The possibilities for additive manufacturing have been growing at a fast pace
and, according to one technology player, the industry is now focused on "bringing the buzz down to practicality." The Euromold trade fair in Germany last
December offered an array of unique and exciting AM displays, but the real story
was the actual technologies and applications for the manufacture of functional
parts, including end-use components and industrial tooling. On the following
pages is a sampling of what we saw at this show.
Molds and Cores Built in Days without Tooling
This photo shows a diesel engine cylinder head, along with part of the sand mold
and some of the sand cores that were required to cast it. This sand mold and the
cores were created using a 3D printing process developed by Voxeljet.
According to Tom Mueller, principal of Thomas J. Mueller and Associates,
casting such a cylinder head requires several tools, including patterns for the
cope and drag (the top and bottom parts of the sand mold), and a number of
core boxes (molds used to create sand cores that will form undercut features
in the head). This process can take thousands of dollars and several weeks
to complete. Castings with complex fow situations, like cylinder heads and
pumps, often can only be optimized by an iterative design-build-test-redesign
process, he says. However, the cost and time required to create the tooling for
each design iteration makes the process very costly and time consuming.
With the Voxeljet process, molds and cores can be built without tooling in a
few days, making this iterative process more cost- and time-effective. In fact,
a designer can now simultaneously evaluate several design alternatives to
further cut the time required to optimize the design, Mueller says.
Cost-Effective Casting
ExOne's largest additive manufacturing
machines print parts in sand for use in metal
casting. Making casting mold components
directly in sand, without any need for a pattern
or core box, enables not only more cost-effective casting as the caption at left describes,
but also casting of complex geometries that
would not have been practical or even possible with conventional casting molds. The
sand-printed part above is an example of an
intricate, core-like component that was easy
to produce through 3D printing.
AdditiveManufacturingInsight.com February 2014 — 9