Fem analysis of micro/meso-scale tooling of a precision unit

Machining vibrations or chatter is an unwanted phenomenon during machining processes due to unwanted machining marks left on the workpiece. To identify feasible machining speed for chatter-free machining, frequency response functions (FRF) of the machine-tool structure is required. However, due to a...

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Main Author: Khor, Jun Onn
Other Authors: Lin Rongming
Format: Final Year Project
Language:English
Published: 2016
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Online Access:http://hdl.handle.net/10356/67923
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Institution: Nanyang Technological University
Language: English
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spelling sg-ntu-dr.10356-679232023-03-04T18:56:06Z Fem analysis of micro/meso-scale tooling of a precision unit Khor, Jun Onn Lin Rongming School of Mechanical and Aerospace Engineering DRNTU::Engineering Machining vibrations or chatter is an unwanted phenomenon during machining processes due to unwanted machining marks left on the workpiece. To identify feasible machining speed for chatter-free machining, frequency response functions (FRF) of the machine-tool structure is required. However, due to almost infinite number of combinations between machine-spindle-toolholder-tool, it is impractical to obtain FRF of each combination by modal testing. Thus receptance coupling substructure analysis (RCSA) is used to reduce the number of modal testing required to be carried out when same machine-spindle-toolholder substructure is reused with other tool configurations. This project derived various RCSA algorithms and verified them using finite element method and experimental testing. RCSA is carried out using the derived algorithms and the process is simplified by using beam theories to substitute finite element analysis (FEA) to obtain free-free FRFs of tools and blanks. Besides that, the complex tool dimensions are also simplified using different analytical models. The prediction from RCSA is then compared to the experiment results obtained from modal testing on similar structure. The assumption of rigid connections between toolholder and tool is also investigated and compared to non-rigid connection assumption, which arises due to the elastic clamping of tool to the toolholders. This assumption states that the two substructures do not have same displacement at the joint location, and the displacement mismatch is compensated by means of springs and dampers between them. The value of the spring stiffness and damping coefficient is unknown, and varies according to different tool or blank configurations. Thus, their relationship with various tool/blank configurations are observed and the relationships are then used to predict values of these coefficients for other tool/blank configurations. The values are then used together with RCSA method to predict the tool point FRFs, and iss compared to the experimental results from modal testing. Bachelor of Engineering (Aerospace Engineering) 2016-05-23T07:19:00Z 2016-05-23T07:19:00Z 2016 Final Year Project (FYP) http://hdl.handle.net/10356/67923 en Nanyang Technological University 99 p. application/pdf
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic DRNTU::Engineering
spellingShingle DRNTU::Engineering
Khor, Jun Onn
Fem analysis of micro/meso-scale tooling of a precision unit
description Machining vibrations or chatter is an unwanted phenomenon during machining processes due to unwanted machining marks left on the workpiece. To identify feasible machining speed for chatter-free machining, frequency response functions (FRF) of the machine-tool structure is required. However, due to almost infinite number of combinations between machine-spindle-toolholder-tool, it is impractical to obtain FRF of each combination by modal testing. Thus receptance coupling substructure analysis (RCSA) is used to reduce the number of modal testing required to be carried out when same machine-spindle-toolholder substructure is reused with other tool configurations. This project derived various RCSA algorithms and verified them using finite element method and experimental testing. RCSA is carried out using the derived algorithms and the process is simplified by using beam theories to substitute finite element analysis (FEA) to obtain free-free FRFs of tools and blanks. Besides that, the complex tool dimensions are also simplified using different analytical models. The prediction from RCSA is then compared to the experiment results obtained from modal testing on similar structure. The assumption of rigid connections between toolholder and tool is also investigated and compared to non-rigid connection assumption, which arises due to the elastic clamping of tool to the toolholders. This assumption states that the two substructures do not have same displacement at the joint location, and the displacement mismatch is compensated by means of springs and dampers between them. The value of the spring stiffness and damping coefficient is unknown, and varies according to different tool or blank configurations. Thus, their relationship with various tool/blank configurations are observed and the relationships are then used to predict values of these coefficients for other tool/blank configurations. The values are then used together with RCSA method to predict the tool point FRFs, and iss compared to the experimental results from modal testing.
author2 Lin Rongming
author_facet Lin Rongming
Khor, Jun Onn
format Final Year Project
author Khor, Jun Onn
author_sort Khor, Jun Onn
title Fem analysis of micro/meso-scale tooling of a precision unit
title_short Fem analysis of micro/meso-scale tooling of a precision unit
title_full Fem analysis of micro/meso-scale tooling of a precision unit
title_fullStr Fem analysis of micro/meso-scale tooling of a precision unit
title_full_unstemmed Fem analysis of micro/meso-scale tooling of a precision unit
title_sort fem analysis of micro/meso-scale tooling of a precision unit
publishDate 2016
url http://hdl.handle.net/10356/67923
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