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High Performance Manufacturing of Advanced Thin Plates ─ Forming of Titanium and Stainless Steel Materials

Gabrielson, Per LU (2014)
Abstract (Swedish)
Popular Abstract in Swedish

I Sverige är tillverkningsindustrin en mycket betydelsefull sektor ur flera aspekter. Dagens ökade krav på tillverkade produkter avseende främst kvalité och prestanda medför samtidigt ökade krav på tillverkningsprocesserna. Syftet med denna avhandling har varit att studera hur en specifik plastisk formningsprocess för avancerade tunnplåtskomponenter kan analyseras, optimeras, övervakas och predikteras samt hur processresultatet kan uttryckas i ekonomiska termer. De aktuella tunnplåtskomponenterna är tillverkade i rostfritt stål eller kommersiellt ren titan och har ett intensivt mönster med en komplex utformning där det är höga toleranskrav på geometri och ytor. En övergripande vision är att... (More)
Popular Abstract in Swedish

I Sverige är tillverkningsindustrin en mycket betydelsefull sektor ur flera aspekter. Dagens ökade krav på tillverkade produkter avseende främst kvalité och prestanda medför samtidigt ökade krav på tillverkningsprocesserna. Syftet med denna avhandling har varit att studera hur en specifik plastisk formningsprocess för avancerade tunnplåtskomponenter kan analyseras, optimeras, övervakas och predikteras samt hur processresultatet kan uttryckas i ekonomiska termer. De aktuella tunnplåtskomponenterna är tillverkade i rostfritt stål eller kommersiellt ren titan och har ett intensivt mönster med en komplex utformning där det är höga toleranskrav på geometri och ytor. En övergripande vision är att kontinuerligt och adaptivt kunna optimera tillverkningsprocessen med avseende på kvalité, processtabilitet, takt och hållbart resursutnyttjande.

För att uppnå visionen har en laboratorieplattform med tillhörande provnings-metodik utvecklats som möjliggör processtudier av kvalitetskritiska formnings-moment. Genom förfarandet kan specifika problem renodlas knutna till formningen av mönstergeometrier under industriella förhållanden. I laboratorie-miljö har kunskaper och erfarenheter byggts upp avseende samband mellan processresultat och styrande faktorer som sedan kunnat implementeras vid industriell tillverkning. I flera fall har även resultat från dessa studier kombinerats med andra förekommande mer traditionella testmetoder för att förenkla eller verifiera erhållna resultat. Genom studier och användning av laboratorie-plattformen har använda materials formbarhet kunnat rangordnas och tilldelas ett formbarhetsindex som senare varit vägledning vid utveckling av nya produkter. Samband och erhållna resultat från ett vidareutvecklat dragprov har bl.a. kunnat knytas till titanmaterialets formbarhet och dess riktningsberoende vid pressning av utvalda mönster eller s.k. plastiska elementarfall. För optimala formnings-förhållanden har även inverkan av utvalda friktionspåverkande parametrar studerats och därmed har även storleken på produktens utgångsämne kunnat predikteras genom kännedom om det globala materialindraget och den lokala materialförtunningen. Forskningen visar på att prestandan för den studerade processen kan förbättras med hjälp av den utvecklade metodiken genom ökad kunskap och kännedom om plåtytornas egenskaper, använt smörjsystem samt plåtmaterialens formbarhet.

Som ett led i denna forskning har också verktygsslitaget med tillhörande mätmetoder utvärderats i laboratoriemiljö. För att erhålla en så låg verktygs-kostnad per producerad detalj som möjligt är det viktigt att verktygsmaterial och beläggning väljs med avseende på kostnad och prestanda. Olika verktygs-lösningar för låg-, mellan- och högvolym har studerats och förhållandet mellan en referensverktygskostnad och ett förslitningsindex presenteras som ett sätt att optimera förhållandet mellan pris och prestanda.

Användning av FE-analyser är en viktig hörnsten i förbättringsarbetet mot en mer högpresterande tillverkningsprocess. Virtuella hjälpmedel kan vara tidseffektiva vid optimering av produkt och process och bidra till en läge detaljkostnad. Laboratorieplattformen har möjliggjort att FE-analyser kunnat verifieras och därmed har även förbättringar av produkt och formningsprocess kunnat implementeras.

Inom arbetet har även ett nytt övervakningssystem baserat på AE (Akustisk Emission) utvecklats och studerats som kan i nära realtid, under formnings-processen, säkerställa kvalitén på den tillverkade detaljen. Systemet möjliggör bl.a. detektering av sprickbildning.

Arbetet behandlar även metoder för att beskriva hela tillverkningsprocessen i ett kostnadsperspektiv. En metod för att analysera produktionsprestanda, med fokus på stillestånd, stilleståndskaraktär samt kostnad per producerad enhet presenteras. Genom framtagen kostnadsmodell har respektive stillestånd och tillhörande orsak kunnat uttryckas i ekonomiska termer. Även det dynamiska stilleståndsbeteendet har studerats ur ett kostnadsperspektiv. Resultaten visar på att det finns betydande potential till förbättringar i hela tillverkningsprocessen och därmed skapa förutsättningarna för en högpresterande tillverkningsprocess. Vidare visar studien att rätt automationsnivå är en viktig faktor för att realisera ett högpresterande tillverkningssystem med långsiktig hållbarhet. För detta presenteras en ekonomisk modell för att bestämma optimal automationsnivå för givna förutsättningar. (Less)
Abstract
The manufacturing industry represents a highly important sector of the Swedish economy. The increasing demands placed on the quality and performance of products that are manufactured places increasing demands on the manufacturing processes involved. The aim of the dissertation has been to study how a particular forming process used in the production of thin sheet-metal parts of advanced character can best be analyzed, optimized, controlled and monitored, and how the processing results can best be predicted and be expressed in economic terms. The sheet-metal parts in question are composed of either stainless steel or pure titanium, formed into complex and intensive patterns, high demands being placed upon their precision of manufacture. An... (More)
The manufacturing industry represents a highly important sector of the Swedish economy. The increasing demands placed on the quality and performance of products that are manufactured places increasing demands on the manufacturing processes involved. The aim of the dissertation has been to study how a particular forming process used in the production of thin sheet-metal parts of advanced character can best be analyzed, optimized, controlled and monitored, and how the processing results can best be predicted and be expressed in economic terms. The sheet-metal parts in question are composed of either stainless steel or pure titanium, formed into complex and intensive patterns, high demands being placed upon their precision of manufacture. An overarching goal was to be able to continuously and adaptively optimize the manufacturing process in terms of quality, process stability, production speed and sustainable resource utilization.

To facilitate achievement of this ultimate goal, a laboratory platform was developed providing the testing methodology needed for process studies of different aspects of forming of critical importance. Use of this platform made it possible to focus on specific problems encountered industrially in the forming of the geometric patterns called for. Under the laboratory conditions created, knowledge and experience concerning relationships between important processing factors and the processing results obtained could be studied. In many cases, the results of the studies carried out could be combined with those obtained through use of more traditional testing methods, either to simplify or to verify results obtained. The laboratory platform and the studies carried out enabled the formability of the different materials involved to be rank-ordered and each of them to be assigned a formability index. The effects of different factors that affect the friction that occurred were also studied with the aim of being determining what forming conditions were optimal. It was found to be possible, with use of the methodology developed and of the increased knowledge and understanding it provided of the sheet-metal surfaces involved, of the lubrication employed, and of the formability of the sheet-metal material in question, to improve the performance of the process that was studied.

Tool wear was assessed in a laboratory platform by means of appropriate measurement techniques. In order to keep the tool cost in an industrial setting as low as possible per part produced, it is important that the tool material and the coating of it employed be selected with adequate attention to both cost and performance. Various tool solutions for low-, medium- and high-volume production were studied. Taking account of the relationship between the costs associated with a reference tool and the wear index that applies can help to optimize the relationship between price and performance.

The use of FE-analysis was seen as an important step in efforts for improvement aimed at creating a high-performance production system. Virtual aids can be useful in this context, contributing to time effectiveness in optimization of both the product in question and the manufacturing process involved. The laboratory platform made it possible to verify the results of the FE-analyses performed, enabling improvements both of the product and of the forming process employed to be implemented.

A new control system that was developed based on use of AE (Acoustic Emission), able during the forming process to ensure virtually in real time the quality of the products being manufactured, was studied, as were various methods for describing the production system as a whole from the standpoint of cost. A method for analyzing production performance in terms of downtimes, in particular their character, effects and the costs per unit produced, was presented. A cost model likewise developed enabled both the downtimes and their causes to be expressed in economic terms. The dynamic downtime behavior of a production system was also studied from a cost perspective. There was found to be considerable potential for improvement of the production process as a whole. It was also shown that selection of the appropriate level of automation is important for achieving a production system having both a high level of performance and long-term sustainability. In connection with this, an economic model was presented for determining the optimal automation level under a given set of conditions. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Professor Rosén, Bengt-Göran, Department of Biomechanics and Mechanical Engineering, Halmstad University, Sweden.
organization
publishing date
type
Thesis
publication status
published
subject
keywords
High performance manufacturing, test tools, sheet-metal forming, stainless steel, commercially pure titanium, process optimization, forming simulation, finite element analyses, acoustic emission, production performance analysis, cost models, manufacturing costs, sustainable production
defense location
Lecture hall M:B, M-building, Ole Römers väg 1, Lund University Faculty of Engineering, Sweden
defense date
2014-04-25 10:00
language
English
LU publication?
yes
id
1ffa1aaa-ebe8-4e52-9df5-f5ae721d2c40 (old id 4378561)
date added to LUP
2014-04-01 09:07:02
date last changed
2016-09-19 08:45:18
@misc{1ffa1aaa-ebe8-4e52-9df5-f5ae721d2c40,
  abstract     = {The manufacturing industry represents a highly important sector of the Swedish economy. The increasing demands placed on the quality and performance of products that are manufactured places increasing demands on the manufacturing processes involved. The aim of the dissertation has been to study how a particular forming process used in the production of thin sheet-metal parts of advanced character can best be analyzed, optimized, controlled and monitored, and how the processing results can best be predicted and be expressed in economic terms. The sheet-metal parts in question are composed of either stainless steel or pure titanium, formed into complex and intensive patterns, high demands being placed upon their precision of manufacture. An overarching goal was to be able to continuously and adaptively optimize the manufacturing process in terms of quality, process stability, production speed and sustainable resource utilization.<br/><br>
To facilitate achievement of this ultimate goal, a laboratory platform was developed providing the testing methodology needed for process studies of different aspects of forming of critical importance. Use of this platform made it possible to focus on specific problems encountered industrially in the forming of the geometric patterns called for. Under the laboratory conditions created, knowledge and experience concerning relationships between important processing factors and the processing results obtained could be studied. In many cases, the results of the studies carried out could be combined with those obtained through use of more traditional testing methods, either to simplify or to verify results obtained. The laboratory platform and the studies carried out enabled the formability of the different materials involved to be rank-ordered and each of them to be assigned a formability index. The effects of different factors that affect the friction that occurred were also studied with the aim of being determining what forming conditions were optimal. It was found to be possible, with use of the methodology developed and of the increased knowledge and understanding it provided of the sheet-metal surfaces involved, of the lubrication employed, and of the formability of the sheet-metal material in question, to improve the performance of the process that was studied.<br/><br>
Tool wear was assessed in a laboratory platform by means of appropriate measurement techniques. In order to keep the tool cost in an industrial setting as low as possible per part produced, it is important that the tool material and the coating of it employed be selected with adequate attention to both cost and performance. Various tool solutions for low-, medium- and high-volume production were studied. Taking account of the relationship between the costs associated with a reference tool and the wear index that applies can help to optimize the relationship between price and performance. <br/><br>
The use of FE-analysis was seen as an important step in efforts for improvement aimed at creating a high-performance production system. Virtual aids can be useful in this context, contributing to time effectiveness in optimization of both the product in question and the manufacturing process involved. The laboratory platform made it possible to verify the results of the FE-analyses performed, enabling improvements both of the product and of the forming process employed to be implemented.<br/><br>
A new control system that was developed based on use of AE (Acoustic Emission), able during the forming process to ensure virtually in real time the quality of the products being manufactured, was studied, as were various methods for describing the production system as a whole from the standpoint of cost. A method for analyzing production performance in terms of downtimes, in particular their character, effects and the costs per unit produced, was presented. A cost model likewise developed enabled both the downtimes and their causes to be expressed in economic terms. The dynamic downtime behavior of a production system was also studied from a cost perspective. There was found to be considerable potential for improvement of the production process as a whole. It was also shown that selection of the appropriate level of automation is important for achieving a production system having both a high level of performance and long-term sustainability. In connection with this, an economic model was presented for determining the optimal automation level under a given set of conditions.},
  author       = {Gabrielson, Per},
  keyword      = {High performance manufacturing,test tools,sheet-metal forming,stainless steel,commercially pure titanium,process optimization,forming simulation,finite element analyses,acoustic emission,production performance analysis,cost models,manufacturing costs,sustainable production},
  language     = {eng},
  title        = {High Performance Manufacturing of Advanced Thin Plates ─ Forming of Titanium and Stainless Steel Materials},
  year         = {2014},
}