Completed Major Projects

 

SFB 1120 - Precision Melt Engineering

Short description:

The joining and coating of metallic components by means of melting processes is a particular challenge, since the flow and solidification of the melt strongly influence the component geometry and surface.

Thermal effects such as heat transfer and conduction as well as microstructural changes in the base material and filler metal also influence the degree of component precision. By increasing the precision of these melting processes, expensive finishing processes can be reduced, which is an economic advantage especially for larger high-precision components.

New approaches and technologies are required to influence melt phase dynamics and solidification. The goals of the Collaborative Research Center 1120 (SFB 1120) are the comprehensive understanding of these processes using the approach of "Precision Melt Engineering" as well as its derived measures to meet the precision requirements of melt-based manufacturing processes such as casting, joining, separating, additive manufacturing and coating. 11 research institutes of the RWTH Aachen University are working together in 22 sub-projects on the common goals. The IOT is working on the three sub-projects A5, A10 and A12.

The subproject A5 aims to increase the precision of brazing and TLP bonding. In order to achieve a targeted reduction of brittle phases and to improve the mechanical properties, brazing alloys are optimized and brazing processes are developed by means of current-assisted process control.

In subproject A10 the entire process of plasma spraying, starting with the plasma generator up to the coating build up is simulated. In this context, disturbance factors are identified and potential strategies for compensation are developed.

The subproject A12 is concerned with the development of thermally sprayed coatings that can be used to selectively control the heat flow on surfaces. For this purpose, casting tools are coated in order to realize a highly dynamic tempering during the casting process.

Funding: German Research Foundation (DFG)
Porject number: SFB 1120
Duration: July 1, 2017 to June 30, 2022
 

SPP 2074 - Fluid-free lubrication systems under high mechanical load

Short description:

In the research program Fluid-free lubrication systems under high mechanical load - SPP 2074, the friction and wear mechanisms due to the formation of transfer layers in tribological systems are being studied when lubricating with solid lubricants. For this purpose, the first step is to determine the system-specific supply processes of the solid lubricant as a function of the operating conditions (including temperature, pressure, sliding speeds) in order to be able to determine the requirements for the availability of solid lubricant in the contact area to be lubricated. Depending on the operating conditions, the lubricant and the contact partners in the highly loaded contact, the transfer processes will be clarified on this basis. Here, a distinction can be made between physical and chemical transfer processes, which enable the most durable transfer possible. Physical adhesion mechanisms can occur through a mechanical "clamping" of solid lubricant components with the surface, chemical mechanisms can be based on physisorption and chemisorption. The understanding should subsequently be used to synthesis systems for the supply and transfer of solid lubricants in highly stressed contact conditions.

In the sub-project Fluid-free lubricated spur gears - tribological analysis and design, self-lubricating hard coatings are being developed for use on gears. More detailed information is available here.

Funding: German Research Foundation (DFG)
Porject number: SPP 2074 - 407712786
Duration: January 1, 2019 to December 31, 2021
 
 

High Power Pulsed Magnetron Sputtering (HPPMS) coating deposition and process understanding

Short description:

Project A1 is a subproject of the Transregional Collaborative Research Centre SFB-TR87 in its third funding phase. The project investigates basic mechanisms of the synthetic pathway for the production of hard coatings in high-performance plasmas. The validation and consistency of the methodology for the knowledge-based design of industry-relevant coating processes on complex substrates for a concrete stress collective will be completed in the third phase. One aim is to transfer the knowledge-based methodology for the process development of the multilayer Cr-Al-O-N coating concept to (Ti;V)-Al-O-N. During the validation, results from different models developed in the SFB are brought together. The results are transferred to low-temperature processes for plastic substrates. Another aim is to increase the adhesion between individual layers and to the substrate. Through research on the etching phase of the PVD process, A1 seeks to design plasma etching processes for steel and plastic substrates. The substrate temperature, which is crucial for adhesion, is measured online in the process phases with the new temperature sensor and the influence of residual stresses on adhesion is being investigated. Furthermore, the project determines theoretically ideal layer thicknesses and residual stresses that are implemented in A1 during coating production. The work will be extended by investigations of corrosive interactions, the influence on plastic degradation and adhesion wear. New evaluation methods for the interaction between polycarbonate melt and Cr-Al-O-N will be transferred to other plastics and coatings, and subsequently be validated. On the long run, the coating selection for extrusion can be predicted depending on the plastic, which is produced in knowledge-based plasma processes. Poster SFB-TR 87 A1

Funding: German Research Foundation (DFG)
Porject number: SFB-TR 87 A1 - DFG TRR 87/3
Duration: July 1, 2018 to June 30, 2022

 
 

Influence of plasma properties on coating properties in pulsed high-performance plasmas

Short description:

The 3rd funding phase of the subproject C6 in the transregional collaborative research center SFB-TR 87seeks to validate process diagnostics methods that were developed in the 2nd funding phase. This aim is reached by transferring results from the Cr-Al-O-N system to (Ti;V)-Al-O-N. This will prove that the process development can be significantly shortened by using plasma diagnostics. At the same time, the incorporation of nitrogen into the coating, which is relevant for the coating development, is analyzed. In addition, the focus of the project is on the transfer and validation of the developed plasma diagnostic methods to production-ready process diagnostics. For the first time, also the cleaning effect of plasma etching is investigated diagnostically in order to increase the adhesion to steel and plastic substrates. For this purpose, the quality and effectiveness of plasma etching is correlated with plasma parameters and the substrate temperature in order to obtain the best possible plasma cleaning near the maximum permitted temperatures of the substrates. A further goal is the iterative development and validation of artificial neural networks (ANN). Here, the relationships between process and plasma, plasma and coating, and coating and system are considered. Overall, C6 contributes important work to overcoming the empirical approach to coating development using high-performance plasmas. Poster SFB-TR 87 C6

Funding: German Research Foundation (DFG)
Porject number: SFB-TR 87 C6 – DFG TRR 87/3
Duration: July 1, 2018 to June 30, 2022

 
 

Excellence Cluster „Integrative Production Technology for High-Wage Countries“ - Project C3 „Multi-Technology Products“ – Test case „Optic“

Short description:

The aim of the research project was the development of a continuous process chain for the production of structured, optically functional plastic components. Laser technology was used to introduce structures in the micro- or nanometer range into the cavities of the injection molding tool. These were molded by brittle plastics, such as polycarbonate and polymethyl methacrylate, in the subsequent plastics processing process. By coating the laser-structured tool using the physical vapor deposition (PVD) process, it was possible to reduce wear and the adhesive force between the tool surface and the plastics. In addition, it was shown that laser structures can only be molded by modifying the surface with a suitable PVD coating. Without the additional coating, the structures break from the uncoated mold during demolding and, in contrast to the coated mold, the polymer sticks to the structures. The replication ratio could be improved by 20 to 30 % depending on the structure type. Poster EXC-128

In the transition phase, PVD sensor coatings are developed for temperature measurement. The focus is on metallic sensor layers, which are protected from wear by hard coatings, as well as on sensor coatings, which themselves consist of hard coatings. The sensor coatings are suitable for providing production data in real time. By combining them with a thermally sprayed heating conductor coating to create a sensor-actuator system, the coating systems can independently influence the temperature control of manufacturing processes. Poster EXC-128 transition phase

Funding: German Research Foundation (DFG)
Porject number: EXC-128
Duration:

November 1, 2012 to October 31, 2017

November 1, 2017 to December 31, 2018 (transition phase)

 
 

Influence of solid-liquid reactions in the brazing gap on joint properties and precision

Short description:

The aim of the project is to reduce the quantity of intermetallic compounds in the brazing seam and the effect of the heat treatment on the base material when joining hot work tool steels with a nickel based filler metal. Thus to improve the mechanical and thermal properties of the joint will be improved. In order to achieve this the grain growth will be reduced by an adapted temperature control and by electric current assisted brazing which results in accelerated and directed diffusion during brazing. Poster SFB 1120 – Teilprojekt A5

Funding: German Research Foundation (DFG)
Porject number: SFB 1120 – Project A5
Duration: July 1, 2018 to June 30, 2022

 
 

Development of simulative approaches for specific developement of the properties of plasma sprayed coatings

Short description:

Project A10 deals with the tailored development of plasma-sprayed heat insulation coatings by means of numerical prediction. During atmospheric plasma spraying, not only process parameters but also disturbances influence process characteristics. As a result, the processes that occur during the transition of the coating building particles from the solid into the (partly) liquid state and from the (partly) liquid state into the solid state are also influenced. The correlation between the process parameters and the coating properties were successful in the first phase of the project, both numerically and experimentally. The focus of the second phase of the project lies on the analysis of disturbance-dependent process changes by means of modeling and simulation. The aim of the second phase is the prediction of the coating properties while taking into account the disturbances that occur in the real processes. Poster SFB 1120 – Teilprojekt A10

Funding: German Research Foundation (DFG)
Project number: SFB 1120 – Teilprojekt A10
Duration: July 1, 2018 to June 30, 2022