Lean Production to Increase Reproducibility and Work Safety in the Laser Beam Melting Process Chain

Authors: C. Bay, A. Mahr, H. Groneberg, F. Döpper

Abstract:

Additive Manufacturing processes are becoming increasingly established in the industry for the economic production of complex prototypes and functional components. Laser beam melting (LBM), the most frequently used Additive Manufacturing technology for metal parts, has been gaining in industrial importance for several years. The LBM process chain – from material storage to machine set-up and component post-processing – requires many manual operations. These steps often depend on the manufactured component and are therefore not standardized. These operations are often not performed in a standardized manner, but depend on the experience of the machine operator, e.g., levelling of the build plate and adjusting the first powder layer in the LBM machine. This lack of standardization limits the reproducibility of the component quality. When processing metal powders with inhalable and alveolar particle fractions, the machine operator is at high risk due to the high reactivity and the toxic (e.g., carcinogenic) effect of the various metal powders. Faulty execution of the operation or unintentional omission of safety-relevant steps can impair the health of the machine operator. In this paper, all the steps of the LBM process chain are first analysed in terms of their influence on the two aforementioned challenges: reproducibility and work safety. Standardization to avoid errors increases the reproducibility of component quality as well as the adherence to and correct execution of safety-relevant operations. The corresponding lean method 5S will therefore be applied, in order to develop approaches in the form of recommended actions that standardize the work processes. These approaches will then be evaluated in terms of ease of implementation and their potential for improving reproducibility and work safety. The analysis and evaluation showed that sorting tools and spare parts as well as standardizing the workflow are likely to increase reproducibility. Organizing the operational steps and production environment decreases the hazards of material handling and consequently improves work safety.

Keywords: Additive manufacturing, lean production, reproducibility, work safety.

References:

[1] T. Heß, Beitrag zur Qualifizierung des pulverbettbasierten Laser-strahlschmelzens zur Serienfertigung am Beispiel der Triebwerksin-dustrie. Dissertation, Karlsruher Institute for Technology, Karlsruhe, 2015
[2] O. Rehme, Cellular Design for Laser Freeform Fabrication, Göttingen: Cuvillier Verlag, 2010
[3] T. Sehrt, Möglichkeiten und Grenzen bei der generativen Herstellung metallischer Bauteile durch das Strahlschmelzverfahren, Dissertation, University Duisburg-Essen, 2010
[4] VDI Verein Deutscher Ingenieure/German Association of Engineers, VDI 2870 Part 1:2012: “Lean production systems”, 2012
[5] C. Caviezel et al., Additive Fertigungsverfahren (3-D-Druck), 2017
[6] T. Pereira, J. V. Kennedy, J. Potgieter, “A comparison of traditional manufacturing vs. additive manufacturing, the best method for the job”, Procedia Manufacturing, p. 11–18, 2019
[7] E. Marquart, G. Witt, Handlungsfelder Additiver Fertigungsverfahren, VDI-Verlag, 2019
[8] J. A. Slotwinski, “Additive manufacturing: Overview and NDE challenges” in AIP Conference Proceedings, 40th Annual Review of Progress in Quantitative Nondestructive Evaluation, 2013, p. 1173–1177.
[9] S. Jahn, R. Kahlenberg, C. Straube, M. Müller, “Empfehlungen zur Steigerung der Prozessstabilität beim Laserstrahlschmelzen” in Neue Entwicklungen in der Additiven Fertigung, G. Witt, A. Wegner, J. Sehrt, Springer Berlin Heidelberg, 2015, p. 127–141
[10] M. Zairi, Total quality management for engineers, Cambridge, England: Woodhead Pub
[11] C. Eschey, Maschinenspezifische Erhöhung der Prozessfähigkeit in der additiven Fertigung, Technical University Munich, 2013
[12] V. Seyda, Werkstoff- und Prozessverhalten von Metallpulvern in der laseradditiven Fertigung, Springer Berlin Heidelberg, 2018
[13] M. Kohlhuber, M. Kage, M. Karg, Additive Fertigung: Statement, German National Academy of Sciences Leopoldina; acatech – German National Academy for Technical Sciences, Union of the German Academies of Sciences, 2016
[14] G. Witt (Ed.), Additive Fertigung – Statusreport: 3-D-Druckverfahren sind Realität in der industriellen Fertigung, 2019
[15] VDI Verein Deutscher Ingenieure/German Association of Engineers, VDI 2406 part 6.1:2019, “Additive manufacturing processes – User safety on operating the manufacturing facilities – Laser beam melting of metallic parts”, 2019
[16] H. Groneberg, C. Schuh, R. Steinhilper, F. Döpper, “Implementation of Methods for the Optimization of Processes and Production Systems: Catching the Mood of Small and Medium-sized German Enterprises” in Advances in Production Research: Proceedings of the 8th Congress of the German Academic Association for Production Technology (WGP), Aachen, November 19-20, 2018, Cham, 2019, p. 237–246
[17] F. Bertagnolli, Lean Management, Wiesbaden: Springer, 2018
[18] C. Tuck, R. Hague, N. Burns, “Rapid manufacturing: impact on supply chain methodologies and practice”, IJSOM, p. 1, 2007, Art. no. 11459, doi: 10.1504/IJSOM.2007.011459
[19] C. Feldmann, A. Gorj, 3D-Druck und Lean Production, Springer Wiesbaden, 2017
[20] A. Chiarini, Lean Organization: from the Tools of the Toyota Production System to Lean Office, Springer Milan, 2013
[21] S. Sandrock, A. Peck, “Arbeits- und Gesundheitsschutz” in ifaa-Edition, 5S als Basis des kontinuierlichen Verbesserungsprozesses, Institut für Angewandte Arbeitswissenschaft, Springer Vieweg, 2016
[22] K. Erlach, Value Stream Design, Berlin, Heidelberg: Springer, 2013
[23] T. Richardson, Total quality management. Albany, N.Y.: Delmar Publishers, 1997
[24] D. H. Stamatis, TQM Engineering Handbook, Boca Raton: Chapman and Hall/CRC (Quality and Reliability Ser, v.Vol. 52), 1997
[25] T. Wohlers, R. I. Campbell, O. Diegel, R. Huff, J. Kowen, Wohlers report 2020: 3D printing and additive manufacturing state of the industry, Fort Collins: Wohlers Associates, 2020
[26] TRGS 504: “Activities with exposure to A and E dust”, transmitted to TRGS 900, 2016
[27] TRGS 900: “German Technical Rules for Hazardous Substances: Occupational exposure limits”, 2006
[28] TRGS 559: “German Technical Rules for Hazardous Substances: Mineral dust”, 2010
[29] DIN Deutsches Institut für Normung, DIN 481:1993, “Workplaces atmospheres; size fraction definitions for measurement of airborne particles”, Berlin, 1993
[30] TRGS 910, “German Technical Rules for Hazardous Substances: Risk-related concept of measures for activities with carcinogenic hazardous substances”, 2014
[31] C. Bay, A. Mahr, “User safety during laser beam melting of metal powders within the scope of VDI Guideline 3405” in Rapid.Tech + FabCon 3.D: International Hub for Additive Manufacturing: Exhibition + Conference + Networking ;Proceedings of the 16th Rapid.Tech Conference, Erfurt, Germany, 25–27 June 2019, M. Kynast, M. Eichmann and G. Witt, Munich: Hanser, 2019, p. 430–440, doi: 10.3139/9783446462441.030
[32] Federal Republic of Germany, “Act on the Implementation of Occupational Safety and Health Measures to Improve the Safety and Health of Employees at Work (Occupational Safety and Health Act): ArbSchG”, 1996
[33] Federal Republic of Germany, “Ordinance on Protection against Hazardous Substances (Hazardous Substances Ordinance): GefStoffV”, 2010
[34] DIN Deutsches Institut für Normung, DIN 52904:2020 (Draft), “Additive manufacturing – Process characteristics and performance – Practice for metal powder bed fusion process to meet critical applications (Draft). 2020
[35] DIN Deutsches Institut für Normung, DIN SPEC 17071 :2019, “Additive manufacturing – Requirements for quality-assured processes at additive manufacturing centres”, 2019
[36] C. Carlson, Effective FMEAs. Achieving Safe, Reliable, and Economical Products and Processes using Failure Mode and Effects Analysis, Hoboken: John Wiley & Sons, 2012
[37] VBG German Administrative professional association – statutory accident insurance, “Gib dem Staub keine Chance!: Zehn goldene Regeln zur Staubbekämpfung“, Hamburg, May 2018
[38] B. H. Walley, Production management handbook. 2. ed. Aldershot: Gower, 1986