Human-centric zero-defect manufacturing: State-of-the-art review, perspectives, and challenges

Zero defect manufacturing (ZDM) aims at eliminating defects throughout the value stream as well as the cost of rework and scrap. The ambitious goal of zero defects requires the extensive utilization of emerging technologies. Amidst the major drive for technological advancement, humans are often kept out of the loop because they are perceived as the root cause of error. The report from the European Commission on Industry 5.0 emphasizes that human-centric is a key pillar in building a more resilient industry and is vital to incorporate the human component into the manufacturing sector. However, we did not find any publications that explain what human-centric ZDM is, nor what the roles of humans are in advancing ZDM. As a contribution to bridging this gap, a systematic literature review is conducted using different databases. We collected 36 publications and categorised them into 3 different human roles which are managers, engineers, and operators. From our search, we found out that managers play a vital role in cultivating ZDM in the entire organization to prevent errors despite the fact they often do not have direct contact with the production line as operators. Operators can help advance ZDM through knowledge capturing with feedback functions to the engineer to better design a corrective action to prevent errors. Assistive technologies such as extended reality are efficient tools used by operators to eliminate human errors in production environments. Human-centric is now a goal in the future manufacturing sector, but it could face barriers such as high technological investments and resistance to changes in their work tasks. This paper can contribute to paving the roadmap of human-centric ZDM to bring defects to zero and reposition the manufacturing sector to become more resilient.publishedVersio

Scheduling for Flexible Production: A Case Study of Production Leveling Under Volume Constraints

Flexible manufacturing systems in high-mix low-volume segments offer many challenges in terms of planning and scheduling. The complexity of these systems often requires a systemic approach for which humans are the perfect actors. However, computer systems can support scheduling tasks more effectively due to their capacity to synthesize large amounts of data. This paper describes a system developed for the flexible manufacturing of wooden doors with a wide range of product configurations. This paper proposes a rule-based scheduling method for high-mix production. The method was applied and validated at a wooden door producer. Based on the company's production schedule for a given week, a scheduling program was developed that suggested minor rearrangements for production leveling. As the rule-based approach makes the decisions verifiable, the program was validated at the producer, through a case study of production leveling under volume constraints. The results include the complete elimination of changeovers and the stabilization of throughput, which improved the precision of the delivery time. The producer is integrating the program into their production planning and control system. Thus, the results suggest that the proposed method can be useful for scheduling high-mix low-volume production, and merits further validation in similar environments.acceptedVersio

Smart Spare Parts Management – A digital supply network perspective

As additive manufacturing (AM) is being utilized across various sectors, value chains are disrupted and new approaches to spare parts management can be adopted. This report provides an introduction to the state-of-the-art regarding AM for the production of spare parts, along with complementary technologies including digital warehouses and distributed manufacturing. Initiatives in certification and qualification are described, and the need for competency is emphasized as a pivotal enabler for the industry to harvest the potential of AM for spare parts management in the coming years.publishedVersio

Studying the Salt Dependence of the Binding of σ70 and σ32 to Core RNA Polymerase Using Luminescence Resonance Energy Transfer

The study of protein-protein interactions is becoming increasingly important for understanding the regulation of many cellular processes. The ability to quantify the strength with which two binding partners interact is desirable but the accurate determination of equilibrium binding constants is a difficult process. The use of Luminescence Resonance Energy Transfer (LRET) provides a homogeneous binding assay that can be used for the detection of protein-protein interactions. Previously, we developed an LRET assay to screen for small molecule inhibitors of the interaction of σ70 with theβ' coiled-coil fragment (amino acids 100–309). Here we describe an LRET binding assay used to monitor the interaction of E. coli σ70 and σ32 with core RNA polymerase along with the controls to verify the system. This approach generates fluorescently labeled proteins through the random labeling of lysine residues which enables the use of the LRET assay for proteins for which the creation of single cysteine mutants is not feasible. With the LRET binding assay, we are able to show that the interaction of σ70 with core RNAP is much more sensitive to NaCl than to potassium glutamate (KGlu), whereas the σ32 interaction with core RNAP is insensitive to both salts even at concentrations >500 mM. We also find that the interaction of σ32 with core RNAP is stronger than σ70 with core RNAP, under all conditions tested. This work establishes a consistent set of conditions for the comparison of the binding affinities of the E.coli sigma factors with core RNA polymerase. The examination of the importance of salt conditions in the binding of these proteins could have implications in both in vitro assay conditions and in vivo function

Conserved residues in the δ subunit help the E. coli clamp loader, γ complex, target primer-template DNA for clamp assembly

The Escherichia coli clamp loader, γ complex (γ3δδ′λψ), catalyzes ATP-driven assembly of β clamps onto primer-template DNA (p/tDNA), enabling processive replication. The mechanism by which γ complex targets p/tDNA for clamp assembly is not resolved. According to previous studies, charged/polar amino acids inside the clamp loader chamber interact with the double-stranded (ds) portion of p/tDNA. We find that dsDNA, not ssDNA, can trigger a burst of ATP hydrolysis by γ complex and clamp assembly, but only at far higher concentrations than p/tDNA. Thus, contact between γ complex and dsDNA is necessary and sufficient, but not optimal, for the reaction, and additional contacts with p/tDNA likely facilitate its selection as the optimal substrate for clamp assembly. We investigated whether a conserved sequence—HRVW279QNRR—in δ subunit contributes to such interactions, since Tryptophan-279 specifically cross-links to the primer-template junction. Mutation of δ-W279 weakens γ complex binding to p/tDNA, hampering its ability to load clamps and promote proccessive DNA replication, and additional mutations in the sequence (δ-R277, δ-R283) worsen the interaction. These data reveal a novel location in the C-terminal domain of the E. coli clamp loader that contributes to DNA binding and helps define p/tDNA as the preferred substrate for the reaction

Transcriptional control in the prereplicative phase of T4 development

Control of transcription is crucial for correct gene expression and orderly development. For many years, bacteriophage T4 has provided a simple model system to investigate mechanisms that regulate this process. Development of T4 requires the transcription of early, middle and late RNAs. Because T4 does not encode its own RNA polymerase, it must redirect the polymerase of its host, E. coli, to the correct class of genes at the correct time. T4 accomplishes this through the action of phage-encoded factors. Here I review recent studies investigating the transcription of T4 prereplicative genes, which are expressed as early and middle transcripts. Early RNAs are generated immediately after infection from T4 promoters that contain excellent recognition sequences for host polymerase. Consequently, the early promoters compete extremely well with host promoters for the available polymerase. T4 early promoter activity is further enhanced by the action of the T4 Alt protein, a component of the phage head that is injected into E. coli along with the phage DNA. Alt modifies Arg265 on one of the two α subunits of RNA polymerase. Although work with host promoters predicts that this modification should decrease promoter activity, transcription from some T4 early promoters increases when RNA polymerase is modified by Alt. Transcription of T4 middle genes begins about 1 minute after infection and proceeds by two pathways: 1) extension of early transcripts into downstream middle genes and 2) activation of T4 middle promoters through a process called sigma appropriation. In this activation, the T4 co-activator AsiA binds to Region 4 of σ70, the specificity subunit of RNA polymerase. This binding dramatically remodels this portion of σ70, which then allows the T4 activator MotA to also interact with σ70. In addition, AsiA restructuring of σ70 prevents Region 4 from forming its normal contacts with the -35 region of promoter DNA, which in turn allows MotA to interact with its DNA binding site, a MotA box, centered at the -30 region of middle promoter DNA. T4 sigma appropriation reveals how a specific domain within RNA polymerase can be remolded and then exploited to alter promoter specificity

Hvordan implementere Plan for lindring ved livets sluttfase, på sykehjem ?

Dette fagutviklingsprosjektet er en avsluttende skriftlig eksamen for meg som student ved videreutdanning i palliativ sykepleie og har følgende problemstilling; Hvordan implementere Plan for lindring i livets sluttfase, på sykehjem? Egen erfaring fra oppfølging av døende og deres pårørende synes tilfeldig, personavhengig og lite dokumentert. Samhandlingsreformen øker behov for kompetanseheving og Helsedirektoratet viser til at sykehjem skal ha prosedyrer for terminalbehandling og yte tjenester med helhetlig tilnærming. Plan for lindring i livets sluttfase skal hjelpe helsepersonell i å gi helhetlig omsorg til pasienter som er døende og deres pårørende ved å innføre rammer og struktur med det mål å kvalitetssikre behandling, pleie og omsorg. Forskning og teori danner grunnlag for prosjektoppgavens første del. Av forskning har jeg valgt tre artikler som har fokus på kvalitetsutvikling ved livets siste dager og hvor metodene både har kvalitativ og kvantitativ tilnærming for å få større dybde i de funn som er gjort. Av teori har jeg valgt å se nærmere på hospicefilosofi som grunnlag for den helhetlige omsorgen som arbeid med palliativ tilnærming har fått i våre dager. En kort beskrivelse av Plan for lindring i livets sluttfase og teori om implementering er også blitt skildret. Metode for gjennomføring av fagutviklingsprosjektet vil bli omtalt i del to. Ved implementering av Plan for lindring i livets sluttfase, vil anbefalinger fra Kompetansesenter for Lindrende behandling bli vektlagt. Ansatte med pleienær funksjon vil bli inkludert i kompetansehevingsprosjektet og bruk av allerede utarbeidet verktøy vil bli benyttet. Prosjektplanen vil også inneholde beskrivelse av budsjett, etisk refleksjon omkring bruk av behandlingsplan, hvordan evaluering av prosjektet er tiltenkt og drøfting av metode. Del tre tar kort for seg hvordan erfaring fra dette fagutviklingsprosjektet kan videreformidles. Fagutviklingsprosjektets styrke er et tverrfaglig samarbeid som kan kvalitetssikre implementeringsarbeidet. Ressurser og motivasjon ved endringsarbeid ansees å være prosjektets utfordring. Målgruppe er egen arbeidsplass

Geometric Accuracy in Laser- Based Powder Bed Fusion of Polymers: Tolerance optimization by part build orientation

As Additive Manufacturing (AM) enters the manufacturing industry, the technology must adhere to stringent quality demands in terms of dimensional and geometric accuracy. However, due to substantial differences in how these technologies realize three-dimensional geometries, generalization of phenomena across AM technologies proves to be quite difficult. Laser-based Powder Bed Fusion (LB-PBF) is an industrialized AM technology capable of producing functional components and end-use parts. However, to ensure consistent quality for larger production volumes in a mass-customization setting, automated optimization methods and process planning must be developed. This requires valid and reliable data to enable the construction of prediction models. This thesis is centered around the optimization of part build orientation in LB-PBF of polymers (LB-PBF/P) for which a deterministic method is proposed. The proposed method utilize mathematical models for the effect of part build orientation on the accuracy of various geometric features. To this end, an experiment has been conducted to generate data for empirical modeling. Two new models are devised for the prediction of cylindricity and flatness based on the experimental data. Variations within and between production runs in LB-PBF/P obscures the validity of experiments. The first Research Question (RQ) addresses this issue and aims at generating valid data for the subsequent analysis. A matrix layout in four dimensions is developed that enables the control of experimental variables while gauging the effect of part placement and production run. The experimental plan successfully enables the analysis of geometric and dimensional properties as a function of part build orientation. Furthermore, the design makes it possible to characterize the variation within and between different builds. The variation is found to be significant in the y-direction of the build chamber, while x- and z-directions appear to be more stable. The second RQ utilizes the experimental data to reveal the effect of part build orientation on the geometric accuracy of planes and cylinders. First, the data is analyzed, and the conformance of theoretical models is evaluated. This analysis reveals that existing models insufficiently explain the effect of part build orientation on the geometric accuracy of planes and cylinders. Therefore, novel empirical models are proposed to better assimilate the observed behavior. The proposed empirical models differ in shape from the theoretical models which are based on the staircase effect. This indicates that the staircase effect alone cannot precisely predict the accuracy of LB-PBF/P. Moreover, the proposed models may widen the range of allowable orientations while meeting tolerance requirements. Finally, a third RQ aims at developing a deterministic method for optimizing accuracy by part build orientation. Mathematical foundations are provided, and a method is described for identifying optimal part build orientations given the geometric features of the part. The proposed method relies on basic information about constituent geometric features and can be populated with any differentiable function for each identified feature type. Through the identification of critical points in a continuous solution space, the optimal orientations are obtained. The main contributions of this thesis concern the modeling accuracy as an effect of part build orientation where the novel model for cylindricity is particularly disruptive. For future work, the effect of part build orientation on other tolerance characteristics should be investigated, and the work should be extended to other materials and AM technologies. Furthermore, the intelligence of such data and models may be integrated into a digital pipeline for quality assurance throughout the value chain, and the product’s life cycle

Evolutionary algorithms in additive manufacturing systems: Discussion of future prospects

Additive Manufacturing (AM) as a manufacturing process is increasingly implemented in manufacturing and is thus subjected to the high demands of industry. With the industrialization of AM technologies follows demands regarding not only dimensions and tolerances, but also mechanical properties, processing time and cost. The multi-objective optimization problems arising from AM is just another venue where Evolutionary Algorithms (EAs) are applied. This paper attempts to provide an overview of the current role of EAs in AM in order to make a discussion on the future prospects of EAs in the industry