Research projects – Institute of Micro Production Technology

MicroMill

Micro-milling is increasingly finding applications due to advancing developments in micro-tool manufacturing. Structuring a workpiece with geometries on a micrometer scale is possible thanks to tools with ever smaller diameters. However, these are costly to manufacture. Each milling tool must be made from solid material and undergo time-intensive grinding. This is then reflected in the price of the tools. The micro milling tools to be produced in this project are to be manufactured from silicon carbide in a batch production process, so that several hundred milling heads can be produced per time. A dry etching process will be used to pattern the milling heads, and its process parameters must be evaluated for the most anisotropic etching possible at high etch rates. Since the milling tool is produced in two parts and consists of a milling head and tool shank, an ideal joining method is sought with which both parts can be reliably joined. For this purpose, different adhesives and chemical as well as mechanical surface treatments are tested on the surfaces to be joined. The resulting adhesive strength of the two tool parts will be investigated. Furthermore, a very precise assembly technique must be developed so that the milling head can be centered on the tool shank. Otherwise, among other things, inaccuracies in the shape of the workpieces may occur. The manufacturing process will then be industrialized with the project partner Reißfelder Profilschleifen GmbH and the application limits of the milling tools will be tested on various materials with industrial benefits, such as copper or steel. The end result should be small micro milling tools made of silicon carbide, which can be used for machining in various areas, such as medical technology, and can be produced on an industrial scale.

Year: 2021

Funding: Förderprogramm ZIM (Zentrales Innovationsprogramm Mittelstand) des Bundesministeriums für Wirtschaft und Energie (BMWi)

Duration: 2021-2023

AiF

The component quality of deep-drawn parts is subject to certain process fluctuations in series production due to constantly changing input variables. In this context, comprehensive process monitoring could ensure consistent drawn part quality and reduce the number of rejects. Within the scope of the project, the material flow of the deep-drawing sheet is to be recorded and evaluated with the aid of a sensor unit specially developed for this purpose at the IMPT. The project includes, among other things, the simulative design and thin-film production of an inductive sensor as well as the construction of a control loop in an industrial environment.

Year: 2019

Funding: Forschungsvereinigung für Stahlanwendungen (FOSTA)

Duration: 2019 - 2024

SFB 1368 C03 – Investigation of tribological systems for tool coatings in an inert atmosphere

In the Collaborative Research Center 1368 "Oxygen-free production", processes and mechanisms in manufacturing technology processes are investigated that are carried out in an oxygen-free atmosphere. In subproject C03, the IMPT is investigating the influence of the atmosphere on tribological systems for the subsequent development of tool coatings in an inert atmosphere. Important aspects include the identification and quantification of fundamental relationships of wear processes in silane-doped atmospheres, diffusion and adhesion effects and the investigation of possible novel alloy formations at the interfaces.

Year: 2020

Funding: DFG

Duration: 2020 - 2023

Fundamental investigation of the mechanisms of ultrasonic wedge-wedge bonding using varying topographies

Ultrasonic wire bonding has been used in microelectronics for more than half a century. However, the underlying mechanisms are not fully understood, which prevents further improvement of this technique. This project’s aim is to find unknown mechanisms and investigate their influence on the bonding process.

Year: 2017

Funding: Deutsche Forschungsgemeinschaft (DFG)

Duration: 2017 - 2019

SFB 653 T14 - Development and manufacturing of direct-deposited sensors on bottom hole assemblies

Within the Collaborative Research Center 653 "Intelligent Components in the Life Cycle" this transfer project has been developed in cooperation with an industrial partner. The aim of the project is the thin-film production of sensitive strain gauges that can detect the mechanical stresses of drilling bottom hole assemblies and withstand the harsh conditions underground. A novel, patent-pending coating system is used for this purpose, which allows sensors to be deposited directly onto component surfaces of any size. In addition to the development of temperature-compensated strain gages, the project also addresses the aspect of deposition on curved surfaces.

Year: 2018

Funding: DFG

Duration: 2018 - 2021

Force-sensitive guidance systems based on direct-deposited component-specific sensor technologies

In the machine tools of modern production technology, forces represent an important source of information for process controlling and condition monitoring. Measuring of the occurring process forces allows the detection of tool breakages and process errors. Additionally, the tool displacement and the tool wear can be estimated. With the example of a portal milling machine, new types of direct-deposited strain gauges are used in this project due to the high demands on the necessary sensors. They are produced directly on the guide carriages, which are used to move the milling head in all three spatial directions on linear profile rails. The result are particularly thin and sensitive sensors that can record the forces and torques with high precision. Methods for simulating the optimum sensor positions and sensor data fusion exploit the full potential of the technology.

Year: 2021

Funding: DFG

Duration: 2021 - 2024

Batch manufactured flexible micro-grinding tools for finishing metallic surfaces

Grinding tools manufactured by thin-film technology show great potential for the production of high surface finishes and for the manufacture of microstructures. The aim of this project is to investigate and model the relationships between the manufacturing process and the application behavior of the novel, compliant micro-grinding tools. In this context, the technological and economic potential of the lithographically produced tools is also to be identified, especially with regard to batch production. In order to ensure workpiece machining and to demonstrate the tool potential, basic tools with defined parameters will be manufactured according to the requirement profiles of ultra-precision and micro-machining. The characterization of the application behavior of the micro-grinding tools represents a further objective of this project. The main focus is on analyzing the relationships between the abrasive and support layers as well as the application behavior and the manufacturing result. Based on the results of the investigation, an empirical wear model will be developed. Furthermore, the project aims at the development of an electrochemical cell for the oxidation of copper surfaces. This process is intended to control the mechanical properties of the surface in a targeted manner in order to counteract the ductile behavior of the copper during ultraprecision machining and micromachining. This can enable better structuring and higher surface finishes. The cell will also be integrated into a 5-axis CNC milling machine to seamlessly integrate the electrochemical machining of the workpiece into metal-cutting process flows. The oxide behavior of the copper workpieces will also be modeled based on the results. Furthermore, a validation of the models and the tool production will be carried out during the project. Adapted workpieces will then be manufactured and tested on the basis of defined application scenarios.

Year: 2019

Funding: Deutsche Forschungsgemeinschaft (DFG)

Duration: 2019 - 2022

Ultrasonic silver sintering

Today's demands on power electronics have risen significantly, especially due to e-mobility, making the connection properties of proven methods such as soldering or adhesive bonding no longer adequate for future requirements. Silver compound sintering is gaining in importance due to its superior electrical and thermal properties. However, the long process times and high temperatures and pressures prevent the extensive use of this joining method. This is where the DFG-funded project sets in and researches the optimisation of these process parameters by using ultrasound. With the help of suitable alloy partners, low-melting sintering pastes are also being produced, with which the process of Ultrasonic Transient Liquid Phase Sintering (ULTPS) will be established.

Year: 2021

Funding: DFG

Duration: 2021 - 2023