Design and development of PCD micro straight edge end mills for micro/ nano machining of hard and brittle materials

Xiang Cheng,Zhigang Wang,Kazuo Nakamoto,Kazuo Yamazaki 대한기계학회 2010 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.24 No.11

One of the biggest challenges for mechanical micro/nano milling is the design and fabrication of high precision and high efficiency micro milling tools. Commercially available micro milling tools are either too expensive (around several hundred US dollars) or simply made from downsizing of macro milling tools, which is sometimes not appropriate for the specific micro/nano milling requirements. So the design and fabrication of custom micro milling tools are necessary. In this paper, a micro straight edge endmill (SEE) is designed. Static and dynamic FEM analyses have been done for the SEEs with different rake angles trying to identify their stiffness and natural frequencies. By wire electrical discharge machining (WEDM), the SEEs made of polycrystalline diamond (PCD) with three different rake angles have been fabricated. The evaluation milling on tungsten carbide (WC) and silicon wafer have processed on a nano milling center. Experimental results show the SEEs have a good ability to simultaneously micro/nano milling of both the side and bottom surfaces with submicron surface roughness, and the SEE has high accuracy for large aspect ratio thin wall machining. The milling experiments on silicon wafer have successfully demonstrated that ductile mode machining was achieved and the coolant played an important role in silicon wafer milling.

Prediction model of the surface roughness of micro-milling single crystal copper

Xiaohong Lu,Liang Xue,Feixiang Ruan,Kun Yang,Steven Y. Liang 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.11

Presently, the demand for single crystal copper micro-components is increasing in various fields because single crystal copper has good electrical conductivity. Micro-milling technology is an effective processing technology for small single crystal copper parts. Surface roughness is a key performance indicator for micro-milling single crystal copper. Establishing a surface roughness prediction model with high precision is useful to guarantee the processing quality by selecting the cutting parameters for micro-milling. Few studies have currently focused on micro-milling single crystal copper. In this study, the orthogonal experiments of micro-milling single crystal copper were conducted, and the influences of the spindle and feed speeds and axial depth of cut on the surface roughness of micro-milled single crystal copper with different orientations were analyzed by range analyses. The spindle rotation speed was the major affecting factor. The surface roughness of single crystal copper in different crystal orientations was predicted by using the SVM method. Experimental results showed that the average relative error of the surface roughness of <100>, <110>, and <111> crystal orientation single crystal copper was 2.7 %, 3.3 %, and 2.2 %, respectively, and that the maximum relative errors were 7.0 %. 10.1 %, and 3.1 %, respectively. The uncertainty analysis was conducted by using the Monte Carlo method to verify the reliability of the built surface roughness model.

Cutting parameters optimization for MRR under the constraints of surface roughness and cutter breakage in micro-milling process

Xiaohong Lu,Haixing Zhang,Zhen-yuan Jia,Yixuan Feng,Steven Y. Liang 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.7

Selection of cutting parameters in micro-milling operations is essential for improving machining efficiency and quality, and prolonging the micro-milling tool life. The increase of material removal rate (MRR) always means the increase of cutting parameters, which may lead to poor surface quality and micro-milling tool failure, even cutter breakage. An optimization approach based on genetic algorithm is used to achieve the maximum MRR under the constraints of surface roughness and cutter breakage. A theoretical model for predicting micro-milling cutter breakage is presented and micro-milling experiments were conducted to establish statistical models of cutter breakage and surface roughness. The optimized results were achieved under the constraints of the specified surface roughness and compared under the different surface roughness limitation. We find that the optimized results improve the machining efficiency and quality in micro-milling and is affected by constraint conditions complicatedly.

Experimental research on micro mill-grinding AISI 1045 steel with a cold spraying compound micro cutting tool

Xuelong Wen,Yadong Gong,Chao Wang 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.12

Micro mill-grinding is a novel compound machining process. This article presented a novel micro mill-grinding tool fabricated by cold spray technology. Compound tools with various grit sizes were used in sidewall machining and slotting. It is proved the effect of micro mill-grinding is better in sidewall machining. The machined surface topography and roughness were measured and the results were compared with those of micro milling. It shows that the smaller the grit size is, the smaller the surface roughness is, and the surface textures by compound tools also get tinier and denser with the decrease of the grit size. The influences of processing parameters on sidewall machining were investigated. It is found that surface roughness increases with the increase of cutting depth and feed rate, but decreases with the increase of spindle speed. The plastic deformation was found in the experiments by different machining methods, but there was no microstructure alternation. The plastic deformation of the specimen surface layer is smaller with the high cutting speed and slow feed speed in micro mill-grinding. The microhardness of the processed surface in micro milling-grinding is larger than that in micro-milling. The major wear mode of the micro mill-grinding tools is grit shedding or coating peeling off.

마이크로 밀링을 이용한 미세유로가공에서 미세버 저감방안에 관한 연구

구민수,김영준,박강휘,김정석 한국생산제조학회 2017 한국생산제조학회지 Vol.26 No.6

Micro-burrs deteriorate machined surface quality and cause damage to the contact surfaces of parts; therefore, they should be removed through the deburring process. However, micro-burrs are not easy to remove, making it necessary to suppress the generation of micro-burrs by optimizing the machining process and advanced methodology. In this paper, an effective machining method to suppress micro- burrs and the relationship between burr size and cutting signals were investigated in the micro-milling process. In order to derive a machining method to minimize the generation of micro-burrs, a micro-channel was machined by a total of four machining methods, the size of the exit burr and top burr were measured, and an effective machining method was selected in based on the analysis of micro-burr generation. The relationship between the micro-burrs and the AE signals was determined by an analysis of cutting signals and micro-burr shape.

Experimental study of micro-milling mechanism and surface quality of a nickel-based single crystal superalloy

Qi Gao,Yadong Gong,Yunguang Zhou,Xuelong Wen 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.1

Micro-milling is widely used as a method for machining of micro-parts with high precision and efficiency. Taking the nickel-based single-crystal superalloy DD98 as the research object, the crystal characteristics of single-crystal materials were analysed, and the removal mechanism of single-crystal micro-milled parts was described. Based on molecular dynamics, a simulation model for nickel-based single-crystal superalloy DD98 micro-milling was established. Based on the response surface method of central composite design, the influences of spindle speed, feed rate, and milling depth on the surface roughness were examined, and a second-order regression model of the DD98 surface roughness was established. Using analysis of variance and the residuals of the model, a significant influence on surface roughness was found in the following order from large to small: Feed rate, spindle speed, and milling depth. Comparisons were conducted between the micro-milling experimental values and the predicted model values for different process parameters. The results show that the model fit is relatively high, and the adaptability is good. Scanning electron microscopy analysis of the micro-milling surfaces was performed to verify the slip and the removal mechanism of single-crystal materials. These results offer a theoretical reference and experimental basis for micro-milling of single-crystal materials.

Influence of the Worn Tool Affected by Built-Up Edge (BUE) on Micro End-Milling Process Performance: A 3D Finite Element Modeling Investigation

Ali Davoudinejad,Guido Tosello,Massimiliano Annoni 한국정밀공학회 2017 International Journal of Precision Engineering and Vol.18 No.10

Micro milling process has been utilized for several decades due to the flexibility of the process in producing complex components. The small size of the process makes the comprehension of cutting phenomenon details more difficult. This study presents a 3D finite element modeling (3D FEM) approach for the micro end-milling process of Aluminum material (Al6082-T6). 3D FEM simulations are carried out in full slot micro end-milling and contour up milling. The model first implements the actual tool geometry and then the effect of typical built-up edge (BUE) on the milling tool. The influence of BUE on the process performance is investigated by comparing the predicted 3d chip flow shape, burr formation and cutting forces with experiments conducted on an ultra-high precision micro milling center. Simulations indicate that BUE has significant impact on the chip shape and chip load for different teeth engagements. Results prove that also burr height is negatively affected by the presence of BUE. The predicted micro milling cutting forces resulted affected by BUE with different teeth engagements. Analysis of experimental measured forces indicates comparable results in respect to simulated profiles confirming the usefulness of the develop 3D FE modelling approach.

Research on optimization of milling performance of V-groove micro-texture ball-end milling cutter

Shucai Yang,Chaoyang Guo,Wei Ren 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.6

Titanium alloys generally have problems such as sticking, large cutting force, and poor heat dissipation during the cutting process., research shows that processing microtextures on the surface of the tool can effectively improve the above problems. Therefore, this paper designs the V-groove micro-textures based on the principle of bionics. Use simulation software to analyze the milling behavior of different V-groove micro-texture ball-end milling cutters for milling titanium alloys. Build a test platform to study the milling performance of the Vgroove micro-texture ball-end milling cutter for milling titanium alloys, obtain the prior choice range of V-groove micro-texture parameters, optimize the parameters based on the simulated annealing algorithm and conduct experimental verification. The results of the optimal tool parameters are that the opening angle of the V-groove micro-textures is 79°, the V-groove microtexture spacing is 170 μm, and the V-groove micro-texture width is 30 μm, the distance from blade of the V-groove micro-textures is 90 μm.

Simulation and experiment study of burrs in micro-milling Zr-based metallic glass

Jiachun Wang,Zhenhong Zhang,Chuang Zhang,Jiabin Fu,Jianchao Chen 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.7

Metallic glass has been widely used in making micro parts and equipment due to its excellent physical and chemical performance. A large quantity of burrs is produced in the micro-milling process that is hard to remove and seriously affects the quality and precision of the parts. Burrs should be effectively restrained; however, the burrs’ type, position and the effect of milling parameters on burrs’ generation in micro-milling metallic glass have not been systematically studied. In this paper, by using 3-D FEM simulation and taking micro-milling experiments of Zr-based metallic glass (Vit1), the burrs in flat-end milling and ball-end milling micro grooves were investigated. The burrs’ type and position were observed and summarized, the formation process of various burrs was analyzed in detail, and the influence of cutting parameters on burrs was clarified. Comparing the simulation and experiment result, we could confirm that the top burr and the entrance burr were produced during the processing of the flatend milling cutter, and ball-end milling cutter effectively inhibits the production of the top burr but takes no actions on burrs’ generation at the entrance and the bottom of the groove. The main cause of the top burr is the extrusion of the tool, and the extrusion of the cutting layer metal and chip accumulation were the main reason for entrance and exit burrs. Reducing the axial cutting depth could effectively restrain the generation of burrs for both two kinds of milling tools.

마이크로 엔드밀링시 공구 변형이 가공오차에 미치는 영향에 관한 연구

서태일,손종인,이학용 한국생산제조학회 2009 한국생산제조학회지 Vol.16 No.3

Micro end-milling has been becoming an important machining process to manufacture a number of small products such as micro-devices, bio-chips, micro-patterns and so on. Many related researches have given grand effects to micro end-milling phenomenon, for example, micro end-milling mechanism, cutting force modeling and machinability. This paper strongly concerned actual problem, micro tool deflection, which causes excessive machining errors on the workpiece. Machining error were predicted and measured through a series of test micro cutting and analysis of their SEM images and FEM analysis. Experiments are carried out to validate the approaches.