Development of a newly patented process to speed up the hardening of inorganic sand cores


Sand cores are the backbone of modern foundry products and enable the most complex shapes. A newly patented process will improve the inorganic sand core hardening process by up to 33%.

The processes and industry behind the manufacturing of sand cores is constantly evolving to drive more environmentally friendly solutions while also improving the cost and cycle times. Various well-known companies are specialized to offer solutions to modern foundries from sand preparation, core shooting, core hardening and core removal.

For prototyping and small series, additive manufacturing known as 3D-printing is leading the way. For large series the cold box process and inorganic core manufacturing are both evolving while inorganic processes are constantly gaining market share due to raising environmental standards around the globe.

The key concept behind inorganic binders is that heat enables hardening of sand cores. Unfortunately sand and binder compositions have a limited heat conductivity. Therefore the heat is applied externally and transferred as close as possible to the sand cores via potentially complex core boxes. The heat transfer from the core box to the sand cores is supported by good heat conductivity from aluminum to sand. Low heat conductivity within sand are causing shell formations during the curing process as the heat can´t be transferred as fast from the outer core to the inner sand core. Financial aspects do not always justify a 100% curing of the sand cores due to the required times.

The project “ACS – Advanced Core Solutions” developed by Soplain GmbH is therefore focusing especially on the heat generation directly inside the sand cores by the application of electrical currents. This underlying principle of heat generation due to electrical resistance is well known and now applied to sand core manufacturing processes. The benefits are not only faster sand core hardening but also better energy efficiency and reduced maintenance effort as external heat generation outside the core box could be eliminated.

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