Papers by Keyword: Micro-Milling

Abstract: Fabrication of microchannels on titanium alloy with micro-milling is a tough challenge due to the difficultly to remove the burrs formed in machining process. A novel method to gelatinize workpiece surface to control the generation of burr as well as the optimization of cutting parameters are investigated in this paper. Differences existed between the process of micro-milling and that of traditional milling can be accounted for size effect. Influences of feed per tooth, depth of cut and spindle speed on the formation of burr were taken into consideration respectively by single factor method. The topographies of the machined surface with micro-milling were observed and measured by optical microscope. Results showed that the dimensions of burrs increased with the rise of depth of cut. However, it decreased initially, then increased later with the augment of feed per tooth. Sacrifice layer with PMMA was coated and gelatinized on the workpiece surface, which could restrain the plastic deformation of materials during titanium alloy micro-milling. The experimental results presented that the dimensions of burr could reduce greatly by the proposed PMMA coating method compared to materials without coating.

Abstract: This paper present a study of the 2 dimensional ultrasonic vibration assisted micro-milling (UVAM) focused on the tool motion shape and tool trajectory. The cutting characteristics in 2 dimensional are in view by considering the trajectory of the amplitude of vibration towards tool locus into the workpiece during the tool rotation are explore in depth. The vibration platform travel in X_f direction known as a feedrate movement, thus the X and Y axis vibration generate simultaneously through the workpiece surfaces. Amplitude value acting on X and Y axis proposed a major effect as it will effectively change the shape of tool trajectory between oval and eclipse. This investigation found the major advantages of UVAM is come from the alternating cycle’s gap phenomena between tool and workpiece. The reduction of prediction of cutting force and the thinning chip thickness formations has been observe during the investigation. The theoretical finding will be discussing the potential to extended tool life, surface roughness and material removal rate in the conclusion for future research plan.

Abstract: Micro-milling orthogonal experiment of micro plane was done in mesoscale. Probability statistics and multiple regression principle were used to establish the surface roughness prediction model about cutting speed, feed rate and cutting depth, and the significant test of regression equation was done. On the basis of successfully building the prediction model of surface roughness, the diagram of surface roughness and cutting parameters was intuitively built, and then the effect of the cutting speed, feed rate and cutting depth on the small structure surface roughness was obtained.

Abstract: Due to the high precision and strong molding capacity, micro-milling plays an important role in the field of micro-machining. The components machined in micro-machining is smaller than conventional components, and sometimes the generated burrs are as large as the feature size of components, so the study of micro burr control is very important. In the reseach, cutting-direction burrs are based on the traditional milling characteristics, also combined with the characteristics of micro-milling. The experimental data verify the correctness of the model well, so it provides theoretical guidance for the burrs control in micro-milling.

Abstract: Micro cutting offers good potentialities in order to manufacture small and medium lot sizes of micro-parts with arbitrary geometry at an economically reasonable expense. This technology has been widely used in many fields, especially in aerospace field and biological medicine. The slit grating which is used for X-ray telescope is difficult to machine because of the small critical dimensions, large material removal rates and the high requirement of machining quality. In this paper, two methods are describes to manufacture the slit grating which include micro-milling and flying-cutting. The focus is on the design of micro tool, optimization of machining parameters, the comparison of machining efficiency and precision of slit grating by micro-milling and flying-cutting.

Abstract: With the more and more micro mechanical parts are coming into the use of many fields, the micro machining is becoming a new tendency in the future manufacture industry. As a kind of common machining method, milling is also favor in the micro-fabrication field since its good machining precision and forming ability. In this work, cutting process simulation of micro-milling was done to analyze the influence of machining data and tool geometry on the cutting process such as temperature and stress distribution during machining by using ABAQUS software. The results from this simulation can provide some useful information for choosing reasonable cutting edge and machining data to improve surface integrity and prolong cutting tool life in micro-milling operation.

Abstract: This work presents an experimental investigation on micro-milling of fully sintered Zirconia (ZrO₂) with CVD diamond coated end mills. The experiments were conducted on a Kern MMP 2522 micro-milling centre. Diamond coated WC micro end mills with stiff geometry, are employed. Effects of cutting parameters on surface quality were investigated by means of a mixed full factorial experimental design. Surface roughness was measured by a Talysurf 120L profilometer. Surface topography was examined using a scanning electron microscope. The results show that a smaller feed rate was apt to result lower surface roughness. With the increase of cutting length, brittle damages were observed in some tests.

Abstract: Surface roughness plays a critical role in evaluating and measuring the surface quality of a machined product. Two workpiece materials have been investigated by experimental approach in order to gain a better understanding of their influence on the obtained surface roughness in the micro-milling processes. The experimental results show that: surface topography is completely different for different materials at the same cutting speed and feed rate; surface roughness increases with an increase of material grain size. Surface roughness decreases to a lowest value, and then increases with an increase of the feed rate. A new surface model to illustrate the influence of material and uncut chip thickness was developed. The model has been experimentally validated and shows more promising results than Weule’s model.

Abstract: Optical freeform surfaces have a strict request on surface quality, but the vibration of tool , which is often ignored in previous studies, have a great influence on surface topography in micro-milling. This paper constructs a micro-milling motion model concerned with tool vibration, and the impact of tool vibration on feed-interval scallop in micro-milling is analyzed. The results show that tool vibration always lead to an increment of surface roughness; and vibration amplitude and feed per tooth are the major factors that have an effect on feed-interval scallop form and surface quality.

Abstract: This paper presents the vibration and surface roughness issue of poly methyl methacrylate (PMMA) workpiece produced by micro end milling using integrated multi-process machine tools DT 110 (Mikrotools Inc., Singapore) with control parameter; spindle speed, feed rate, and depth of cut. The vibration was measured using accelerometer, DYTRAN Instrument and the average surface roughness Ra was measured using Wyko NT1100. The optimum solution for minimum average vibration is 64.3 Hz with spindle speed 3000 rpm, feed rate 2 mm/min, and depth of cut 1.5 μm. However, the optimum solution for minimum average surface roughness, Ra is 0.352 μm with spindle speed 2000 rpm, feed rate 2 mm/min, and depth of cut 1.5 μm. The micro end milling parameters are suitable to machine PMMA to get good precision surface roughness. The analysis revealed that the feed rate and depth of cut is the most influential parameter on vibration during machining process meanwhile for average surface roughness, Ra spindle speed is the most influential parameter.