scholarly journals Adhesion Studies during Generative Hybridization of Textile-Reinforced Thermoplastic Composites via Additive Manufacturing

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3888
Author(s):  
Johanna Maier ◽  
Christian Vogel ◽  
Tobias Lebelt ◽  
Vinzenz Geske ◽  
Thomas Behnisch ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Polyamide 6 ◽  
Thermoplastic Composites ◽  
Efficient Production ◽  
Angle Measurements ◽  
Small Series ◽  
Contact Angle Measurements ◽  
Static Tensile ◽  
Pre Treatment ◽  
Manufacturing Technologies

Generative hybridization enables the efficient production of lightweight structures by combining classic manufacturing processes with additive manufacturing technologies. This type of functionalization process allows components with high geometric complexity and high mechanical properties to be produced efficiently in small series without the need for additional molds. In this study, hybrid specimens were generated by additively depositing PA6 (polyamide 6) via fused layer modeling (FLM) onto continuous woven fiber GF/PA6 (glass fiber/polyamide 6) flat preforms. Specifically, the effects of surface pre-treatment and process-induced surface interactions were investigated using optical microscopy for contact angle measurements as well as laser profilometry and thermal analytics. The bonding characteristic at the interface was evaluated via quasi-static tensile pull-off tests. Results indicate that both the bond strength and corresponding failure type vary with pre-treatment settings and process parameters during generative hybridization. It is shown that both the base substrate temperature and the FLM nozzle distance have a significant influence on the adhesive tensile strength. In particular, it can be seen that surface activation by plasma can significantly improve the specific adhesion in generative hybridization.

The Effect of Hydrofluoric Acid Concentration in Sulfuric Acid-Based Desmutting Solution for Aluminium Alloys

2021 ◽  
Vol 1016 ◽  
pp. 934-939
Author(s):  
Tullio Monetta ◽  
Anna Carangelo ◽  
Francesco Bravaccino ◽  
Ciro Sinagra ◽  
Annalisa Acquesta
Keyword(s):  
Acid Concentration ◽  
Hydrofluoric Acid ◽  
Electrochemical Techniques ◽  
Optical Emission ◽  
Conversion Coating ◽  
Emission Spectrometry ◽  
Angle Measurements ◽  
Contact Angle Measurements ◽  
Natural Oxide ◽  
Pre Treatment

The natural oxide layer, which spontaneously covers the surface of aluminium and its alloys, is well adherent to the surface, but it does not show adequate corrosion resistance in many conditions. In order to improve the material anti-corrosion performance, it is necessary to replace the surface oxide by a conversion coating. The first step to do this is to prepare the alloy surface to subsequent treatments. The pre-treatment implemented before the conversion treatment is one of the main factors responsible for the performance of the conversion coating. It involves several phases, including desmutting that encompasses the part immersion in an acid or alkaline solution bath. In this work, the influence of hydrofluoric acid concentration in the desmutting bath's formulation was investigated. The samples surface were characterised by using electrochemical techniques, glow discharge optical emission spectrometry and contact angle measurements.

scholarly journals Multi-Criteria Comparative Analysis of the Use of Subtractive and Additive Technologies in the Manufacturing of Offshore Machinery Components

2020 ◽  
Vol 27 (3) ◽  
pp. 71-81
Author(s):  
Mariusz Deja ◽  
Mieczysław Stanisław Siemiątkowski ◽  
Dawid Zieliński
Keyword(s):  
Additive Manufacturing ◽  
Production Method ◽  
Industrial Applications ◽  
Lead Times ◽  
Efficient Production ◽  
Cnc Milling ◽  
Analytic Hierarchy ◽  
3D Printed ◽  
Offshore Industry ◽  
Manufacturing Technologies

AbstractThe dynamic development of additive manufacturing technologies, especially over the last few years, has increased the range of possible industrial applications of 3D printed elements. This is a consequence of the distinct advantages of additive techniques, which include the possibility of improving the mechanical strength of products and shortening lead times. Offshore industry is one of these promising areas for the application of additive manufacturing. This paper presents a decision support method for the manufacturing of offshore equipment components, and compares a standard subtractive method with an additive manufacturing approach. An analytic hierarchy process was applied to select the most effective and efficient production method, considering CNC milling and direct metal laser sintering. A final set of decision criteria that take into account the specifics of the offshore industry sector are provided.

scholarly journals An initiator- and catalyst-free hydrogel coating process for 3D printed medical-grade poly(ε-caprolactone)

2021 ◽  
Vol 17 ◽  
pp. 2095-2101
Author(s):  
Jochen Löblein ◽  
Thomas Lorson ◽  
Miriam Komma ◽  
Tobias Kielholz ◽  
Maike Windbergs ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Gain Control ◽  
Bulk Polymerization ◽  
Processing Methods ◽  
Hydrophilic Modification ◽  
Catalyst Free ◽  
Angle Measurements ◽  
Contact Angle Measurements ◽  
3D Printed ◽  
Medical Grade

Additive manufacturing or 3D printing as an umbrella term for various materials processing methods has distinct advantages over many other processing methods, including the ability to generate highly complex shapes and designs. However, the performance of any produced part not only depends on the material used and its shape, but is also critically dependent on its surface properties. Important features, such as wetting or fouling, critically depend mainly on the immediate surface energy. To gain control over the surface chemistry post-processing modifications are generally necessary, since it′s not a feature of additive manufacturing. Here, we report on the use of initiator and catalyst-free photografting and photopolymerization for the hydrophilic modification of microfiber scaffolds obtained from hydrophobic medical-grade poly(ε-caprolactone) via melt-electrowriting. Contact angle measurements and Raman spectroscopy confirms the formation of a more hydrophilic coating of poly(2-hydroxyethyl methacrylate). Apart from surface modification, we also observe bulk polymerization, which is expected for this method, and currently limits the controllability of this procedure.

scholarly journals An Overview on Personal Protective Equipment (PPE) Fabricated with Additive Manufacturing Technologies in the Era of COVID-19 Pandemic

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2703 ◽  
Author(s):  
Szilard Rendeki ◽  
Balint Nagy ◽  
Matyas Bene ◽  
Attila Pentek ◽  
Luca Toth ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Open Source ◽  
Personal Protective Equipment ◽  
Face Mask ◽  
Protective Equipment ◽  
Fused Filament Fabrication ◽  
Small Series ◽  
Source Models ◽  
3D Printed ◽  
Manufacturing Technologies

Different additive manufacturing technologies have proven effective and useful in remote medicine and emergency or disaster situations. The coronavirus disease 2019 (COVID-19) disease, caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) virus, has had a huge impact on our society, including in relation to the continuous supply of personal protective equipment (PPE). The aim of the study is to give a detailed overview of 3D-printed PPE devices and provide practical information regarding the manufacturing and further design process, as well as describing the potential risks of using them. Open-source models of a half-face mask, safety goggles, and a face-protecting shield are evaluated, considering production time, material usage, and cost. Estimations have been performed with fused filament fabrication (FFF) and selective laser sintering (SLS) technology, highlighting the material characteristics of polylactic acid (PLA), polyamide, and a two-compound silicone. Spectrophotometry measurements of transparent PMMA samples were performed to determine their functionality as goggles or face mask parts. All the tests were carried out before and after the tetra-acetyl-ethylene-diamine (TAED)-based disinfection process. The results show that the disinfection has no significant effect on the mechanical and structural stability of the used polymers; therefore, 3D-printed PPE is reusable. For each device, recommendations and possible means of development are explained. The files of the modified models are provided. SLS and FFF additive manufacturing technology can be useful tools in PPE development and small-series production, but open-source models must be used with special care.

scholarly journals Innovative Methodology for the Identification of the Most Suitable Additive Technology Based on Product Characteristics

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 409
Author(s):  
Antonio Del Prete ◽  
Teresa Primo
Keyword(s):  
Supply Chain ◽  
Additive Manufacturing ◽  
High Performance ◽  
Spare Parts ◽  
Design For Additive Manufacturing ◽  
Small Series ◽  
Cad Models ◽  
Definition Of ◽  
Manufacturing Technologies ◽  
Client Needs

This paper reports the study and development case of an innovative application of the Cloud Manufacturing paradigm. Based on the definition of an appropriate web-based application, the infrastructure is able to connect the possible client requests and the relative supply chain product/process development capabilities and then attempt to find the best available solutions. In particular, the main goal of the developed system, called AMSA (Additive Manufacturing Spare parts market Application), is the definition of a common platform to supply different kinds of services that have the following common reference points in the Additive Manufacturing Technologies (DFAM, Design For Additive Manufacturing): product development, prototypes, or small series production and reverse engineering activities to obtain Computer-Aided Design (CAD) models starting from a physical object. The definition of different kinds of services allows satisfying several client needs such as innovative product definition characterized by high performance in terms of stiffness/weight ratio, the possibility of manufacturing small series, such as in the motorsport field, and the possibility of defining CAD models for the obsolete parts for which the geometrical information is missed. The AMSA platform relies on the reconfigurable supply chain that is dynamic, and it depends on the client needs. For example, when the client requires the manufacture of a small series of a component, AMSA allows the technicians to choose the best solutions in terms of delivery time, price, and logistics. Therefore, the suppliers that contribute to the definition of the dynamic supply chain have an important role. For these reasons, the AMSA platform represents an important and innovative tool that is able to link the suppliers to the customers in the best manner in order to obtain services that are characterized by a high-performance level. Therefore, a provisional model has been implemented that allows filtering the technologies according to suitable performance indexes. A specific aspect for which AMSA can be considered unique is related with the given possibility to access Design for Additive Manufacturing Services through the Web in accordance with the possible additive manufacturing technologies.

Nanostructured Polymer Brushes With Reversibly Changing Properties

2002 ◽  
Vol 727 ◽  
Author(s):  
Denys Usov ◽  
Manfred Stamm ◽  
Sergiy Minko ◽  
Christian Froeck ◽  
Andreas Scholl ◽  
...  
Keyword(s):  
Polymer Brushes ◽  
Phase Segregation ◽  
Water Contact ◽  
Angle Measurements ◽  
Nanostructured Polymer ◽  
Contact Angle Measurements ◽  
Vertical Segregation ◽  
Oxygen Plasma Etching ◽  
Grafting From ◽  
Photoemission Electron

AbstractWe investigated the interplay between different mechanisms of the lateral and vertical segregation in the synthesized via “grafting from” approach symmetric A/B (where A and B are poly(styrene-co-2,3,4,5,6-pentafluorostyrene) and poly(methylmethacrylate), respectively) polymer brushes upon exposure to different solvents. We used X-ray photoemission electron spectroscopy and microscopy (X-PEEM), AFM, water contact angle measurements, and oxygen plasma etching to study morphology of the brushes. The ripple morphology after toluene (nonselective solvent) revealed elongated lamellar-like domains of A and B polymers alternating across the surface. The dimple-A morphology consisting of round clusters of the polymer A was observed after acetone (selective solvent for B). The top layer was enriched with the polymer B showing that the brush underwent both the lateral and vertical phase segregation. A qualitative agreement with predictions of SCF theory was found.

Wrinkling Poly(trimethylene 2,5-Furanoate) Free-standing Films: Nanostructure Formation and Physical Properties

2020 ◽  
Author(s):  
Michelina Soccio ◽  
Nadia Lotti ◽  
Andrea Munari ◽  
Esther Rebollar ◽  
Daniel E Martínez-Tong
Keyword(s):  
Irradiation Time ◽  
Polymer Surface ◽  
Laser Source ◽  
Free Standing ◽  
Force Microscopy ◽  
Nanostructure Formation ◽  
Physicochemical Changes ◽  
Angle Measurements ◽  
Atomic Force ◽  
Contact Angle Measurements

<p>Nanostructured wrinkles were developed on fully bio-based poly(trimethylene furanoate) (PTF) films by using the technique of Laser Induced Periodic Surface Structures (LIPSS). We investigated the effect of irradiation time on wrinkle formation using an UV pulsed laser source, at a fluence of 8 mJ/cm2. It was found that the pulse range between 600 and 4800 pulses allowed formation of periodic nanometric ripples. The nanostructured surface was studied using a combined macro- and nanoscale approach. We evaluated possible physicochemical changes taking place on the polymer surface after irradiation by infrared spectroscopy, contact angle measurements and atomic force microscopy. The macroscopic physicochemical properties of PTF showed almost no changes after nanostructure formation, differently from the results previously found for the terephthalic counterparts, as poly(ethyleneterephthalate), PET, and poly(trimethyleneterephthalate), PTT. The surface mechanical properties of the nanostructured PTF were found to be improved, as evidenced by nanomechanical force spectroscopy measurements. In particular, an increased Young’s modulus and higher stiffness for the nanostructured sample were measured. <br></p>

AM-Serienproduktion für die Automobilindustrie/AM series production for the automotive industry

2020 ◽  
Vol 110 (11-12) ◽  
pp. 752-757
Author(s):  
Lukas Weiser ◽  
Marco Batschkowski ◽  
Niclas Eschner ◽  
Benjamin Häfner ◽  
Ingo Neubauer ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Automotive Industry ◽  
Series Production ◽  
Production Scale ◽  
Additive Fertigung ◽  
Small Series ◽  
Start Up ◽  
3D Printed ◽  
Component Quality

Die additive Fertigung schafft neue Gestaltungsfreiheiten. Im Rahmen des Prototypenbaus und der Kleinserienproduktion kann das Verfahren des selektiven Laserschmelzens genutzt werden. Die Verwendung in der Serienproduktion ist bisher aufgrund unzureichender Bauteilqualität, langen Anlaufzeiten sowie mangelnder Automatisierung nicht im wirtschaftlichen Rahmen möglich. Das Projekt „ReAddi“ möchte eine erste prototypische Serienfertigung entwickeln, mit der additiv gefertigte Bauteile für die Automobilindustrie wirtschaftlich produziert werden können. Additive manufacturing (AM) offers new freedom of design. The selective laser-powderbed fusion (L-PBF) process can be used for prototyping and small series production. So far, it has not been economical to use it on a production scale due to insufficient component quality, long start-up times and a lack of automation. The project ReAddi aims to develop a first prototype series production to cost-effectively manufacture 3D-printed components for the automotive industry.

scholarly journals Additive Manufacturing-Based In Situ Consolidation of Continuous Carbon Fibre-Reinforced Polycarbonate

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2450
Author(s):  
Andreas Borowski ◽  
Christian Vogel ◽  
Thomas Behnisch ◽  
Vinzenz Geske ◽  
Maik Gude ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Carbon Fibre ◽  
Bending Test ◽  
Thermoplastic Composites ◽  
Experimental Investigations ◽  
Material Structure ◽  
Three Point Bending ◽  
Continuous Fibre ◽  
Local Material

Continuous carbon fibre-reinforced thermoplastic composites have convincing anisotropic properties, which can be used to strengthen structural components in a local, variable and efficient way. In this study, an additive manufacturing (AM) process is introduced to fabricate in situ consolidated continuous fibre-reinforced polycarbonate. Specimens with three different nozzle temperatures were in situ consolidated and tested in a three-point bending test. Computed tomography (CT) is used for a detailed analysis of the local material structure and resulting material porosity, thus the results can be put into context with process parameters. In addition, a highly curved test structure was fabricated that demonstrates the limits of the process and dependent fibre strand folding behaviours. These experimental investigations present the potential and the challenges of additive manufacturing-based in situ consolidated continuous fibre-reinforced polycarbonate.

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