Additive manufacturing (AM) enables a new manufacturing paradigm, such as the rapid, distributive manufacture of complex objects. Additionally, it has the potential to reduce waste and to manufacture individual products anywhere in the world, and to customize each of them. The DIMAP project focuses on the development of novel ink materials for 3D multi-material printing by PolyJet technology. We will advance the state-of-the art of AM through modifications of their fundamental material properties by mainly using nanoscale material enhanced inks. This widens the range of current available AM materials and implements functionalities in final objects. Applications will not be limited to rapid prototyping but can be used directly in production processes. DIMAP shows this transition in two selected application fields: the production of robotic arms/joints and customized luminaires. In order to cope with these new material classes the existing PolyJet technology is further developed and improved. DIMAP targets at the following objectives:
- additive manufactured joints, additive manufactured luminaires,
- ceramic enhanced (CE) materials,
- electrically conducting (EC) materials,
- light-weight polymeric (LWP) materials,
- high-strength polymeric (HSP) materials,
- novel multi-material 3D-printer and
- safe by design.
With the development of novel ink materials based on nanotechnology improvement of the mechanical properties, the electrical conductivity and the weightiness are achieved. Based on the voxel printing by PolyJet these new materials lead to a huge broadening of the range of digital material combinations. Safe by design approaches include work place safety, risk assessment, collaboration with EU safety cluster and life cycle assessment. An established roadmap at the end of project enables the identification of future development needs in related fields order to allow Europe also in the future to compete at the forefront of the AM revolution. With the strong and good collaboration between the partners, their tremendous effort, joined experimental trials in technical workshops we managed to address and fulfill every objective.
Work performed
The first focus at the project start was on defining the design specifications and material requirements for the envisaged demonstrators (additive manufactured robotic joints and luminaires). This was used as basis for establishing the requirements and initial formulations of the novel ink systems and the printing process. During the second half of the project, all directions were pointing at integration and demonstration. Inks and processes were optimized, their interplay to each other investigated and final demonstrators designed and printed. In terms of CE inks different types of ceramic nanoparticles have been synthesized with different particle sizes. Dispersed in UV-curable monomer matrixes, first CE inks were obtained, together with jetting trials, curing strategy and mechanical testing of printed objects. Updated ink formulation with 50% ceramic loading, consequent jetting and curing trials and characterization led to the final semi-printable material showing thermal conductivity up to 2 W/m.K (at 25°C), a Young’s modulus of 1200 MPa and tensile strength of 22 MPa. In terms of EC ink, the set goal in terms of metal content, viscosity, jetting, curing and sintering parameters, shelf life and upscale ability was achieved. The final ink is jetable in several industrial print heads (Ricoh Gen3 E3, E1, Gen4l, KM512), at a frequency of up to 38 kHz. Via subsequent UV curing and NIR treatment within the prototype printer, resistivity of <10 μΩcm was shown, desirable for the DIMAP demonstrators. The HSP based ink development proceeded fast leading to a jetable ink with 80 w% precursor material. A comprehensive study regarding the curing behavior of selected precursors was performed together with jetting, curing and printing experiments and mechanical testing of printed objects. Hence, it was possible to print for the first time thermally stable PI objects by using the PolyJet technology. LWP materials were obtained by using ink systems that are foamable after printing. A proof of concept was obtained for either utilizing core-shell particles and generating open cell foams. The latter approach was favorable, resulting in a long-term stable ink, showing good jet- and printability. Foaming of printed test structures was demonstrated showing the capability of the approach. High strength polymeric and electrically conductive inks entered first a maturity level for investigating their interplay, yielding in functional printed parts of the demonstrators. CE and LWP materials needed a redo and therefore caused a delay in development. However, all 4 materials were shown to be printable in DIMAP prototype printers. Three development versions of the DIMAP prototype printer were constructed, acting as the focal point in Germany, Austria and Israel in the final development phase of DIMAP. Simulation tools and thermography methods supported the integration process for demonstrators. On subsequent designing, based on many iteration steps, we were able show the first PolyJet printed pneumatic robotic arm and printed customized luminaire.
Physiochemical properties of manufactured nanomaterials and exposure hotspots were identified with respect to nano-safety. A respective SDS template was created for use by the project partners. No significant release of nanomaterials were detected. Furthermore, DIMAP is partner with the Nanosafety cluster.
IMPACT
Almost unlimited customization, increasing printing speed and growing accuracy make AM production an attractive alternative to conventional mass production, enabling new manufacturing possibilities in Europe. Consumers now expect a seamless flow between their online and offline activities, forcing companies to quickly adapt their strategy to reflect online-driven consumer behavior or risk obsolescence. Consumers are also suffering from "search fatigue." Engaging customization experiences will add value to mainstream shopping sites because they offer a new level of creative interaction. The business models, new customization insights and multi-material technologies developed within DIMAP will enable SMEs as well as larger companies to offer unique custom products for high-impact electronic markets. As most products are based on more than one material, and since today this "multi-material" need is achieved by assembly, the new inks combined with the inkjet multi-material capabilities open a very large market for both functional prototypes and end used parts. DIMAP was and is contributing to European innovation capacity on the one hand with 4 patents, training of 5 PhD and several Diploma students in total, 8 scientific paper during project implementation and more to follow, protection of intellectual property, on the other hand by strengthening the European competitiveness with the development of design-driven & user orientated 3D printed functional multi-materials goods. In addition the printed demonstrators were and will be displayed at fairs to show the capability of the new materials and PolyJetTM printing.
Final results were summarize in the following broschure.
