CPT International 3/2019

SAND REGENERATION
Perfection is the drive” is the mission
statement of the Jürgens
foundry in Emsdetten, Germany.
This includes production processes that
are optimally coordinated with one
another, that are continuously improved,
and that are adapted to the particular
requirement profile. A good
example of this is the old molding
material preparation plant with its Muller
mixer. After 2012 it no longer met
the demands of a foundry specializing
in gray cast iron and spheroidal graphite
iron.
Eirich mold material preparation
– turning old into new
“We were thinking about expanding silo
capacities when we stumbled across a
two- or three-year-old Eirich molding
sand preparation plant with a Webac
cooler. We were able to purchase the
equipment from the insolvency assets of
a foundry in southern Germany. That
was a stroke of luck”, remembers Thomas
Poggemann, Production Manager at
the Jürgens foundry in Emsdetten. Jürgens
decided to build a new hall, which
was seamless connected to the secondhand
sand preparation plant (in tower
design) with all central system components.
A competent partner was found
– the Gustav Eirich engineering works in
Hardheim, Germany – who carried out
the detailed engineering and assembly
of the machine technology, as well as
the steel construction including the
enclosure. The delivery also included the
complete control system and an AT1
inline tester device for automatically
measuring compactability and shear
strength. The Jürgens foundry inplemented
the conveyor system from VHV Anlagenbau,
Hörstel, Germany. Preventive
molding material control was achieved
using SandExpert software from Eirich
for the continuous registration and analysis
of batch data. The control solution
and quality package together form the
basis for achieving without human intervention
a high quality molding material
preparation despite challenging conditions.
A demanding task in view of the
foundry’s wide range of castings.
Control via pattern catalog database
Jürgens currently produces molding
boxes for about 4,500 different castings
using two HWS molding lines, both operated
with the Seiatsu mold process. The
casting weight of the small molding line
Figure 1: The second-hand Eirich mixer at
the Jürgens foundry uses pre-water.
is between 20 and 140 kg liquid iron,
while that of the large mold line is between
100 and 1,000 kg. The two molding
lines run in parallel. Two completely
different castings are made at the
same time. “The molding material must
be right for both patterns, although the
iron-to-sand ratios are very different,”
according to Thomas Poggemann.
Manually calculating the best molding
material recipe involved much time and
effort considering the frequent changes
of mold. Today, the mold material preparation
is programmed for each specific
mold and processing is fully automated.
This method of operation requires a
lot of advance work – which Thomas
Poggemann and his team have carried
out excellently. Box weight, box size,
liquid iron, required bentonite content,
required compression strength, compactability,
shakeout properties, core decay
– they defined all this meticulously for
each pattern plates,” confirms
Klaus-Dieter Knapp with appreciation.
He is supporting the Jürgens Foundry as
an Eirich service technician and was
already involved in the planning and
design phase
Objective: homogeneous
return sand
The software automatically calculates
the composition of the molding material
when there is a pattern plate
change at the molding line. This takes
into account the values from the pattern
catalog so that the return sand
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