FOR AUTO RTM

Fused-Particle Tooling NEWS
Placement of particles in the tool frame
With the vacuum pulled on both films, intricate details of the master are now visible.
Next a series of fine and coarse particles are poured on top of the framed film that
now contains an impression of the master. The particles are spread out across the
length and breadth of the framed film in layers. Fine particles, which will pick up the
impression, are positioned closest to the film face, and coarser particles, which add
mechanical integrity and help the particles interlock, are positioned further back.
Low-cost, rapid toolmaking technique
Although AI never implemented either concept, Van Ert says when
he retired a few years ago, he started playing with it again — this
time, not to find an energy-absorbing material but, instead, to look
for the optimum combination of particles and bagging materials
to make low-pressure compression molding tooling. The goal?
Replicate fairly fine details in the surface of sheet-form plastic
and composite parts while keeping costs and
manufacturing times down vs. conventional
tooling alternatives.
Van Ert also is the inventor of
differential pressure molding
(DPM), a low-cost variation
on compression molding.
Van Ert is also the inventor of differential-pressure
molding (DPM), a compression-type
molding process he developed
at Vantage Technologies during the
past 15 years. A low-cost, low-investment,
low-pressure molding process,
DPM was designed to mold automotive
parts, such as headliners, in developing countries. The process
relies on the pressure differential between normal atmospheric
pressures on the outside of the tool and the reduced pressure on
the inside of the tool to mold parts. Today, it’s used to produce a
variety of thermoplastic composite parts for industries ranging
from transportation to building/construction, renewable energy
and consumer products.
Although Van Ert had long since developed a low-cost and fairly
fast composite tooling technology for use with DPM — standard
tools can be made in several weeks (vs. several months for hard
tooling) and a more costly rapid version can be made in as little
as a few days — he still felt that there was more work that could be
done in this area.
While he was literally tinkering in his garage a few years back
and thinking about the low-cost tooling he wanted to make, he
recalled another experience early at the start of Vantage Technologies.
He’d had a bag of aluminum
powder (commonly used as filler for
epoxy) and had pressed it up against
something while pulling a vacuum and
achieved a very accurate impression of
the object’s shape. He had not perfected
DPM at that point, so he was just trying
to work with different fillers to improve
tool cooling to reduce cycle time. While the
bagged aluminum powder didn’t work for
that purpose, it was yet another idea that Van Ert tucked away.
Later, when he had perfected DPM and was using the process to
make prototype and production parts, he recalls thinking that he
probably could make a tooling system that would work with the
low-pressure DPM process, but didn’t get around to doing it. It
took retirement for him to revisit both ideas.
This time, Van Ert sandwiched a variety of particulate materials
between two thin, flexible films in a sealed rectangular
(0.6m by 1.2m) frame fitted with a vacuum valve. Fine powders
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