CPT International 3/2019

Sand core hardening:
Digital quality with new
ACS-Technology
Corebox for inorganic sand
core test bars adjusted to
ACS technology at DISA core
shooter.
Sand cores are building the back-bone of the foundry business to deliver constantly
improving foundry products. The sand core requirements stretch from high dimensional
accuracy to easy core removal while at the same time demanding the lowest possible
cost. Sand core quality plays an important role as quality defects of sand cores usually
results in defects of final foundry products.
By Wolfram Bach, Sülzetal, and Prof. Gotthard Wolf, Freiberg
Photo: ACS
All these requirements are driven
to ensure the highest possible
quality for the final foundry
product at the lowest price.
All inorganic sand core manufacturing
process offer various parameters to
adjust the sand core quality. The parameters
can be grouped into five main
critical steps during the manufacturing
process:
1. Sand core & core box design
2. Shooting process
3. Curing process
4. Handling & Storage
5. Application
All processes above have a direct impact
on the quality of the sand cores. The
curing process (Step 3.) has the biggest
operational impact on the individual
sand core quality while all other process
parameters are de-signed upfront and
to ensure reliable quality. The main reason
why the curing process is so critical,
is that it requires heat application to
the individual sand core to ensure sufficient
sand core strength.
Heat application processes can be
simulated but are difficult to control in
real time. Especially if heat is generated
externally and conveyed into the core
box for conventional core boxes. The
Tool design.
common heat applications in the core
box use either thermo oil or heating
rod to generate the heat and to heat
up the core box to tar-get temperature.
Additional heat energy is applied to the
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