Acrolab was approached by a client to develop a fast heating & fast cooling composite mold for out-of-autoclave composite curing. The technological objective of this study was to develop a vapour chamber mold structure of complex shape used in aerospace and automotive composite part production to apply heat energy to the curing of the composite part and then remove heat from it rapidly, uniformly and isothermally.
Vapour chambers are based on the same principles as ISOBAR® Heat Pipes.
Creating a Mold Base With Uniform Temperature Distribution Would be Very Beneficial for Composite Part Production
This mold could be heated up to the pre-determined temperature for faster curing and the cooled down rapidly to the required temperature and thereby quicken the production cycle.
Using this method with the relevant vapor chamber mold, the cycle time could be reduced and the quality of the cured composite part could be improved.
How we Quickened the Cycle Time
Given that Vapour Chanmbers operate similarly to ISOBAR® Heat Pipes, we closed one chamber to fully cover all of the mold surfaces during the heating cycle, and used vapour condensation to heat all of them. while During the cooling cycle, we utilized liquid evaporation.
NOTE: These mold surfaces would have uniform surface temperature distribution due to the large latent heat released during the condensation / evaporation process, as long as certain mechanisms existed to keep the fluid flowing continuously inside this chamber.
Enhancing the Heating Cycle
During the heating cycle, heat energy was applied to the bottom of the chamber which resulted in vapor moving up to the internal mold surface and condensate coming down to the heating section by gravity. This heating cycle would have the ability to work continuously due to the heat force applied as well as gravity. For the cooling cycle the top surface would have to be cooled down, this meant that the fluid would need to move from the base of the mold, against gravity, to the top surface where it would evaporate and lower the temperature of the mold surface. From a design stand point an engineered wicking structure would be required to generate sufficient capillary force to lift the fluid up and continue the cycle.
Enhancing the Cooling Cycle
To enhance the cooling cycle, Acrolab engineered an internal cooling channel into the mold. After a series of performance tests on this new mold design concept, Acrolab provided a detailed report to the client outlining the performance capabilities of the vapor chamber composite mold and operating instructions for the mold.
The prototype composite mold was then sent to the client for prototype production of the composite part. This study has laid the foundation for vapor chamber integration into many other tool and mold platforms in other sectors.