, surface roughness increases with an increase of rake angle or clearance angle and decreases with an increase of cutting edge angle or minor cutting edge angle.