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Plastic droplet welding: bond strength between plastic freeforming structures and continuous fiber-reinforced thermoplastic composites

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Plastic freeforming (PF) is an additive-manufacturing process for producing three-dimensional plastic parts based on 3D CAD data by applying plastic droplets in layers. This process is used to produce customer-specific and complex geometries (prototypes and small series) on organic sheets. A comparable serial process is the injection of a second component onto organic sheets by injection molding. A sufficient bond between the PF structure and the organic sheets is of particular importance for each application. If this is not guaranteed, the composite system cannot withstand the mechanical load and fails. The force exerted on the system can no longer be transmitted between the PF structure and the organic sheet. The organic sheet is made of glass fiber-reinforced polypropylene (PP). The connection between the organic sheet and the PF structure is achieved by welding the molten polymer droplets and the surface of the organic sheet. The PF structures are made of PP to ensure sufficient compatibility with regard to the weldability of the components. The processing of PP in the PF process is a challenge because PP is a semi-crystalline material. The shrinkage of semi-crystalline materials is significantly higher compared to amorphous materials. Due to the layered structure of the components, the shrinkage of the individual layers results in undesired warpage. The adhesive strength between the organic sheet and the PF structure is investigated by determining the bending strength in the 3-point bending test. The investigations include an optimization of the process parameters to maximize the adhesive strength. The experimental investigations show that an increase of the nozzle and build chamber temperature leads to a higher adhesive strength. In further investigations, the temperature of the nozzle shows no significant influence on the surface temperature despite the expected heat radiation. The surface temperature is almost only dependent on the temperature of the build chamber.

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  1. Potente H (2004) Fügen von Kunststoffen. Carl Hanser Verlag, München

    Google Scholar 

  2. Ehrenstein GW (2004) Handbuch Kunststoffverbindungstechnik. Carl Hanser Verlag, München

    Google Scholar 

  3. Bonten C (1999) Contribution to an explanation of the acting seams out of semi-crystalline thermoplastics. Shaker Verlag

  4. Keßling O. AKF - Neues industrielles additives Verfahren, RTejournal - Forum für Rapid Technologie, vol. 2015, accessible online:, retrieved on 08.02.2017

  5. Gibson I, Rosen D, Stucker B (2015) Additive manufacturing technologies, 2nd edn

    Book  Google Scholar 

  6. Duffner E (2016) Industrielle additive Fertigung funktionsfähiger Kunststoffteile. Leightweight Des 2

  7. Neff M, Keßling O (2014) Geschichtete Funktionsteile im industriellen Maßstab. Hanser-Verlag, München, p 64ff

    Google Scholar 

  8. ShimaSeiki, Online-Reference:, retrieved on 05.12.2018

  9. Stoll, Online-Reference:, retrieved on 05.12.2018

  10. Homepage Nike,, retrieved on 05.12.2018

  11. Haupt M, Lin H, Cherif C, Krzywinski S (2016) Weft-knitted preforms adapted for crash- and 3D-applications, 15th AUTEX World Textile Conference 2015. Bucharest (Romania), June 10-12, 2015

  12. Cherif C (2016) Textile materials for lightweight constructions. Springer, Heidelberg

    Book  Google Scholar 

  13. Schulz C (2013) Entwicklung einer Technologie für die Herstellung textiler Halbzeuge für thermoplastische Verbundwerkstoffe auf Basis der Mehrlagenflachstricktechnik, PhD Thesis, Technische Universität Dresden

Download references

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Correspondence to André Hirsch.

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Recommended for publication by Commission XVI - Polymer Joining and Adhesive Technology

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Moritzer, E., Hirsch, A., Heim, HP. et al. Plastic droplet welding: bond strength between plastic freeforming structures and continuous fiber-reinforced thermoplastic composites. Weld World 63, 867–873 (2019).

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