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Industrial development of car disassembly - ergonomics and system performance

Kazmierczak, Karolina LU (2005) 17.
Abstract (Swedish)
Popular Abstract in Swedish

Ett nytt EU-direktiv om uttjänta fordon har nyligen antagits. Direktivet kräver att från och med 2006 skall 85% av bilens vikt återvinnas och 95% från och med år 2015. Idag återvinns cirka 80%. Bildemonteringsindustrin har valts som studieobjekt i denna avhandling. De höjda återvinningskraven förväntas leda till att bildemonteringsindustrin genomgår omfattande rationaliseringar och övergår till en modern storskalig produktion. Rationaliserade bildemonteringssystem kan vara ett alternativ till fragmentering. Det övergripande syftet med avhandlingen är att studera kopplingar mellan förväntade rationaliseringar och ergonomi, med bildemonteringsindustrin som exempel. Föreliggande arbete redovisar... (More)
Popular Abstract in Swedish

Ett nytt EU-direktiv om uttjänta fordon har nyligen antagits. Direktivet kräver att från och med 2006 skall 85% av bilens vikt återvinnas och 95% från och med år 2015. Idag återvinns cirka 80%. Bildemonteringsindustrin har valts som studieobjekt i denna avhandling. De höjda återvinningskraven förväntas leda till att bildemonteringsindustrin genomgår omfattande rationaliseringar och övergår till en modern storskalig produktion. Rationaliserade bildemonteringssystem kan vara ett alternativ till fragmentering. Det övergripande syftet med avhandlingen är att studera kopplingar mellan förväntade rationaliseringar och ergonomi, med bildemonteringsindustrin som exempel. Föreliggande arbete redovisar empiri rörande nuvarande produktionssystem och dess prestanda samt ergonomi (belastningar) och framtida utvecklingsmöjligheter.



Representanter från bildemonterings- och tillverkningsindustri samt branschorganisationer beskrev de nuvarande bildemonteringssystemen som ?hantverksmässiga?, dvs. de innehåller många olika arbetsuppgifter och har långa omställningstider. De demonteringsföretag som deltog i studien rapporterade bra lönsamhet. I framtiden förväntas det icke-lönsamma arbetet per bil öka eftersom demontering av mer delar och material som idag saknar marknadsvärde krävs av den nya lagstiftningen. För att bibehålla lönsamheten i produktionen trots mer tid i icke-värde-skapande uppgifter förväntas stora rationaliseringar. För närvarande har Design for Disassembly/Recycling inte tillämpats under tillverkningsfasen, men både demonterare och tillverkare uttryckte behov för strategin, samt samarbete med varandra.



Demonterare i hantverksmässiga systemet rapporterade höga belastningar i armar och ländryggen. Besvären var mest uttalade för ländryggen och 29.5% av operatörerna rapporterade besvär ?ofta? under de senaste 12 månaderna. Besvären var mer uttalade hos demonteringsoperatörer än hos en normalpopulation av män i Sverige. De psykosociala arbetsvillkoren, dvs. krav, inflytande och social stöd var lägre än motsvarande data för den danska yrkespopulationen.



Tekniska mätningar gjordes av belastningar och tidsanvändning i den nuvarande hantverksmässiga svenska bildemonteringen. Demonteringsarbetet innebar höga kardiovaskulära belastningar, mycket gående och höga toppbelastningar på ländryggen. Värdeskapande uppgifter (direkt arbete) utgjorde endast 30% av den totala arbetstiden men medförde mer belastande kroppsställningar och högre rörelsehastigheter för huvud, arm, bål och handled samt mindre tid i vila jämfört med de icke-värdeskapande uppgifterna.



Fysiska belastningar och tidsanvändning undersöktes också i ett ?industriellt? seriellt (linjebaserat) produktionssystem för bildemontering i Holland. Tidsanvändningen i de värdeskapande uppgifterna samt kroppsställningar var likartade i det linjebaserade systemet som i den hantverksmässiga svenska bildemonteringen. Toppbelastningarna tenderade vara mindre i det seriella systemet. Däremot medförde linjesystemet högre rörelsehastigheter för armarna än den hantverksmässiga bildemonteringen.



Det seriella demonteringssystemet hade en del produktionsförluster p.g.a. faktorer som systemförluster, brister i operatörers erfarenhet och lagarbete. För att kunna bedöma konsekvenserna av den alternativa systemdesignen för den fysiska belastningen, presenterades ett nytt sätt att kombinera flödessimulering och biomekanisk simulering. Mindre variation i cykeltider resulterade i högre antal producerade bilar per vecka och högre kumulativ ländryggsbelastning för operatörerna. Å andra sidan resulterade kortare cykeltider i en högre produktivitet utan någon signifikant ändring i användningsgraden och således en oförändrad kumulativ belastning. Kombinerade flöde- och human-simuleringar kan möjliggöra att produktivitet och ergonomi integreras tidigt i systemutvecklingen.



Reliabiliteten hos ett videobaserat verktyg för aktivitetsanalys bedömdes. Aktivitetsanalys var en av huvudmetoderna som användes i detta arbete och det kan användas oftare i framtida studier kring rationalisering. Generellt, var det bra överensstämmelse mellan två observatörer. Variansen mellan filmade personer var större än den mellan observatörerna i de flesta kombinationerna av parameter och aktivitetskategori. En ?övrig? varians, tolkades som inom-observatör variabilitet (test-retest), var generellt större än mellan-observatör variabilitet.



Genom att inkludera representanter från bildemonterings- och tillverkningsindustri, respektive branschorganisationer och berörda myndigheter visar föreliggande avhandling hur forskningsresultat kan överföras till praktik. I samarbetet fanns också utvecklare av det seriella demonteringssystemet och praktiker representerade i en referensgrupp. Kunskapsöverföring från denna forskning till de berörda intressenterna är en grundläggande princip för proaktiv intervention. (Less)
Abstract
A new EU directive on used vehicles has recently been introduced. It demands that for every scrapped car, at least 85% by weight must be recycled by the year 2006 and 95% by 2015. The current level is about 80%. The car disassembly industry was chosen as the study object of this thesis. Due to the increased demands on recycling, the disassembly industry may undergo comprehensive rationalizations and expand into a modern mass-type production. Rationalized car disassembly systems may be an alternative to shredding processes. The general aim of this thesis is to study the connections between expected rationalizations and ergonomics based on the case of the car disassembly industry. The studies in this thesis aim to collect empirical data on... (More)
A new EU directive on used vehicles has recently been introduced. It demands that for every scrapped car, at least 85% by weight must be recycled by the year 2006 and 95% by 2015. The current level is about 80%. The car disassembly industry was chosen as the study object of this thesis. Due to the increased demands on recycling, the disassembly industry may undergo comprehensive rationalizations and expand into a modern mass-type production. Rationalized car disassembly systems may be an alternative to shredding processes. The general aim of this thesis is to study the connections between expected rationalizations and ergonomics based on the case of the car disassembly industry. The studies in this thesis aim to collect empirical data on present production system performance and ergonomics (physical workloads) and possible future development.



Car dismantlers, manufacturers and authority stakeholders described current disassembly systems as ?craft-type?, i.e. containing a rich variety of tasks and considerable periods of set-up time. The dismantling companies reported good profitability. Expectations about production systems in the future were that the amount of non-profit work per car would



increase and more parts and materials than at present will have to be dismantled. These materials lack market value today. For production to stay profitable in spite of increased time in non-value-adding tasks, comprehensive rationalizations were anticipated. Design for Disassembly/Recycling was not fully applied at the manufacturing. However, the need for this strategy was expressed by both dismantlers and manufacturers, as was the need of cooperation between these two groups.



The ?craft-type? disassembly workers reported a high physical workload for the arm and for the low back. Pain levels were highest for the low back, with 29.5% of operators reporting pain to occur ?often? during the last 12 months. Disassembly workers had higher pain scores than a general male population in Sweden. The psychosocial working conditions, i.e. demands, influence and social support were lower than the corresponding data for the Danish working population.



Technical measurements of physical workloads and time consumption in the current ?craft-type? Swedish car disassembly were made. Disassembly work implied high circulatory loads, much walking and high peak low back loads. Value-adding, ?direct?, work comprised only 30% of the total working time, and implied more awkward postures and higher movement velocities for the head, arm, upper back and wrist than non-value adding tasks, as well as less time in rest.



The physical workloads and operators? utilization of time were also assessed in a serial-flow ?industrialized? production system for car disassembly in the Netherlands. Time proportions of direct work as well as body postures were similar in the serial-flow car disassembly and in the Swedish craft-type. Peak low back load tended to be smaller in the serial-flow system, while the upper limb movement velocities appeared to be higher in this system.



The serial-flow disassembly system showed production deficits due to factors such as system losses, worker inexperience and teamwork deficits. A novel combination of flow and biomechanical simulation was presented in order to assess the physical loading consequences of alternative system configurations. A smaller variation in cycle times implied higher output in number of cars per week and larger operator cumulative loading on the low back. Reducing cycle times, on the other hand, resulted in higher output without significant change in utilization rates and thus unchanged cumulative load. Combined human and flow simulations may allow an integrated consideration of productivity and human factors in the early system development.



Reliability of the video-based tool for work task analysis was assessed. Task analysis was one of the core methods used in this research, and it may be more frequently used in ?rationalization? studies. In general, there was good agreement between observers both on overall task proportions and on the mean duration of sequences in most task categories. The variance between filmed subjects was larger than that between observers in most combinations of parameter and task category. The residual variance, interpreted as mainly being due to within-observer (test-retest) variability, was generally larger than the between-observer variability.



This thesis included transfer of research to practice through close cooperation with stakeholders in car disassembly and assembly, their branch organizations and authority stakeholders. The collaboration also included the serial-flow system developer and practitioners through a Reference Group. The transfer of knowledge from this research to the disassembly stakeholders is an underlying principle of the proactive ?intervention?. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Professor de Looze, Michiel P, TNO Work & Employment, The Netherlands
organization
publishing date
type
Thesis
publication status
published
subject
keywords
physical workloads, production systems, muskelsystem, reumatologi, rheumatology locomotion, Skelett, muscle system, Skeleton, flow and human simulations, video-task analysis, rationalizations, car disassembly, musculoskeletal disorders, Technological sciences, Teknik
volume
17
pages
177 pages
publisher
Department of Design Sciences, Faculty of Engineering, Lund University
defense location
Stora hörsalen, Ingvar Kamprad Design Center, Sölvegatan 26, Lund Institute of Technology
defense date
2005-12-15 10:15
ISSN
1650-9773
ISBN
91-628-6595-1
language
English
LU publication?
yes
id
92341610-e1ad-4f79-bc01-d2c4b97278d7 (old id 545848)
date added to LUP
2007-09-10 11:42:25
date last changed
2016-09-19 08:44:54
@phdthesis{92341610-e1ad-4f79-bc01-d2c4b97278d7,
  abstract     = {A new EU directive on used vehicles has recently been introduced. It demands that for every scrapped car, at least 85% by weight must be recycled by the year 2006 and 95% by 2015. The current level is about 80%. The car disassembly industry was chosen as the study object of this thesis. Due to the increased demands on recycling, the disassembly industry may undergo comprehensive rationalizations and expand into a modern mass-type production. Rationalized car disassembly systems may be an alternative to shredding processes. The general aim of this thesis is to study the connections between expected rationalizations and ergonomics based on the case of the car disassembly industry. The studies in this thesis aim to collect empirical data on present production system performance and ergonomics (physical workloads) and possible future development.<br/><br>
<br/><br>
Car dismantlers, manufacturers and authority stakeholders described current disassembly systems as ?craft-type?, i.e. containing a rich variety of tasks and considerable periods of set-up time. The dismantling companies reported good profitability. Expectations about production systems in the future were that the amount of non-profit work per car would<br/><br>
<br/><br>
increase and more parts and materials than at present will have to be dismantled. These materials lack market value today. For production to stay profitable in spite of increased time in non-value-adding tasks, comprehensive rationalizations were anticipated. Design for Disassembly/Recycling was not fully applied at the manufacturing. However, the need for this strategy was expressed by both dismantlers and manufacturers, as was the need of cooperation between these two groups.<br/><br>
<br/><br>
The ?craft-type? disassembly workers reported a high physical workload for the arm and for the low back. Pain levels were highest for the low back, with 29.5% of operators reporting pain to occur ?often? during the last 12 months. Disassembly workers had higher pain scores than a general male population in Sweden. The psychosocial working conditions, i.e. demands, influence and social support were lower than the corresponding data for the Danish working population.<br/><br>
<br/><br>
Technical measurements of physical workloads and time consumption in the current ?craft-type? Swedish car disassembly were made. Disassembly work implied high circulatory loads, much walking and high peak low back loads. Value-adding, ?direct?, work comprised only 30% of the total working time, and implied more awkward postures and higher movement velocities for the head, arm, upper back and wrist than non-value adding tasks, as well as less time in rest.<br/><br>
<br/><br>
The physical workloads and operators? utilization of time were also assessed in a serial-flow ?industrialized? production system for car disassembly in the Netherlands. Time proportions of direct work as well as body postures were similar in the serial-flow car disassembly and in the Swedish craft-type. Peak low back load tended to be smaller in the serial-flow system, while the upper limb movement velocities appeared to be higher in this system.<br/><br>
<br/><br>
The serial-flow disassembly system showed production deficits due to factors such as system losses, worker inexperience and teamwork deficits. A novel combination of flow and biomechanical simulation was presented in order to assess the physical loading consequences of alternative system configurations. A smaller variation in cycle times implied higher output in number of cars per week and larger operator cumulative loading on the low back. Reducing cycle times, on the other hand, resulted in higher output without significant change in utilization rates and thus unchanged cumulative load. Combined human and flow simulations may allow an integrated consideration of productivity and human factors in the early system development.<br/><br>
<br/><br>
Reliability of the video-based tool for work task analysis was assessed. Task analysis was one of the core methods used in this research, and it may be more frequently used in ?rationalization? studies. In general, there was good agreement between observers both on overall task proportions and on the mean duration of sequences in most task categories. The variance between filmed subjects was larger than that between observers in most combinations of parameter and task category. The residual variance, interpreted as mainly being due to within-observer (test-retest) variability, was generally larger than the between-observer variability.<br/><br>
<br/><br>
This thesis included transfer of research to practice through close cooperation with stakeholders in car disassembly and assembly, their branch organizations and authority stakeholders. The collaboration also included the serial-flow system developer and practitioners through a Reference Group. The transfer of knowledge from this research to the disassembly stakeholders is an underlying principle of the proactive ?intervention?.},
  author       = {Kazmierczak, Karolina},
  isbn         = {91-628-6595-1},
  issn         = {1650-9773},
  keyword      = {physical workloads,production systems,muskelsystem,reumatologi,rheumatology locomotion,Skelett,muscle system,Skeleton,flow and human simulations,video-task analysis,rationalizations,car disassembly,musculoskeletal disorders,Technological sciences,Teknik},
  language     = {eng},
  pages        = {177},
  publisher    = {Department of Design Sciences, Faculty of Engineering, Lund University},
  school       = {Lund University},
  title        = {Industrial development of car disassembly - ergonomics and system performance},
  volume       = {17},
  year         = {2005},
}