Process Optimisation

Sustainable heating processes are a focus of research and development activities at Fraunhofer-Center HTL. This includes issues such as the conversion of thermal processes to CO2-neutral operation, for example by using green hydrogen as a heat source, or the general switch from gas firing to electric heating. In addition to these approaches, which are usually accompanied by investment requirements for the user, the HTL also offers a systematic methodology for optimising thermoprocesses that does not require any structural changes to existing thermoprocess plants. In a material-centred approach, the behaviour of the material to be heated in the thermoprocess is first precisely measured. With the help of digital process models or digital furnace twins, the optimal process control is then determined. The efficiency gain is achieved both by minimising the process time and by optimising the product quality (minimising the reject rate). Simply by applying the optimised oven parameters, the cost and carbon footprint of each product is reduced by at least 10-20%, often more.

The complete methodology starts with a green body analysis, as defects from the moulding process usually do not heal in the thermoprocess and every unnecessarily fired component that subsequently becomes scrap is a waste of energy and money. Subsequently, the product-specific material changes during the following process steps of drying, debinding and sintering are characterised by in-situ measurements. Based on the measurement results, the processes for the concrete product geometry are simulated on the computer and thus the optimal process parameters are determined and validated. The process can also be optimised in an analogous way for products that are manufactured by melt infiltration instead of sintering.

Here you will find a selection of our research projects:

  • BaMOX Development of a basalt fibre-reinforced mixed oxide ceramic using the example of a hand casting crucible
  • NeMaKo Development of novel magnesium oxide composites
  • Screws in zirconium oxide Screw made of zirconium oxide for use under high mechanical, corrosive and thermal loads
  • CMC-BHM Development of short-fibre reinforced composites for use as kiln furniture
  • Enertherm Development of lightweight materials for high-temperature use
  • Enertherm Energy efficiency in continuous heat treatment plants: Design of roller kilns
  • DiMaWert Sub-project: DigiTherm - Life Cycle Assessment

These publications might also interest you:

Further information

Green Body Analysis

To achieve the aspired product quality via heat treatment, green bodies must feature adequate properties, too. The following aspects generally apply: The green bodies must be as homogeneous as possible on the macro-, meso- and micro-scale.


The debinding of green bodies is measured in situ with the ThermoOptical measurement systems (TOM) as well as with the thermal analysis method at the Fraunhofer-Center HTL and subsequently optimized. The optimization is undertaken for all types of green bodies regardless of the component size and geometry, the inorganic components (metals or ceramics) and the type of organic binder and/or the binder content.


Subsequent to the forming, drying is usually necessary, before the shaped bodies can be debindered in the furnace. The moisture content must thereby be reduced from 10 to 50% by volume to approximately 1% by volume.

Melt Infiltration

As an alternative to sintering, the melt infiltration method can be used to create a dense component from a porous molding body. The prerequisite is that the base material consists of a porous body having a higher melting point than the infiltrating material. Furthermore, the melt must wet the base material.



The sintering of green bodies is measured in situ with high reproducibility using the ThermoOptical measurement systems (TOM) at the Fraunhofer-Center HTL. The obtained data are then used for process optimization. The quality of the sintering process depends strongly on the atmosphere in the furnace.

Other application and product areas

Aeronautics and Aerospace

Energy Technology

Ceramic Products