Hochtemperaturofen in Betrieb
|Period:||2011-04-01 to 2012-06-30|
|Funder:||Federal Ministry of Economics and Technology via ZIM|
|Project Manager:||Dr. Mario Rudolphi|
|Research Group:||High Temperature Materials|
Thermoforming is a method used to create various plastic shapes by heating a plastic sheet to a pliable temperature and pressing it into a mould of the desired shape. Removal of the sheet from the mould and trimming the plastic results in the final product. Vacuum forming is one common thermoforming technique where the pliable plastic sheet is sucked into the mould by applying a vacuum between the mould and the plastic sheet. Typically, vacuum forming moulds are made from an aluminium block with chip machining tools, which limits the amount of detail that can be achieved. Furthermore, suction holes have to be drilled into the mould to be able to apply the vacuum, which creates unwanted artefacts.
A novel layered slurry ceramics material which was developed by our project partner Kunstguss-Team Grundhöfer GmbH, Niedernberg, is presented as a promising alternative, allowing very fine details to be formed and vacuum application through the porous ceramic without the need for suction holes.
The aim of this project is the production of a functioning prototype mould that meets the requirements of the thermoforming industry. Consequently, a number of properties have to be tailored to the specific needs. The gas permeability needs to be high enough to evacuate the volume between mould and plastic sheet in a sufficiently short period of time and the mechanical stability of the mould has to be high enough to withstand the applied pressure during several thermoforming cycles. These properties can be adjusted by changing the composition of the slurry ceramics components and/or the sintering parameters. Since higher porosity leads to lower mechanical stability and vice versa, an optimum compromise has to be found. Therefore, a variety of experimental investigations such as porosimetry and gas permeability measurement, dilatometry, microstructural investigation and mechanical 4-point bend testing will be carried out to investigate the influence of slurry ceramic composition and sintering parameters on the gas permeability and mechanical stability.back