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Improving Machining System Performance through designed-in Damping: Modelling, Analysis and Design Solutions
KTH, School of Industrial Engineering and Management (ITM), Production Engineering, Machine and Process Technology.ORCID iD: 0000-0003-2511-7267
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

With advances in material technology, allowing, for instance, engines to withstand higher combustion pressure and consequently improving performance, comes challenges to productivity. These materials are, in fact, more difficult to machine with regards to tool wear and especially machine tool stability. Machining vibrations have historically been one of the major limitations to productivity and product quality and the cost of machining vibration for cylinder head manufacturing has been estimated at 0.35 euro per part.

The literature review shows that most of the research on cutting stability has been concentrating on the use of the stability limits diagram (SLD), addressing the limitations of this approach. On the other hand, research dedicated to development of machine tool components designed for chatter avoidance has been concentrating solely on one component at the time.

This thesis proposes therefore to extend the stability limits of the machining system by enhancing the structure’s damping capability via a unified concept based on the distribution of damping within the machining system exploiting the joints composing the machine tool structure. The design solution proposed is based on the enhancement of damping of joint through the exploitation of viscoelastic polymers’ damping properties consciously designed as High Damping Interfaces (HDI).

The tool-turret joint and the turret-lathe joint have been analysed. The computational models for dimensioning the HDI’s within these joints are presented in the thesis and validated by the experiments. The models offer the possibility of consciously design damping in the machining system structure and balance it with regards to the needed stiffness.

These models and the experimental results demonstrate that the approach of enhancing joint damping is viable and effective. The unified concept of the full chain of redesigned components enables the generation of the lowest surface roughness over the whole range of tested cutting parameters. The improved machining system is not affected by instability at any of the tested cutting parameters and offers an outstanding surface quality.

The major scientific contribution of this thesis is therefore represented by the proposed unified concept for designing damping in a machining system alongside the models for computation and optimisation of the HDIs.

From the industrial application point of view, the presented approach allows the end user to select the most suitable parameters in terms of productivity as the enhanced machine tool system becomes less sensitive to stability issues provoked by difficult-to-machine materials or fluctuations of the work material properties that may occur in ordinary production processes.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2012. , 79 p.
Series
Trita-IIP, ISSN 1650-1888 ; 12:05
Keyword [en]
Machining performance, Cutting stability, Passive damping, High Damping Interface, Boring bar, Turret
National Category
Production Engineering, Human Work Science and Ergonomics
Research subject
SRA - Production
Identifiers
URN: urn:nbn:se:kth:diva-93143ISBN: 978-91-7501-328-2 (print)OAI: oai:DiVA.org:kth-93143DiVA: diva2:515364
Public defence
2012-05-04, M311, Brinellvägen 68, KTH, Stockholm, 10:00 (English)
Opponent
Supervisors
Projects
DampComatProduction 4 microFFI Robust Machining
Funder
XPRES - Initiative for excellence in production research
Note

QC 20120413

Available from: 2012-04-13 Created: 2012-04-12 Last updated: 2013-04-19Bibliographically approved
List of papers
1. Design, Implementation and Analysis of Composite Material Dampers for Turning Operations
Open this publication in new window or tab >>Design, Implementation and Analysis of Composite Material Dampers for Turning Operations
2009 (English)In: International Conference on Mechanical Engineering, 2009, 613-620 p.Conference paper, Published paper (Refereed)
Abstract [en]

This paper introduces a novel design for boring bar with enhanced damping capability. The principle followed in thedesign phase was to enhance the damping capability minimizing theloss in static stiffness through implementation of composite materialinterfaces. The newly designed tool has been compared to a conventional tool. The evaluation criteria were the dynamic characteristics, frequency and damping ratio, of the machiningsystem, as well as the surface roughness of the machined workpieces.The use of composite material in the design of damped tool has been demonstrated effective. Furthermore, the autoregressive moving average (ARMA) models presented in this paper take in to consideration the interaction between the elastic structure of themachine tool and the cutting process and can therefore be used to characterize the machining system in operational conditions.

Keyword
ARMA, cutting stability, damped tool, machining.
National Category
Mechanical Engineering
Research subject
SRA - Production
Identifiers
urn:nbn:se:kth:diva-28000 (URN)
Conference
ICME International Conference on Mechanical Engineering
Funder
XPRES - Initiative for excellence in production research
Note
QC 20110110Available from: 2011-01-04 Created: 2011-01-04 Last updated: 2012-04-13Bibliographically approved
2. Design and Dynamic Characterization of Composite Material Dampers for Parting-Off Tools
Open this publication in new window or tab >>Design and Dynamic Characterization of Composite Material Dampers for Parting-Off Tools
2010 (English)In: Journal of Machine Engineering, ISSN 1895-7595, Vol. 10, no 2, 57-70 p.Article in journal (Refereed) Published
Place, publisher, year, edition, pages
Wroclaw: Editorial Institution of the Wroclaw Board of Scientific Technical Societies Federation NOT, 2010
Keyword
Damping, Parting-off, Model-based identification, Stability, Operational damping ratio, Operational frequencies
National Category
Mechanical Engineering
Research subject
SRA - Production
Identifiers
urn:nbn:se:kth:diva-27993 (URN)
Funder
XPRES - Initiative for excellence in production research
Note
QC 20110110Available from: 2011-01-04 Created: 2011-01-04 Last updated: 2012-04-13Bibliographically approved
3. Influence of the join system turret-boring bar on machining performance of the cutting process
Open this publication in new window or tab >>Influence of the join system turret-boring bar on machining performance of the cutting process
2010 (English)In: CIRP 2nd International Conference on Process Machine Interactions / [ed] prof. Y. Altintas, Vancouver, 2010Conference paper, Published paper (Refereed)
Abstract [en]

Obtaining the first part correctly is of vital importance. One way of achieving this is to implement solutions with machine tool components that can enable higher removal rates with unchanged or even improved machining performance. A solution is presented in this paper where the principle followed has been to enhance the damping capability of critical structural components of the machine tool (boring bar and turret), minimizing the loss of stiffness. An analytical model of the damping treatment used is presented. The model has been verified by the experimental modal analysis and the machining tests. The introduction of damping in the machine tool structure has been proved to enable machining in stable conditions over a larger range of cutting parameters. The interaction between the cutting process and the machine structure is therefore revealed.

Place, publisher, year, edition, pages
Vancouver: , 2010
Keyword
Turret, damping, flexural rigidity, machining performance
National Category
Engineering and Technology
Research subject
SRA - Production
Identifiers
urn:nbn:se:kth:diva-49760 (URN)978-0-9866331-0-2 (ISBN)
Conference
CIRP 2nd International Conference on Process Machine Interactions. Vancouver, Canada. 10.06.-11.06.2010
Projects
FFI-Robust Maskinbearbetning
Funder
XPRES - Initiative for excellence in production research
Note
QC 20111202Available from: 2011-11-29 Created: 2011-11-29 Last updated: 2012-04-13Bibliographically approved
4. Recursive estimation of machine tool structure dynamic properties
Open this publication in new window or tab >>Recursive estimation of machine tool structure dynamic properties
2010 (English)In: CIRP International Conference on High Performance Cutting, / [ed] Tojiro Aoyama, Yoshimi Takeuchi, Gifu, 2010, 365-370 p.Conference paper, Published paper (Refereed)
Abstract [en]

In today’s highly competitive environment there is a need for fast and accurate methods to assess the capability of manufacturing units. The traditional estimation of the dynamic properties of machine tools is usually time consuming and assumes time-invariant properties. This paper introduces a method for analyzing machine tool structure dynamic properties by recursive estimation of modal and operational parameters. A contact-less excitation system and a specially designed tool were employed to enable spindle speed sweep. The primary contribution of this paper lies within the formulation and implementation of recursive parametric models for tracking the time-varying dynamic properties of a machine tool structure.

Place, publisher, year, edition, pages
Gifu: , 2010
Series
CIRP High Performance Cutting, 4
Keyword
High speed machine tool, Spindle, Recursive estimation, Modal parameters, Operational dynamic parameters, Contact-less excitation system
National Category
Engineering and Technology
Research subject
SRA - Production
Identifiers
urn:nbn:se:kth:diva-27789 (URN)978-4-915698-03-3 (ISBN)
Conference
4th CIRP International Conference on High Performance Cutting, 24-26 October, 2010, Nagaragawa Convention Center, Gifu, Japan
Projects
FFI Robust maskinbearbetning
Funder
XPRES - Initiative for excellence in production research
Note
QC 20110126Available from: 2011-01-26 Created: 2010-12-31 Last updated: 2012-04-13Bibliographically approved
5. Active alignment chuck for ultra precision machining
Open this publication in new window or tab >>Active alignment chuck for ultra precision machining
2011 (English)In: Journal of Machine Engineering, ISSN 1895-7595, Vol. 11, no 4, 39-48 p.Article in journal (Refereed) Published
Abstract [en]

Ultraprecision (UP) components have become common in everyday life products such as mobile phones or compact high resolution digital cameras. Thus the need of producing such components with high accuracy and low production cost. UP machine tools are capable of extremely high accuracy in tool positioning but still today the workpiece is positioned by hand, hence the high production cost of UP components. A fully automated chain of production has been developed within the EU-IP project “Production 4 micro”. This paper describes the active alignment chuck for workholding in UP machining. The chuck has been provided with a high damping interface (HDI) and to evaluate its efficiency the chuck has undergone an experimental modal analysis (EMA) as well as machining tests. The chosen operation was grooving by fly cutting using a diamond tool. The EMA showed that the HDI was effective for those modes where there was relative displacement between one side and the other of the HDI. This result was confirmed by the machining tests as well. The HDI resulted being effective in damping high frequency modes (around 4 – 5 kHz), hence one expected benefit would be a longer tool life.

Place, publisher, year, edition, pages
Wroclaw, Poland: Drukarnia Oficyny Wydawniczej Politechniki Wroclawskiej, 2011
Keyword
Ultraprecision machining, high damping interface, active alignment
National Category
Engineering and Technology
Research subject
SRA - Production
Identifiers
urn:nbn:se:kth:diva-49770 (URN)
Conference
4th International Swedish production symposium. Lund, SWE. 3 - 5 May 2011
Projects
EU - Production for micro
Funder
XPRES - Initiative for excellence in production research
Note

QC 20111202

Available from: 2011-11-29 Created: 2011-11-29 Last updated: 2016-05-04Bibliographically approved

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