scholarly journals Prediction of micro milling force and surface roughness considering size-dependent vibration of micro-end mill

2021 ◽  
Author(s):  
Du Yicong ◽  
Qinghua Song ◽  
Liu Zhanqiang
Keyword(s):  
Surface Roughness ◽  
Size Effect ◽  
Surface Topography ◽  
Milling Process ◽  
Micro Milling ◽  
End Mill ◽  
Milling Force ◽  
Machined Surface ◽  
Size Dependent ◽  
Micro End Mill

Abstract When the characteristic structure size of the component is at the micron level, the internal crystal grains, grain boundaries and pore defects of the component material with the same size at the micron level cannot be ignored, so the micro-sized component will show different physical properties from the macro-sized component, which is called size effect. Since the tool diameter of micro-end mill is in the micron level, the micro-end mill will also show a significant size effect phenomenon. In addition, in micro milling process, because the surface roughness that affects the performance and service life of micro parts is mainly influenced by the vibration of micro-end mill, in order to enhance the machined surface quality, it is crucial to research the formation mechanism of surface topography in micro milling process. In this paper, a comprehensive method is proposed to predict micro-end mill vibration, micro milling force and surface roughness. At first, a size-dependent dynamic model of micro-end mill is presented based on the strain gradient elasticity theory (SGET). Secondly, considering the feedback of micro-end mill vibration, the micro milling force model is presented and solved through iterative method. Then the machined surface topography is simulated through the actual cutting edge trajectory considering the micro-end mill size-dependent vibration and material elastic recovery. The results show that the vibration of the micro-end mill will increase the micro milling force and surface roughness. In order to verify the accuracy and efficiency of the presented method, experiments are performed, and it is found that the experimental results are consistent with the predicted results.

scholarly journals Machinability Research on the Micro-Milling for Graphene Nano-Flakes Reinforced Aluminum Alloy

Metals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1102 ◽  
Author(s):  
Na ◽  
Xu ◽  
Han ◽  
Liu ◽  
Lu
Keyword(s):  
Surface Roughness ◽  
Aluminum Alloy ◽  
Chip Morphology ◽  
Matrix Alloy ◽  
Micro Milling ◽  
Milling Force ◽  
Machined Surface ◽  
Graphene Nanoflakes ◽  
Aluminum Chip ◽  
Powder Metallurgy Approach

In this paper, plain aluminum was chosen as matrix alloy and graphene reinforced aluminum alloy composites was successfully prepared via powder metallurgy approach. Micro-milling experiments were conducted to explore the effect of varying graphene nanoflakes (GNFs) content (0.5%, 1.0%, and 1.5% by weight) on the machinability of composites and their machining results were compared with that of plain aluminum. Chip morphology, milling force, and machined surface morphology were used as the machinability measures. Experiment results showed that when the content of GNFs is less than 1.5%, the grain refinement of GNFs plays a major role. The hardness and density of the composites are increased. When the content of GNFs is more than 1.5%, the agglomeration phenomenon is obvious, which reduces the hardness and density of the composites. Micro-milling results show that the milling force is the highest when the GNFs content is 1%, and curling degree of chips increased as FPT increase for a certain content of graphene of composites. Furthermore, when the content of GNFs in composites is more than 1%, the surface roughness of milling grooves is greatly improved, which may be related to the lubrication of graphene and the formation of continuous chips.

An experimental investigation of micro-milling brass considering run out by carbide micro-end mills

2017 ◽  
Vol 232 (20) ◽  
pp. 3675-3684 ◽  
Author(s):  
Xiubing Jing ◽  
Yanling Tian ◽  
Yanjie Yuan
Keyword(s):  
Surface Roughness ◽  
Cutting Force ◽  
Cutting Speed ◽  
Chip Thickness ◽  
Cutting Parameters ◽  
Milling Process ◽  
Micro Milling ◽  
Method Of Calculation ◽  
Micro End Mill ◽  
End Mills

This paper presented the effect of run out on the experimental characteristic of micro-milling brass using carbide micro-end mills. A method of calculation and measurement for the run out of tool-holder-spindle assembly in micro-end mill was developed. A series of micro-milling process experiments were carried out under varying cutting parameters. The effect of run out on cutting forces, effect of cutting parameters on surface roughness, and size effect were analyzed. It was seen that the cutting force signature was seriously affected by run out in the micro-milling process. When the feed per tooth is less than the run out, the cutting force signals showed that only one cutter flute engaged in cutting process due to the effect of run out. It was also seen that the cutting force signature showed erratic variations due to the effect of tool–workpiece and the run out of tool tip at higher spindle speed. Surface roughness was affected by both cutting speed and feed per tooth. For lower cutting speed, there was increase in the surface roughness with the decrease in the cutting speed due to the effect of built-up edge. For higher cutting speed, there was increase in the surface roughness with the increase in the cutting speed due to dominance of the shearing effects. When the feed per tooth was less than the minimum chip thickness, due to the indentation and ploughing-dominated process, nonlinear increase of specific shear energy can be obtained. At lower feed per tooth, the specific energy increases with increased cutting speed. These results are used to provide strategies to optimize cutting parameters and achieve better surface quality in micro-milling brass process.

Experimental Study on Milling Hardened SKD Steel Using Micro CBN Ball-End Mills

2010 ◽  
Vol 126-128 ◽  
pp. 773-778
Author(s):  
Yung Tien Liu ◽  
Neng Hsin Chiu ◽  
Yen Chun Lin ◽  
Chih Liang Lai ◽  
Yu Fu Lin ◽  
...  
Keyword(s):  
Surface Roughness ◽  
End Milling ◽  
Milling Process ◽  
Micro Milling ◽  
Depth Of Cut ◽  
Machining Accuracy ◽  
Machining Parameters ◽  
Machined Surface ◽  
Performance Function ◽  
End Mills

Micro ball-end milling process features the ability of machining complex surfaces, precision machining accuracy, and excellent machined surface roughness. However, because the diameter of a micro milling tool is very small, a rapid progress of tool wear or even tool breakage usually happens when machining a high-strength hardened mold steel using improper machining parameters. As a result, the machining cost would rise due to the quality defect in machined workpiece. In this study, to investigate how the machining parameters affect the cutting behaviors, a series of experiments using micro CBN ball-end mills with a diameter of 0.5 mm were performed to cut the SKD11 mold steel with hardness of HRC 61. The machining parameters are selected as the feeding speed (f) being 840, 960 and 1,080 mm/min, depth of cut (ap) being 30, 45, 60 μm, and spindle speed (vs) being fixed as 30,000 rpm. According to the experimental results, the measured three-axis cutting forces, flank wears, and surface roughness of machined workpiece are highly related to the cutting length. It is expected that the measured results can be used to construct a performance function of a micro ball-end tool. With referring to the performance function, the tool life can be well expected, and thus a progress in machining efficiency without tool failure can be achieved.

scholarly journals In-situ worn geometry effect over the surface roughness propagation during micro milling process

2020 ◽  
Vol 4 (1) ◽  
pp. 1-7
Author(s):  
Nurul Farhana Mohadzir ◽  
Ainur Munira Rosli ◽  
Ahmad Shahir Jamaludin ◽  
Mohd Nizar Md Razali
Keyword(s):  
Surface Roughness ◽  
Mild Steel ◽  
Milling Process ◽  
Machining Process ◽  
Micro Milling ◽  
Micro Machining ◽  
Cnc Milling ◽  
Machined Surface ◽  
Radial Depth ◽  
Micro Tools

High-precision miniaturized components for micro-machining operations has an increasingly demand for numerous developing sectors such as medical instrumentations, electronics components, computer manufacturing, aerospace and automotive engineering. Micro-milling has known as a flexible micro machining process and the most familiar micro mechanical machining method. Due to overcome a few difficulties in micro fabrication, micro milling is picked as an alternative way as it has potential and imperative for high accuracy machining. However, micro tools have low tool life as it is unpredictably and wear quickly. Furthermore, it also has tendency to break easily due to its micro size dimension. The study observe the behaviour of micro milling worn geometry during machining and includes a non-conventional method to measure surface roughness resulted by micro milling process in machining of mild steel AISI1045. The workpiece is prepared by using CNC milling machine with facing and slotting process. Then, the mild steel AISI1045 will undergo a machining process by a 1 mm size end mill diameter with different set of parameters which are spindle speed, feed rate, radial depth and axial depth. Lastly, for the results, the surface roughness of the machined surface will be observed and the condition of tool and the measurement of wear for the tool will be investigated.

Study on Machining Mechanism of Glass Using Discrete Element Method

2014 ◽  
Vol 577 ◽  
pp. 108-111 ◽  
Author(s):  
Ying Qiu ◽  
Mei Lin Gu ◽  
Feng Guang Zhang ◽  
Zhi Wei
Keyword(s):  
Discrete Element Method ◽  
Element Model ◽  
Discrete Element ◽  
Rake Angle ◽  
Milling Process ◽  
Micro Milling ◽  
Discrete Element Model ◽  
Machined Surface ◽  
Damage Depth ◽  
Element Method

The discrete element method (DEM) is applied to glass micromachining in this study. By three standard tests the discrete element model is established to match the main mechanical properties of glass. Then, indentating, cutting, micro milling process are simulated. Results show that the vertical damage depth is prevented from reaching the final machined surface in cutting process. Tool rake angle is the most remarkable factor influencing on the chip deformation and cutting force. The final machined surface is determined by the minimum cutting thickness per edge. Different cutting thickness, cutter shape and spindle speed largely effect on the mechanism of glass.

Experimental investigation of the influence of cutting parameters on surface quality and on the special characteristics of micro-milled surfaces of hardened steels

2021 ◽  
pp. 095440622110130
Author(s):  
Barnabás Zoltán Balázs ◽  
Márton Takács
Keyword(s):  
Surface Quality ◽  
Surface Profile ◽  
Cutting Parameters ◽  
Relevant Information ◽  
Milling Process ◽  
Micro Milling ◽  
Machined Surface ◽  
Analysis Of Dynamics ◽  
Five Axis ◽  
Coated Carbide

Micro-milling is one of the most essential technologies to produce micro components, but due to the size effect, it has many special characteristics and challenges. The process can be characterised by strong vibrations, relatively large run-out and tool deformation, which directly affects the quality of the machined surface. This paper deals with a detailed investigation of the influence of cutting parameters on surface roughness and on the special characteristics of micro-milled surfaces. Several systematic series of experiments were carried out and analysed in detail. A five-axis micromachining centre and a two fluted, coated carbide micro-milling tool with a diameter of 500 µm were used for the tests. The experiments were conducted on AISI H13 hot-work tool steel and Böhler M303 martensitic corrosion resistance steel with a hardness of 50 HRC in order to gain relevant information of machining characteristics of potential materials of micro-injection moulding tools. The effect of the cutting parameters on the surface quality and on the ratio of Rz/ Ra was investigated in a comprehensive cutting parameter range. ANOVA was used for the statistical evaluation. A novel method is presented, which allows a detailed analysis of the surface profile and repetitions, and identify the frequencies that create the characteristic profile of the surface. The procedure establishes a connection between the frequencies obtained during the analysis of dynamics (forces, vibrations) of the micro-milling process and the characterising repetitions and frequencies of the surface.

Development of the cBN Electroplated End-Mill for High Precision Machining of CFRP

2020 ◽  
Author(s):  
Shinnosuke Yamashita ◽  
Tatsuya Furuki ◽  
Hiroyuki Kousaka ◽  
Toshiki Hirogaki ◽  
Eiichi Aoyama ◽  
...  
Keyword(s):  
Surface Roughness ◽  
End Milling ◽  
Drop Out ◽  
End Mill ◽  
Machined Surface ◽  
Side Milling ◽  
Reinforced Plastics ◽  
Milled Surface ◽  
Grinding Conditions ◽  
Grinding Tool

Abstract Recently, the demand of carbon fiber reinforced plastics (CFRP) has been rapidly increased in various fields. In most cases, CFRP products requires a finish machining like cutting or grinding. In the case of an end-milling, burrs and uncut fibers are easy to occur. On the other hand, a precise machined surface and edge will be able to obtain by using the grinding tool. Therefore, this research has been developed a novel the cBN electroplated end-mill that combined end-mill and grinding tool. In this report, the effectiveness of developed tool was investigated. First, the developed tool cut the CFRP with side milling. As the result, the cBN abrasives that were fixed on the outer surface of developed tool did not drop out. Next, the end-milled surface of CFRP was ground with the developed tool under several grinding conditions based on the Design of Experiment. Consequently, the optimum grinding condition that can obtain the sharp edge which does not have burrs and uncut fibers was found. However, surface roughness was not good enough. Thus, an oscillating grinding was applied. In addition, the theoretical surface roughness formula in case using the developed tool was formularized. As the result, the required surface roughness in the airplane field was obtained.

scholarly journals Cutting Performance of Different Coated Micro End Mills in Machining of Ti-6Al-4V

Micromachines ◽  
2018 ◽  
Vol 9 (11) ◽  
pp. 568 ◽  
Author(s):  
Zhiqiang Liang ◽  
Peng Gao ◽  
Xibin Wang ◽  
Shidi Li ◽  
Tianfeng Zhou ◽  
...  
Keyword(s):  
Tool Wear ◽  
Cutting Edge ◽  
Micro Milling ◽  
End Mill ◽  
Coating Materials ◽  
Edge Chipping ◽  
Workpiece Surface ◽  
Micro End Mill ◽  
End Mills ◽  
Flank Surface

Tool wear is a significant issue for the application of micro end mills. This can be significantly improved by coating materials on tool surfaces. This paper investigates the effects of different coating materials on tool wear in the micro milling of Ti-6Al-4V. A series of cutting experiments were conducted. The tool wear and workpiece surface morphology were investigated by analyzing the wear of the end flank surface and the total cutting edge. It was found that, without coating, serious tool wear and breakage occurred easily during milling. However, AlTiN-based and AlCrN-based coatings could highly reduce cutting edge chipping and flank wear. Specifically, The AlCrN-based coated mill presented less fracture resistance. For TiN coated micro end mill, only slight cutting edge chipping occurred. Compared with other types of tools, the AlTiN-based coated micro end mill could maximize tool life, bringing about an integrated cutting edges with the smallest surface roughness. In short, the AlTiN-based coating material is recommended for the micro end mill in the machining of Ti-6Al-4V.

scholarly journals Experimental Study on Machinability of Zr-Based Bulk Metallic Glass during Micro Milling

Micromachines ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 86 ◽  
Author(s):  
Tao Wang ◽  
Xiaoyu Wu ◽  
Guoqing Zhang ◽  
Bin Xu ◽  
Yinghua Chen ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Feed Rate ◽  
Rotation Speed ◽  
Amorphous Structure ◽  
Micro Milling ◽  
Depth Of Cut ◽  
Milling Force ◽  
Coated Cemented Carbide

The micro machinability of Zr41.2Ti13.8Cu12.5Ni10Be22.5 bulk metallic glass (BMG) was investigated by micro milling with coated cemented carbide tools. The corresponding micro milling tests on Al6061 were conducted for comparison. The results showed that the tool was still in stable wear stage after milling 300 mm, and the surface roughness Ra could be maintained around 0.06 μm. The tool experienced only slight chipping and rubbing wear after milling the BMG, while a built-up edge and the coating peeling off occurred severely when milling Al6061. The influence of rotation speed on surface roughness was insignificant, while surface roughness decreased with the reduction of feed rate, and then increased dramatically when the feed rate was below 2 μm/tooth. The surface roughness increased gradually with the axial depth of cut (DOC). Milling force decreased slightly with the increase in rotation speed, while it increased with the increase in axial DOC, and the size effect on milling force occurred when the feed rate decreased below 1 μm/tooth. The results of X-ray diffraction (XRD) showed that all milled surfaces were still dominated by an amorphous structure. This study could pave a solid foundation for structural and functional applications.

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