Micro Dosing

Dosage of gases and liquids to the nearest nanoliter is a central and longstanding area of expertise at Fraunhofer EMFT, covering a broad range of applications – from medical technology through to industrial applications and consumer electronics.

Micropumps

Piezo-electrically powered micropumps are at the heart of micro dosing systems. The Fraunhofer EMFT team possesses extensive expertise and practical experience in the design of micropumps. On this basis, it is possible to adapt the technological requirements in terms of dosage precision, counterpressure resistance, size, energy consumption, particle resistance, bubble tolerance and free-flow protection to the application in question.

Fraunhofer EMFT has designed a portfolio of silicon and stainless steel micropumps for various areas of use. One main focus of the R&D activities in the area of silicon micropumps is further miniaturization. The aim here is to significantly reduce production costs, thereby facilitating access to the mass markets. The smallest silicon membrane pump currently available in the world, sized 3.5 x 3.5 x 0.6 mm³ , was developed at Fraunhofer EMFT. A key focus just now in the area of stainless steel micropumps is designing the micro dosing components. Here Fraunhofer EMFT cooperates closely with industry partners: the aim is for the latter to able to manufacture the components themselves in high volumes subsequent to the respective technology transfer.

Besides micropumpsthe EMFT competence field micro dosing consists of the sub-topics micro dosing components and microfluidics on foil substrates.

Micro dosing components

In addition to micropumps, Fraunhofer EMFT develops other micro dosing components that are indispensable for precise and reliable dosage.

• Electronic activation systems for micropumps: Electronic activation systems for micropumps are designed and developed for specific applications taking into account the various requirements. Factors such as the noise of the piezo actuator, piezo fatigue, piezo breakage and energy consumption can all be significant here.
• Bubble separators: This separating element is especially required for applications in medical technology, e.g. medical dosing systems, in order to reliably remove bubbles from the fluid path.
• Safety valve: A safety valve is a passive component which is normally closed and self-blocking. It prevents so-called free-flow, as can occur in membrane pumps with passive one-way valves, for example.
• Normally closed micro valve: Self-blocking, active normally closed micro valve.
• Integrated micropump driver: Fully integrated circuit concepts allow highly efficient control of the micropump at minimum size. The control signals can be optimized for the selected micropump and the customer-specific application case in terms of voltage span, polarity and edge steepness. 

In addition to its development expertise in the area of micro dosing components, the Fraunhofer EMFT team also has extensive system competence. Micro dosing as cross-cutting technology requires wide-ranging knowledge of such areas as fluid mechanics, elastomechanics, surface physics, chemistry and phase transformation. Understanding the causal relations between these various factors is essential in order to enable smooth interplay of all components in a micro dosing system.

In order to optimize the performance and reliability of their micro dosing systems even further, researchers work continuously on new solutions – for example in the management of bubbles, particles and back pressure, dosage monitoring of very small quantities and also chemical resilience.

Microfluidics on foil substrates

In some areas of application such as medical technology and consumer electronics, disposable microfluidic systems open up attractive new market opportunities. Here, foil electronics offers interesting potential for the low-cost manufacture of disposable microfluidic systems in large quantities. At Fraunhofer EMFT, disposable dosage dispensers for aerosol and microjetting are printed on foil using the roll-to-roll method, for example (printed dispensers). These are suitable for applications such as fragrance and interior insecticide dosage.