Substructure Coupling of Microend Mills to Aid in the Suppression of Chatter

2008 ◽  
Vol 130 (1) ◽  
Author(s):  
Brock A. Mascardelli ◽  
Simon S. Park ◽  
Theodor Freiheit
Keyword(s):  
Finite Element ◽  
Complex Geometry ◽  
Rotational Dynamics ◽  
Response Functions ◽  
Finite Element Analyses ◽  
Coupling Technique ◽  
Good Surface ◽  
Receptance Coupling ◽  
Milling Tool ◽  
Microend Milling

Microend milling offers the ability to machine microparts of complex geometry relatively quickly when compared with photolithographic techniques. The key to good surface quality is the minimization of tool chatter. This requires an understanding of the milling tool and the milling structure system dynamics. However, impact hammer testing cannot be applied directly to the prediction of tool tip dynamics because microend mills are fragile, with tip diameters as small as 10μm. This paper investigates the application of the receptance coupling technique to mathematically couple the spindle/micromachine and arbitrary microtools with different geometries. The frequency response functions (FRFs) of the spindle/micromachine tool are measured experimentally through impact hammer testing, utilizing laser displacement and capacitance sensors. The dynamics of an arbitrary tool substructure are determined through modal finite element analyses. Joint rotational dynamics are indirectly determined through experimentally measuring the FRFs of gauge tools. From the FRFs, chatter conditions are predicted and verified through micromilling experiments.

scholarly journals Analyzing the Dynamic Characteristics of Milling Tool Using Finite Element Method and Receptance Coupling Method

2019 ◽  
Vol 9 (2) ◽  
pp. 3918-3923
Author(s):  
J. P. Hung ◽  
W. Z. Lin ◽  
K. D. Wu ◽  
W. C. Shih
Keyword(s):  
Finite Element ◽  
Frequency Response ◽  
Dynamic Characteristics ◽  
Coupling Method ◽  
Response Functions ◽  
Original Design ◽  
Frequency Response Functions ◽  
Feeding Mechanism ◽  
Receptance Coupling ◽  
Milling Tool

This study aims to investigate the dynamic characteristics of a milling machine with different head stocks by using finite element (FE) method and receptance coupling analysis (RCA). For this purpose, five full finite element machine models, including vertical column, reformed head stock and feeding mechanism were created. With these models, the tool point frequency response functions were directly predicted. Another approach was the application of the receptance coupling method, in which the frequency response of the assembly milling tool was calculated from the receptance components of the individual substructures through the coupling operation with the interfaces of the feeding mechanism. Results show that a whole machine model with reformed stock has superior dynamic behavior when compared with the original design, by an increment of 10% in the dynamic stiffness. The receptance coupling method was verified to show an accurate prediction of the frequency response functions of the spindle tool when compared with the results obtained from the full FE models. Overall, the proposed methodology can help the designer to efficiently and accurately develop the machine tool structure with excellent mechanical performance.

Chatter Stability of Micro-Milling by Considering the Centrifugal Force and Gyroscopic Effect of the Spindle

2019 ◽  
Vol 141 (11) ◽  
Author(s):  
Xiaohong Lu ◽  
Zhenyuan Jia ◽  
Shengqian Liu ◽  
Kun Yang ◽  
Yixuan Feng ◽  
...  
Keyword(s):  
Centrifugal Force ◽  
High Speed ◽  
Beam Theory ◽  
Milling Process ◽  
System Structure ◽  
Micro Milling ◽  
Gyroscopic Effect ◽  
Good Surface ◽  
Receptance Coupling ◽  
Milling Tool

Abstract In the micro-milling process, the minimization of tool chatter is critical for good surface finish quality. The analysis of chatter requires an understanding of the milling tool as well as the dynamics of milling system structure. Frequency response function (FRF) at the micro-milling tool point reflects dynamic behavior of the whole micro-milling machine–spindle–tool system. However, the tool point FRF of micro-milling cannot be obtained directly through the hammering test. To solve the problem, the authors get the FRF of the spindle system based on the rotating Timoshenko beam theory and the receptance coupling substructure analysis (RCSA), and the bearing characteristics are added into the spindle model through structural modification. Then, the centrifugal force and gyroscopic effect caused by the high-speed rotation of the micro-milling spindle are considered to better simulate the real scenario and increase the accuracy of modal parameters. The method has general usage and can be applied to all the micro-milling tools under which only the spindle dimension, bearing characteristics, and contact parameters need to be changed.

Receptance Coupling for Micro-End-Milling

2012 ◽  
Vol 472-475 ◽  
pp. 2391-2396 ◽  
Author(s):  
Zhen Yu Han ◽  
Xiang Zhang ◽  
Hong Ya Fu ◽  
Ya Zhou Sun
Keyword(s):  
Finite Element ◽  
Complex Shape ◽  
Transfer Functions ◽  
End Milling ◽  
Coupling Model ◽  
Receptance Coupling ◽  
Milling Tool ◽  
Micro End Milling ◽  
Milling Tools ◽  
Test Result

Micro-end-milling tools are suitable for machining miniature parts which have complex shape. As the diameters of tools are too small, cannot directly obtain the frequency response functions (FRFs) through impact hammer test at tool tip. This paper employs Receptance Coupling method (RC), couple the tool tip’s FRFs with machine-toolholder system’s FRF, and then get the micro-end-milling tool’s FRF. Establish the coupling model, then finite element and hammer test of the blank gauge tools are used to obtain the coupling transfer functions (TFs). Then analyze the tool tip model by finite element, couple with the machine-toolholder system hammer test result and coupling transfer functions, finally the micro-end-milling tool’s FRFs are obtained. Through the hammer test of blank gauge tool, the effectiveness and feasibility of RC method are verified. The result shows that the RC method is accurate at micro-end-milling tool in steady state milling.

Substructure Coupling of Micro-End Mills

2006 ◽  
Author(s):  
Brock A. Mascardelli ◽  
Simon S. Park ◽  
Theodor Freiheit
Keyword(s):  
Complex Geometry ◽  
End Milling ◽  
Micro Milling ◽  
Good Surface ◽  
Receptance Coupling ◽  
Micro Parts ◽  
Micro End Milling ◽  
End Mills ◽  
Micro Machine ◽  
Micro Tools

Micro-end milling is an important micro-manufacturing technique which offers the ability to machine micro parts of complex geometry relatively quickly when compared with photolithographic techniques. Key to good surface quality in the micro milling operation is the minimization of tool chatter. This requires an understanding of the system dynamics; the system including both the milling tool and the milling structure. However, owing to the miniature nature of micro end mills whose diameters are as small as 50 micrometers, impact hammer testing cannot be applied directly to predict the dynamics at the tool tip. This paper investigates substructure coupling of the spindle/micro machine and arbitrary micro tools with different geometries. This is done through use of the receptance coupling technique. The frequency response functions (FRFs) of the spindle/micro machine are experimentally measured through impact hammer testing utilizing a laser displacement gauge. The dynamics of an arbitrary tool substructure are determined through modal finite element (FE) analyses. Joint rotational dynamics are indirectly determined through experimentally measuring FRFs of gauge tools. The method also enables designers to come up with the optimum design of tool geometries prior to actual fabrication to prevent chatter vibrations.

Application of Grid-Based Approach for Auto Mesh Generation of Vacuum Chamber

2006 ◽  
Vol 306-308 ◽  
pp. 631-636 ◽  
Author(s):  
Young Jae Park ◽  
H.K. Kim ◽  
Yoon Suk Chang ◽  
Jae Boong Choi ◽  
Young Jin Kim
Keyword(s):  
Finite Element ◽  
Mesh Generation ◽  
Vacuum Chamber ◽  
Complex Geometry ◽  
Industrial Applications ◽  
Cad Model ◽  
Finite Element Analyses ◽  
Mesh Quality ◽  
Modeling Process ◽  
Grid Based

A seamless analysis of complex geometry is one of greatly interesting topic. However, there are still gaps between the industrial applications and fundamental academic studies owing to time consuming modeling process. To resolve this problem, an auto mesh generation program based on grid-based approach has been developed for IT-product in the present study. At first, base mesh and skin mesh are generated using the information of entities which extracted from IGES file. Secondly the provisional core mesh with rugged boundary geometry is constructed by superimposing the skin mesh as well as the base mesh generated from the CAD model. Finally, the positions of boundary nodes are adjusted to make a qualified mesh by adapting node modification and smoothing techniques. Also, for the sake of verification of mesh quality, the hexahedral auto mesh constructed by the program is compared with the corresponding tetrahedral free mesh and hexahedral mapped mesh through static finite element analyses. Thereby, it is anticipated that the grid-based approach can be used as a promising pre-processor for integrity evaluation of various IT-products.

A Preliminary Study on the Mechanics of Ankle-Foot Orthoses: From 3D Laser Scan to Smooth Finite Element Model

2009 ◽  
Author(s):  
Tomas Praet ◽  
Matthieu De Beule ◽  
Sofie Van Cauter ◽  
Benedict Verhegghe
Keyword(s):  
Finite Element ◽  
Complex Geometry ◽  
Element Model ◽  
Foot Orthoses ◽  
Foot And Ankle ◽  
Finite Element Analyses ◽  
The Past ◽  
Ankle Foot Orthoses ◽  
Preliminary Study ◽  
Mechanical Devices

Ankle-foot orthoses or AFO’s are external mechanical devices that support the foot and ankle to assist and improve the gait of patients with muscular and/or neurological problems in the lower leg region. To improve the functionality of these orthoses quite some experimental research projects have been carried out and published in the past. However, only a handful of projects included basic finite element analyses (FEA) [1–3], mainly because of the diversity and complex geometry of the AFO’s. This preliminary study should give raise to a series of detailed finite element analyses based on 3D laser scans of ankle-foot orthoses.

Numerical implementation of finite-element method of control volume using irregular mesh

2010 ◽  
Vol 7 ◽  
pp. 98-108
Author(s):  
Yu.A. Gafarova
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Delaunay Triangulation ◽  
Complex Geometry ◽  
Control Volume ◽  
Test Case ◽  
The Finite Element Method ◽  
Irregular Mesh ◽  
Discrete Analogues ◽  
Element Method

To solve problems with complex geometry it is considered the possibility of application of irregular mesh and the use of various numerical methods using them. Discrete analogues of the Beltrami-Mitchell equations are obtained by the control volume method using the rectangular grid and the finite element method of control volume using the Delaunay triangulation. The efficiency of using the Delaunay triangulation, Voronoi diagrams and the finite element method of control volume in a test case is demonstrated.

Bond Thickness Effects upon Dynamic Behaviour in Adhesive Joints

2010 ◽  
Vol 97-101 ◽  
pp. 3920-3923 ◽  
Author(s):  
Xiao Cong He
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Dynamic Behaviour ◽  
Adhesive Layer ◽  
Adhesive Joints ◽  
Response Functions ◽  
Frequency Range ◽  
Element Analysis ◽  
Cantilevered Beam ◽  
Different Thickness

The influence of adhesive layer thickness on the dynamic behaviour of the single-lap adhesive joints is investigated in this paper. The ABAQUS finite element analysis (FEA) software was used to predict the frequency response functions (FRFs) of the single-lap adhesive joints of different thickness of the adhesive layer. As a reference, the FRFs of a cantilevered beam without joint were investigated as well. It is clear that the FRFs of the four beams are close to each other within the frequency range 0~1000 Hz. It is also found that the composite damping of the single-lap adhesive joint increases as the thickness of the adhesive layer increases.

Design of flexure revolute joint based on compliance and stiffness ellipsoids

2021 ◽  
pp. 095441002110169
Author(s):  
Jing Zhang ◽  
Hong-wei Guo ◽  
Juan Wu ◽  
Zi-ming Kou ◽  
Anders Eriksson
Keyword(s):  
Finite Element ◽  
Single Point ◽  
Synthesis Method ◽  
Nonlinear Finite Element ◽  
Finite Element Analyses ◽  
Rotational Stiffness ◽  
Rotational Angle ◽  
Parameterized Model ◽  
Flexure Joints ◽  
Translational Stiffness

In view of the problems of low accuracy, small rotational angle, and large impact caused by flexure joints during the deployment process, an integrated flexure revolute (FR) joint for folding mechanisms was designed. The design was based on the method of compliance and stiffness ellipsoids, using a compliant dyad building block as its flexible unit. Using the single-point synthesis method, the parameterized model of the flexible unit was established to achieve a reasonable allocation of flexibility in different directions. Based on the single-parameter error analysis, two error models were established to evaluate the designed flexure joint. The rotational stiffness, the translational stiffness, and the maximum rotational angle of the joints were analyzed by nonlinear finite element analyses. The rotational angle of one joint can reach 25.5° in one direction. The rotational angle of the series FR joint can achieve 50° in one direction. Experiments on single and series flexure joints were carried out to verify the correctness of the design and analysis of the flexure joint.

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