The focus of the transfer pilot is the approach to develop and optimize a technology that enables conductive structures with a thickness of several 10µm to be additively deposited on a variety of plastics on the basis of plasma coating processes. It should also be possible to process plastic substrates that have been manufactured using additive manufacturing processes, such as selective laser sintering (SLS) or SLA. This will make it possible for the first time to economically manufacture individual power distributors in very small quantities. At the same time, the company is to be qualified to further develop such technologies independently and in a targeted manner in the future. Existing knowledge and expertise of Fraunhofer IEM in the field of systems engineering and spatial additive electronics (MID) will form the basis for the further development of the Plasmatreat product development. Existing SE approaches will be reflected and adapted to the needs and processes at Plasmatreat, taking into account the product and process technologies.

Initial situation

• Energy distribution, especially in cyber-physical systems, is an important key component for the functioning of these systems.

• The trend towards customized individual solutions and form-adaptive design (3D) increases the design effort. Although wired solutions are flexible, they are expensive to manufacture and assemble, especially for small batch sizes.

• 3D circuit carriers can also be produced cost-effectively and in small quantities, e.g. using additive processes. The proven MID (Mechatronic-Integrated-Device) technology can be used for this, but has certain limitations in terms of current carrying capacity. Due to the electroless metallization, layer thicknesses of conductive structures can only be produced economically up to approx. 16 micrometres. If higher conductor cross-sections are required, electroplating is possible. However, the effort required for contacting and implementation is very high and correspondingly expensive.

• The combination of plasma deposition and additively manufactured circuit carriers offers an interesting approach for the flexible design of 3D high-current-capable power distribution systems, such as those required in the automotive sector (fuse boxes, etc.).

• Plasma deposition can be used to quickly deposit large conductor cross-sections on plastics. However, these have too low conductivity. This can be significantly reduced by chemical refinement, enabling the creation of low-resistance connections.



Procedure

• Analysis of the existing plasma separation process

• Identification of the technological limits of this process

• Development of methods to increase conductivity and selectivity

• Design of specific test and test specimens

• Production of test and test specimens

• Validation of the process using various test and test specimens



Results

• It has been shown that the combination of plasma deposition and chemical refinement enables the realization of high-current-capable cables.

• Chemical refinement has increased conductivity by up to a factor of 10 compared to the previous method.

• The combination of plasma deposition and additive processes opens up a wide range of applications due to the shape design, especially for individual solutions for small quantities. This means that the established and tool-intensive process of 3D punching grids for current distribution can be dispensed with. This increases flexibility in production and reduces the time-to-market period, as no tools are produced and required.

• As this is a very new and innovative technology, validations still need to be carried out in terms of reliability, which are particularly necessary in the automotive sector.