Close Contour Tool Optimization

In the German industry, almost two thirds of the final energy used consists of process heat - i.e. heat mostly at temperatures above 100 °C - a large part of it is used for the temperature control of tools for thermal shaping (remodelling). In many cases, tools with a large "thermal mass" must be heated and cooled cyclically with enormous energy input.

The principle of close contour tool temperature control reduces the thermally cycled tool mass to the contact area with the original or formed workpiece. In order to achieve this, heating elements and/or temperature control channels are required in this area. This allows

• a significant saving of heat when heating up the mould,
• a significant reduction in cycle times and thus a reduction in costs and
• the optimization of the temperature field on the workpiece surface (variothermal tempering) for a maximum of production quality.

In this context, we offer you

• the energetic analysis of temperature control processes or the development of innovative temperature control concepts,
• the performance of thermo-technical simulations for process optimization and process design,
• the strong combination of materials science and production engineering know-how.  

The close contour or variothermal temperature control of tools for thermal shaping, e.g. in injection moulding or foaming processes, initially requires a detailed thermal and fluidic design. For this purpose, the business unit has its own calculation algorithms as well as commercial software (COMSOL Multiphysics®) on hand.

For the selection of suitable materials, the design of temperature control channels with single-phase or two-phase flow or the optimization of the position of heating elements, material and transport quantities are required which can be determined in our thermo-technical laboratory. These include

• the thermal conductivity and heat capacity of materials,
• heat transfer coefficients for channel flow, flow through porous structures or evaporation,
• pressure loss coefficients in channel flows or flow through cellular materials.

The calculation of temporally and locally variable 3D temperature fields forms the basis for an optimal tool design.

Innovative and energy-efficient mould temperature control concepts can only be implemented with appropriate materials and manufacturing processes. Fraunhofer IFAM Dresden offers a wide range of expertise from one hand. These include for example

• cellular metallic materials for reducing the thermal mass of tools with optimum temperature control and strength (e.g. hollow sphere, fibre or metal foam structures),
• additive manufacturing processes for cost-effective production of individually contourable tool structures such as electron beam melting (EBM) or metallic 3D screen printing.

While EBM can be used to produce entire tools or parts of them, screen printing is to be understood as a process for the production of selected special parts, e.g. to avoid hotspots.