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Joint Interface Effects on Machining System Vibration
KTH, Skolan för industriell teknik och management (ITM), Industriell produktion, Maskin- och processteknologi.
2013 (Engelska)Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
Abstract [en]

Vibration problems are still the major constraint in modern machining processes that seek higher material removal rate, shorter process time, longer tool life and better product quality. Depending on the process, the weaker structure element can be the tool/tool holder, workpiece/fixture or both. When the tool/tool holder is the main source of vibration, the stability limit is determined in most cases by the ratio of length-to-diameter. Regenerative chatter is the most significant dynamic phenomenon generated through the interaction between machine tool and machining process. As a rule of thumb, the ratio between the tool’s overhang length and the tool’s diameter shouldn’t exceed 4 to maintain a stable machining process while using a conventional machining tool. While a longer tool overhang is needed for specific machining operations, vibration damping solutions are required to ensure a stable machining process. Vibration damping solutions include both active and passive damping solutions. In the passive damping solutions, damping medium such as viscoelastic material is used to transform the vibration strain energy into heat and thereby reduce vibration amplitude. For a typical cantilever tool, the highest oscillation displacement is near the anti-node regions of a vibration mode and the highest oscillation strain energy is concentrated at the node of a vibration mode. Viscoelastic materials have been successfully applied in these regions to exhibit their damping property. The node region of the 1st bending mode is at the joint interfaces where the cantilever tools are clamped. In this thesis, the general method that can be used to measure and characterize the joint interface stiffness and damping properties is developed and improved, joint interfaces’ importance at optimizing the dynamic stiffness of the joint interface is studied, and a novel advancing material that is designed to possess both high young’s modulus and high damping property is introduced. In the joint interface characterization model, a method that can measure the joint interface’s stiffness and damping over the full frequency range with only the assembled structure is presented. With the influence of a joint interface’s normal pressure on its stiffness and damping, an optimized joint interface normal pressure is selected for delivering a stable machining process against chatter with a boring bar setting at 6.5 times overhang length to diameter ratio in an internal turning process. The novel advancing material utilizes the carbon nano particles mixed in a metal matrix, and it can deliver both high damping property and high elastic stiffness to the mechanical structure.

Ort, förlag, år, upplaga, sidor
Stockholm: KTH Royal Institute of Technology, 2013. , s. ix, 48
Serie
TRITA-IIP, ISSN 1650-1888 ; 13:05
Nyckelord [en]
Joint Interface, Vibration, Damping, Chatter, Machining, Carbon NanoComposite, PECVD, HiPIMS
Nationell ämneskategori
Teknik och teknologier
Forskningsämne
SRA - Produktion; Järnvägsgruppen - Ljud och vibrationer
Identifikatorer
URN: urn:nbn:se:kth:diva-122392ISBN: 978-91-7501-778-5 (tryckt)OAI: oai:DiVA.org:kth-122392DiVA, id: diva2:622118
Presentation
2013-05-24, Sal M311, Brinellvägen 68, KTH, Stockholm, 10:00 (Engelska)
Opponent
Handledare
Projekt
PoPJIM, HydroMod, XPRES, NanoComfort
Forskningsfinansiär
EU, FP7, Sjunde ramprogrammet, G62241EU, FP7, Sjunde ramprogrammet, G62240XPRES - Initiative for excellence in production researchEU, Europeiska forskningsrådet, E4329
Anmärkning

QC 20130521

Tillgänglig från: 2013-05-21 Skapad: 2013-05-20 Senast uppdaterad: 2015-11-11Bibliografiskt granskad
Delarbeten
1. Joint interface characterization method using frequency response measurements on assembled structures only: theoretical development and experimental validation on a workholding fixture for machining
Öppna denna publikation i ny flik eller fönster >>Joint interface characterization method using frequency response measurements on assembled structures only: theoretical development and experimental validation on a workholding fixture for machining
2015 (Engelska)Ingår i: The International Journal of Advanced Manufacturing Technology, ISSN 0268-3768, E-ISSN 1433-3015, Vol. 77, nr 5-8, s. 1213-1228Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

A computation model based on inverse receptance coupling method is presented in this paper aiming for obtaining the joint interface's stiffness and damping properties using frequency response functions measured on assembled structures only. In the model, it is emphasized that the joint stiffness and damping should be modeled with frequency dependency. The model's validity is checked both through finite element (FE) simulation and experimental analyses. In the FE simulation example, the computation model gives more accurate results with noise-free data. In the experimental example, where noise in the data is unavoidable, the computation model is explored further for its applicability in the real industrial environment. Results from applications of the computational model show that it is even capable of obtaining the joint interface stiffness and damping values over the structure's resonance frequency. A viable process of predicting behaviors of workpiece with receptance coupling method through identifying the joint interface properties is presented in the end of the paper. The applicability of this computation model and the factors that influence the accuracy of the model are discussed in the end of the paper.

Nyckelord
Joint interface, Joint stiffness, Joint damping, Frequency response functions, Receptance coupling method, Inverse receptance coupling method, Finite element method
Nationell ämneskategori
Produktionsteknik, arbetsvetenskap och ergonomi
Forskningsämne
Industriell produktion; Maskinkonstruktion
Identifikatorer
urn:nbn:se:kth:diva-163992 (URN)10.1007/s00170-014-6539-3 (DOI)000350120000036 ()2-s2.0-84925467019 (Scopus ID)
Forskningsfinansiär
EU, FP7, Sjunde ramprogrammet, 260048
Anmärkning

QC 20150427

Tillgänglig från: 2015-04-27 Skapad: 2015-04-13 Senast uppdaterad: 2017-12-04Bibliografiskt granskad
2. Improving machining performance against regenerative tool chatter through adaptive normal pressure at the tool clamping interface
Öppna denna publikation i ny flik eller fönster >>Improving machining performance against regenerative tool chatter through adaptive normal pressure at the tool clamping interface
2013 (Engelska)Ingår i: Journal of Machine Engineering, ISSN 1895-7595, Vol. 13, nr 1, s. 93-105Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Chatter in machining process is one of the common failures of a production line. For a cantilever tool, such as a boring bar, the rule of thumb requires the overhang length of the tool to be less than 4 times the diameter. The reason is because longer overhang will induce severe tool vibration in the form of chatter during machining. When a longer overhang than 4 times diameter is necessary for performing special machining operations, damping methods are needed to suppress tool chatter. One of the methods is the constrained layer damping method. Materials, such viscoelastic material, are applied in the vibration node regions of the structure to absorb the concentrated vibration strain energy and transform the mechanical energy to heat. With a cantilever tool clamped in a tool holder, the clamping interface is usually the vibration node region. The friction in the joint interface with low normal pressure became another source of damping and can be used for tool chatter suppression in mechanical structures. Joint interfaces are well known to possess normal pressure dependent stiffness and damping. The normal pressure’s effect on the structures frequency response function had been observed by H. Åkesson [1] et al, and L.Mi [2] et al. However, the direct effect of the joint interface normal pressure on machining process stability hasn’t been investigated. In this paper, a cantilever tool with 6.5 overhang length to diameter ratio is investigated. The direct effect of the tool clamping interface’s normal pressure on the machining process stability is studied. Three different levels of clamping normal pressure are tested with an internal turning process. The machining results indicate another adaptable solution on shop floor for suppressing tool chatter.

Ort, förlag, år, upplaga, sidor
Poland: , 2013
Nyckelord
chatter, tool, internal turning, vibration, clamping, damping, interface
Nationell ämneskategori
Produktionsteknik, arbetsvetenskap och ergonomi
Forskningsämne
Järnvägsgruppen - Ljud och vibrationer; SRA - Produktion
Identifikatorer
urn:nbn:se:kth:diva-122424 (URN)
Projekt
POPJIMXPRES
Forskningsfinansiär
XPRES - Initiative for excellence in production researchEU, FP7, Sjunde ramprogrammet, FoF.NMP.2010-1
Anmärkning

QC 20130521

Tillgänglig från: 2013-05-21 Skapad: 2013-05-21 Senast uppdaterad: 2015-11-11Bibliografiskt granskad
3. Anti-vibration Engineering in Internal Turning Using a Carbon Nanocomposite Damping Coating Produced by PECVD Process
Öppna denna publikation i ny flik eller fönster >>Anti-vibration Engineering in Internal Turning Using a Carbon Nanocomposite Damping Coating Produced by PECVD Process
2014 (Engelska)Ingår i: Journal of materials engineering and performance (Print), ISSN 1059-9495, E-ISSN 1544-1024, Vol. 23, nr 2, s. 506-517Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Machining dynamic stability has been enhanced through a damping coating based on a novel carbon-based nanocomposite material. The coating was synthesized using a plasma enhanced chemical vapor deposition method, and deposited on to the round-shank boring bar used for internal turning and tested during machining. Comparisons between an uncoated and a coated boring bar were carried out at 0.25 mm and 0.5 mm depth of cut using a five times length to diameter ratio overhang, which are typical conditions known to generate detrimental mechanical vibrations. From sound pressure measurement it was found that the measured absolute sound level during process could be reduced by about 90% when using the tool coated with damping layer. Surface roughness measurements of the processed workpiece showed decreased Ra values from approximately 3-6 mu m to less than 2 mu m (and in 50% of the cases < 1 mu m) when comparing an uncoated standard tool with its coated counterpart. Moreover, it was found that the addition of an anti-vibration coating did not adversely affect other tool properties, such as rigidity and modularity.

Ort, förlag, år, upplaga, sidor
Springer-Verlag New York, 2014
Nyckelord
chatter, machining, vibration damping, coating, PECVD, HIPIMS, metal matrix composite, carbon nanocomposite
Nationell ämneskategori
Teknisk mekanik Produktionsteknik, arbetsvetenskap och ergonomi Kompositmaterial och -teknik Strömningsmekanik och akustik Nanoteknik Fusion, plasma och rymdfysik
Forskningsämne
Järnvägsgruppen - Ljud och vibrationer; SRA - Produktion
Identifikatorer
urn:nbn:se:kth:diva-122425 (URN)10.1007/s11665-013-0781-y (DOI)000330594800019 ()2-s2.0-84893576587 (Scopus ID)
Projekt
Eurostars Nanocomfort E!4329, Vinnova
Forskningsfinansiär
Vinnova, E!4329XPRES - Initiative for excellence in production research
Anmärkning

QC 20140228. Updated from submitted to published.

Tillgänglig från: 2013-05-21 Skapad: 2013-05-21 Senast uppdaterad: 2017-12-06Bibliografiskt granskad

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