Qualification and certification of laser powder bed fusion for aerospace applications: a model-based production systems engineering approach.

Date
2023-12
Journal Title
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Publisher
Stellenbosch : Stellenbosch University
Abstract
ENGLISH ABSTRACT: Qualification approaches to aid the certification of additive manufacturing are being widely researched by academia and the aerospace industry due to the potential benefits this technology offers once industrialised. Such benefits include the ability to produce lightweight structures, reduced material waste, the ability to produce unique and complex structures, and production is economical to produce small batches when compared with some traditional manufacturing processes that are reliant on extensive tooling. However, there are challenges hindering the wider adoption of metal additive manufacturing processes in the industry. Such challenges include production controls, data management, process characterisation, material and product traceability, and a general lack of additive manufacturing qualification and certification guidance material, particularly for sub-tiered production and manufacturing organisations. This research aims at developing a production system model that defines the production system lifecycle in terms of qualification and certification, and the standard production operations for laser powder bed fusion production. This model aims at capturing the current additive manufacturing and aerospace production best practices to reduce the steep learning curve that organisations experience when implementing and industrialising new production processes such as laser powder bed fusion. A mixed-method research approach utilising both qualitative and quantitative methods was erformed. A systems engineering methodology was applied which utilised elements of design science research and model-based tools and techniques. Interviews, surveys, observations and benchmarking, and case study research methods were used during the design of conceptual production system models and during model evaluation phases. The production system model was implemented at local industrial and academic facilities. Four test cases were carried out to gather test data and evaluate the production system operation to assess the quality of the developed model. Mechanical and material testing was performed to evaluate the material and articles produced by the developed production system. The developed production system model consists of context and conceptual, operational, logical, physical, and instantiated architectural views. The model addresses production activities from an aerospace part manufacturer and producer perspective, design activities are excluded from the scope of this research. An operational architecture was modelled that defines the production system lifecycle from installation through qualification phases to ongoing production. A production system architecture was modelled that defines the standard laser powder bed fusion production operations. The production system produced material that conforms with industry specification requirements and is comparable to its wrought counterparts. An initial production run of structural components was performed to demonstrate the production system for the full product lifecycle. The use of a model-based system engineering approach for production system design improves information traceability, structuring production facilities, mapping information and material flows, controlling processes and parameters, and implementing production processes. Such aspects are important for achieving qualification and certification in the aerospace industry. Using the model, production and process controls are defined and part quality can be controlled. The developed production system model acts as a single source of truth and a mechanism for communicating production information with stakeholders. The developed architecture and model provide value as a reference for the industry for laser powder bed fusion production. The model can be used as a benchmark for future additive manufacturing and production system development undertakings and for the design and structuring of additive manufacturing quality management systems.
AFRIKAANSE OPSOMMING: Die kwalifikasie van laagvervaardiging prosesse word nagevors deur akademici vir die lugvaart industrie, juis omdat hierdie tegnologie klaarblyklik voordele inhou sodra industrialiseer is. Die voordele sluit die volgende in liggewig strukture, verminderde materiaal vermorsing, unieke en komplekse strukture, en ekonomies om in klein hoeveelhede te produseer in vergeleke met tradisionele vervaardiging waar spesialis gereedskap benodig word. Maar, sekere uitdagings vertraag die groter aanvaarding van laagvervaardiging prosesse in die industrie. Hierdie uitdagings sluit in produksie beheer, informasie bestuur, proses karakterisering, materiaal en produk naspeurbaarheid, en ‘n algemene tekort aan laagvervaardiging kwalifikasie en sertifisering veral vir vervaardigers laer af in die voorsieningsketting. Hierdie navorsing poog om ‘n produksie stelsel model te onwikkel wat die produksie lewens siklus definieer in terme van kwalifikasie en sertifisering van laser poeier bed fusie laagvervaardiging. Die model volg beste praktyke tans bekend in die lugvaart laagvervaardiging industrie, en poog om die leerkurwe om oor te skakel na nuwe vervaardigingsprosesse te verlaag. ’n Gemengde-metode navorsing benadering word gevolg, beide kwalitatief en kwantitatief. Stelselingenieurswese metodiek gebruik dele van ontwerp wetenskap navorsing en model gebaseerde metodes. Die metodes wat tydens die ontwerp van die produksie konsep model en model evaluasie fases gebruik is sluit in onderhoude, vraelyste, observasie, en vergelyking asook gevallestudie. Die produksie stelsel model is by industrie en akademiese fasiliteite implementeer. Vier toetse is uitgevoer om data in te win en produksie proses te evalueer, sodoende die kwaliteit van die konsepmodel te evalueer. Meganiese en materiaal toetse is gebruik om die artikels te evalueer wat deur die stelsel produseer is. Die ontwikkelde stelsel bestaan uit opinies konteks en konsep, operasioneel, logies, fisies, en argitektuur. Die model adresseer die produksie aktiwiteite van ‘n lugvaart part vervaardiger en produseerder, maar ontwerp aktiwiteite word uitgesluit. ‘n Operasionele argitektuur spreek die produksie stelsel lewens siklus aan van installasie tot kwalifikasie. ‘n Produksie stelsel argitektuur definieer die standard laser poeier bed fusie produksie proses. Die produksie stelsel produseer materiaal wat aan industrie standaarde voldoen en vergelykbaar is aan smee prosesse. Aanvanklike strukturele parte is met die stelsel produseer as demonstrator van die produksie stelsel vir die volledige produk lewensiklus. Die gebruik van ‘n model gebaseerde stelselingenieurswese model verbeter informasie naspeurbaarheid, gee struktuur aan produksie fasiliteite, definieer informasie en materiaal vloei patrone, beheer prosesse en parameters en implementeer produksie prosesse. Dit is belangrik vir die sertifisering van lugvaart prosesse. Die model help om produksie en prosesse te definieer om part kwaliteit te beheer. Die ontwikkelde produksie stelsel model staan alleen om as meganisme te dien vir kommunikasie van produksie informasie met belanghebbendes. Die argitektuur en model voeg waarde toe as riglyn vir die industrie oor laser poeier bed fusie produksie. Die model kan as basis gebruik word vir toekomstige laagvervaardiging ontwikkelings waarvoor kwaliteitstelsel ontwerp en struktureer moet word.
Description
Thesis (PhD)--Stellenbosch University, 2023.
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