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Dynamiskt belastade tribologiska system under plastisk formning, del II --- analyserade genom akustisk emission

Skåre, Thomas LU (2001)
Abstract (Swedish)
Popular Abstract in Swedish

Dynamiska friktions- och ytkontaktförhållanden mellan verktyg och arbetsmaterial vid plastisk formning är svåra att beskriva matematiskt och svåra att övervaka och styra i realtid. Vid höga produktionstempon och högt driven optimering av en formningsoperation ställs stora krav på övervakningsutrustningen. Detta speciellt om formningsprocessens påverkan från variationer härledda till verktyget, materialet och ytkontaktförhållanden mellan arbetsmaterial och verktyg ej kan minimeras och väsentligt påverkar formningsprocessen avseende produktens kvalitet.



Friktionsprocesser kan övervakas med akustisk emission där ''friktionsljudet'' är beroende av bland annat smörjfilmen mellan... (More)
Popular Abstract in Swedish

Dynamiska friktions- och ytkontaktförhållanden mellan verktyg och arbetsmaterial vid plastisk formning är svåra att beskriva matematiskt och svåra att övervaka och styra i realtid. Vid höga produktionstempon och högt driven optimering av en formningsoperation ställs stora krav på övervakningsutrustningen. Detta speciellt om formningsprocessens påverkan från variationer härledda till verktyget, materialet och ytkontaktförhållanden mellan arbetsmaterial och verktyg ej kan minimeras och väsentligt påverkar formningsprocessen avseende produktens kvalitet.



Friktionsprocesser kan övervakas med akustisk emission där ''friktionsljudet'' är beroende av bland annat smörjfilmen mellan materialen. Ljudeffekten ökar vid osmörjda friktionsytor i förhållande till effektivare smörjda ytor. Skillnader i detekterad akustisk emission föreligger också mellan olika smörjmedel, vilket kan användas för en bedömning av smörjmedlets lämplighet i den undersökta applikationen. Akustisk emission erhållen från en formningsoperation innehåller mätbar information från händelser som kallsvetsning, sk ''galling'', verktygsslitage, smörjmedelsfel, stick-slip, veckbildning samt necking och sprickbildning i arbets- eller verktygsmaterialet.



Detekterad akustisk emission är direkt proportionell till den mekaniska effektförbrukningen i en friktionsyta och kan därför användas för att uppskatta friktionsytans belastning. En förändring av triboparametrar som friktionsmaterial, smörjmedlets effektivitet, ytjämnheter, relativa hastigheter mellan materialen och friktionsytornas kontakttryck kan detekteras genom den akustiska emissionen.



Vid montering och injustering av verktygsdelar eller inställning av tillhållarkrafter i en djupdragningsoperation kan variablerna styras mot en minimal detekterad akustisk emission i avsikt att minimera inverkan av gränsskiktsfriktionen och veckbildning. Vidare kan kritiska friktionsytor övervakas med avseende på ytornas förslitning. Den momentana akustiska emissionen innehåller information om friktionsytornas status och förslitningen rör sig mot en inslitning eller en utslitning av materialens ytskikt.



En fortsatt utveckling inom teknikområdet akustisk emission avseende mätmetodik, mätutrustningens prestanda och metodik vid analysering av erhållna resultat bör leda till en ökad tillämpning av mätmetoden i avsikt att övervaka olika formningsmetoder och tillverkningssystem, vilket i sin tur bör leda till nya förutsättningar för ökad produktionskvalitet och en förbättrad produktuppföljning.



Arbetet är uppdelat i två volymer benämnda ''Dynamiskt belastade tribologiska system under plastisk formning, del I --- påverkade genom cyklisk mekanisk spänning'' och ''Dynamiskt belastade tribologiska system under plastisk formning, del II --- analyserade genom akustisk emission''. Del I behandlar ämnesområdena magnetostriktiva aktuatorer, vibrationsassisterade tribosystem och vibrationsassisterad tråddragning. Del II behandlar övervakning av tribologiska system med hjälp av akustisk emission samt akustisk emission från en vibrationspåverkad triboyta. (Less)
Abstract
The dynamic friction process and contact surface between tool and working material in a plastic forming process is hard to describe in mathematical form and hard to monitor and control in real time. High production speed and highly optimised forming operations result in great demands on the control equipment. Especially if the influence from variations due to the tool, work material and the friction surfaces between working material and tool can not be minimised and are essential for the quality of the product.



Friction surfaces can be monitored with acoustic emission (AE) and the AE-signal depends on the lubrication between the friction surfaces. The power of the AE-signal increases with ungreased friction surfaces... (More)
The dynamic friction process and contact surface between tool and working material in a plastic forming process is hard to describe in mathematical form and hard to monitor and control in real time. High production speed and highly optimised forming operations result in great demands on the control equipment. Especially if the influence from variations due to the tool, work material and the friction surfaces between working material and tool can not be minimised and are essential for the quality of the product.



Friction surfaces can be monitored with acoustic emission (AE) and the AE-signal depends on the lubrication between the friction surfaces. The power of the AE-signal increases with ungreased friction surfaces compared in more effectively lubricated surfaces. Differences in detected acoustic emission between different lubricants can be measured and this information can be used to classify different lubricants and the performance in the investigated forming operation. Acoustic emission from a forming operation contains measurable information from events as galling (welded work material on tool), wear of tool, penetration of lubricant, stick-slip, wrinkling necking of sheet material and cracking in tool-material or working material.



The detected acoustic emission is directly proportional to the mechanical power consumption in a friction surface and can therefore be used to estimate the forces on the friction surfaces. A change in the tribological parameters, as material in contact, the efficiency of lubricants, the roughness of the friction surfaces, relative velocity between the friction materials and contact pressure can be monitored with acoustic emission.



Mounting and adjusting of tool parts or correction of holding forces in deep drawing operations can be optimised by minimising acoustic emission due to influence of boundary layer friction and wrinkling. Critical friction surfaces can be monitored with consideration to the wear of the friction surfaces. The momentary acoustic emission contains information about the status of wear at the friction surfaces and if the wear is a wear-in or a wear-out process.



A further development of the acoustic emission monitoring, primarily regarding methodology, the performance of the measurement equipment and methods of analysing measured data, should lead an increased implementation of the method, measuring and monitoring different forming operations and production lines. This will in the end result in new ways to increased production quality and improved quality check.



This work is divided in two volumes, ''Dynamically loaded tribo-systems in plastic forming operations, part I --- actuated by cyclic mechanical stress'' and ''Dynamically loaded tribo-systems in plastic forming operations, part II --- monitored by acoustic emission''.



Part I deal with the subjects magnetostrictive actuators, vibration actuated tribosystems and vibration assisted wire drawing. Part II deals with the monitoring of tribosystems using acoustic emission. (Less)
Please use this url to cite or link to this publication:
author
opponent
  • Professor Magnusson, Claes
organization
alternative title
Dynamically loaded tribo-systems in plastic forming operations, part II --- monitored by acoustic emission
publishing date
type
Thesis
publication status
published
subject
keywords
vibration and acoustic engineering, vacuum technology, hydraulics, Mechanical engineering, supervision, wear, waves, vibrations, tribology, surfaces, stick-slip, sliding, sheet metal, quality check, plastic forming, monitoring, galling, machining, deep drawing, friction, cracking, contact surfaces, Acoustic emission (AE), contact pressure, Maskinteknik, hydraulik, vakuumteknik, vibrationer, akustik, Material technology, Materiallära, materialteknik, Production technology, Produktionsteknik
pages
332 pages
publisher
Viveca Tengå, Div. of Production and Materials Eng., Box 118, S-221 00 LUND, Sweden,
defense location
Lund University, LTH Campus, Building: M, Lecture hall M:B
defense date
2001-06-15 10:15
external identifiers
  • Other:ISRN: LUTMDN/(TMMV-1037)/1-333/(2001)
language
Swedish
LU publication?
yes
id
d9cf4c79-6b0e-4693-ada6-a1424217e08b (old id 20182)
date added to LUP
2007-05-28 08:25:53
date last changed
2016-09-19 08:45:09
@misc{d9cf4c79-6b0e-4693-ada6-a1424217e08b,
  abstract     = {The dynamic friction process and contact surface between tool and working material in a plastic forming process is hard to describe in mathematical form and hard to monitor and control in real time. High production speed and highly optimised forming operations result in great demands on the control equipment. Especially if the influence from variations due to the tool, work material and the friction surfaces between working material and tool can not be minimised and are essential for the quality of the product.<br/><br>
<br/><br>
Friction surfaces can be monitored with acoustic emission (AE) and the AE-signal depends on the lubrication between the friction surfaces. The power of the AE-signal increases with ungreased friction surfaces compared in more effectively lubricated surfaces. Differences in detected acoustic emission between different lubricants can be measured and this information can be used to classify different lubricants and the performance in the investigated forming operation. Acoustic emission from a forming operation contains measurable information from events as galling (welded work material on tool), wear of tool, penetration of lubricant, stick-slip, wrinkling necking of sheet material and cracking in tool-material or working material.<br/><br>
<br/><br>
The detected acoustic emission is directly proportional to the mechanical power consumption in a friction surface and can therefore be used to estimate the forces on the friction surfaces. A change in the tribological parameters, as material in contact, the efficiency of lubricants, the roughness of the friction surfaces, relative velocity between the friction materials and contact pressure can be monitored with acoustic emission.<br/><br>
<br/><br>
Mounting and adjusting of tool parts or correction of holding forces in deep drawing operations can be optimised by minimising acoustic emission due to influence of boundary layer friction and wrinkling. Critical friction surfaces can be monitored with consideration to the wear of the friction surfaces. The momentary acoustic emission contains information about the status of wear at the friction surfaces and if the wear is a wear-in or a wear-out process.<br/><br>
<br/><br>
A further development of the acoustic emission monitoring, primarily regarding methodology, the performance of the measurement equipment and methods of analysing measured data, should lead an increased implementation of the method, measuring and monitoring different forming operations and production lines. This will in the end result in new ways to increased production quality and improved quality check.<br/><br>
<br/><br>
This work is divided in two volumes, ''Dynamically loaded tribo-systems in plastic forming operations, part I --- actuated by cyclic mechanical stress'' and ''Dynamically loaded tribo-systems in plastic forming operations, part II --- monitored by acoustic emission''.<br/><br>
<br/><br>
Part I deal with the subjects magnetostrictive actuators, vibration actuated tribosystems and vibration assisted wire drawing. Part II deals with the monitoring of tribosystems using acoustic emission.},
  author       = {Skåre, Thomas},
  keyword      = {vibration and acoustic engineering,vacuum technology,hydraulics,Mechanical engineering,supervision,wear,waves,vibrations,tribology,surfaces,stick-slip,sliding,sheet metal,quality check,plastic forming,monitoring,galling,machining,deep drawing,friction,cracking,contact surfaces,Acoustic emission (AE),contact pressure,Maskinteknik,hydraulik,vakuumteknik,vibrationer,akustik,Material technology,Materiallära,materialteknik,Production technology,Produktionsteknik},
  language     = {swe},
  pages        = {332},
  publisher    = {ARRAY(0x84d2f20)},
  title        = {Dynamiskt belastade tribologiska system under plastisk formning, del II --- analyserade genom akustisk emission},
  year         = {2001},
}