The aim of the research project is to develop a profound understanding of the processes involved in the creation, characterization and evaluation of galvanically reinforced circuit diagrams on three-dimensional thermoplastic components.
The focus is on three aspects:
- Determination of the maximum transmittable current, taking into account the substrate material and the achievable effective cross-sectional areas of the conductors.
- Proof of the fulfillment of automotive standard conditions of galvanically reinforced circuit diagrams, e.g. temperature shock test.
- The use of high-performance reactors for galvanic reinforcement enables layer structures with very high deposition rates and is easier to process. The technology appears to be much cheaper than electroless metallization.
Source: FAPS, FAU
The application-oriented, efficient network of services is a key component for the construction of mechatronic systems. It determines the function, the reliability and contributes significantly to the manufacturing costs. Characteristic for the design of electrical circuits is the current-carrying capacity of the conductive media, which depends on the place of operation, the installation situation, the heat exchange, the cross-section, the specific resistance and the timing of the current supply. Electrical interconnections from 3D-MID technology, which were produced using known structuring and metallization processes, are limited mainly because of the metal layer thicknesses of <50μm for the transmission of currents up to approx. 10A. By means of galvanic reinforcement, for example from LDS circuit diagrams in high-performance reactors, the layer thickness can be increased to well over 50 μm in approx. 30 minutes and thus an enlargement of the conductor track cross-section (theoretically up to 500 μm) can be achieved. In comparison to this, a process time of approx. 240 min is required for a layer structure of 20 μm in the electroless metallization. In the electrolytic reinforcement, the conductive circuit diagram on the component serves as the cathode, which is why a common area for contacting must be taken into account when designing the circuit diagram. The process parameters such as the chemical bath composition, bath temperature, current density, arrangement of the anode, flow to the component and the process time play an essential role for a homogeneous layer thickness distribution for surfaces, edges and undercuts and for the layer quality. The use of galvanic reinforcement in 3D-MID technology, however, requires basic knowledge such as process parameters, quality control and characteristics of the layers produced. In the proposed project, previously unexplored knowledge and methods along the value chain of 3D-MID components with integrated networking of higher currents are to be systematically developed. To be mentioned here are selection criteria for substrate materials, structure and composition of the metal layers, rules for the construction of the circuit diagrams with contact point, handling of the components, process control, characteristics of the generated metal structures such as ductility, adhesion and electrical conductivity as well as the determination of measurement methods for ensuring the quality parameters . The goal is to achieve a homogeneous maximum layer height of the conductor tracks with maximum electrical conductivity, ductility and adhesion within the shortest possible process time. The project starts with the gathering of specialist know-how from semi-additive circuit board production and electroplating of technical products such as gravure rollers, chrome-plated decorative parts, fittings or tools in which thicker layers are electroplated. Then, together with the partners from the PA, a requirement profile with target parameters is to be defined. In the next step, a suitable substrate material must be selected from the research results and analyzes. A test structure is to be developed for the test body, on the basis of which later tests on the characteristics can be carried out. The galvanic amplification should be carried out in the laboratory and preferably by experts with the aim of keeping the process time as short as possible. The layers are characterized in the analysis of the FAPS. After evaluating the results, rules for the design and construction of galvanically reinforced 3D-MID components are to be extracted. To illustrate the results, a demonstrator is to be produced from the on-board network of a car.
Benefits and economic importance for SMEs
The automotive industry and mechanical engineering are the main pillars of the manufacturing industry in Germany with a share of 38.8% of gross value added in 2018 (source: BMWI). In order to meet the challenges of sustainability, energy efficiency and digitization, companies have to become more and more flexible and adaptable. The 3D-MID technology per se offers a high solution potential due to the unlimited freedom of design. The HAKa3D project can convince the involved project partners of the efficiency, reliability and economy of the technology. During the processing, employees of the companies are instructed in the technology and can contribute the know-how directly or into future product and process developments. The project increases the competence and networking of the partners and thus the competitiveness. Components for highly piloted and electrified vehicles in the areas of propulsion, safety, assistance and infotainment systems as well as components for the control cabinet, transfer systems, connecting elements for batteries as well as handling and assembly systems are seen as products.