Cast Metal & Diecasting Times July/ August 2016 July/August 2016 | Page 23

FINISHING | 21

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Dry ice cleaning proves its worth
Progress Casting Group is cleaning core boxes and moulds faster and quieter with Cold Jet dry ice micro particles.

It takes one worker 10 minutes to clean a mould while it remains hot and online, whereas previously, it took two or three workers three-four hours to clean
one or two moulds.

The Progress Casting Group in Minnesota,
USA, was founded out of Continental
Castings in 1962 and the Progress Foundries
in 1982. The Plymouth foundry specialises in
precision diecasting and sand castings for the
automotive, aerospace and defence industries.
The refractory coating (release agent), the
resin spray buildup, sand casting components
and core residues on the core boxes and low
pressure casting moulds were being removed
by sand blasting and manual brushes. Both
cleaning processes are slow and ineffective,
causing damage to machines and putting
workers’ safety at risk. Sand blasting destroys
the urethane on the moulds and both
methods routinely destroy the vents on the
core boxes.

The challenge
The Progress Casting Group was looking for
a cleaning method that removes the refractory
coatings and other residual material without
damaging mould vents. In addition, uneven
refactory coating should be avoided, as this
can affect the quality of the final product and
the speed of production.
Release agents and residual materials
should also be removed from the surface
as ‘smooth as a feather’, without rounding
the corners, an important prerequisite for
product quality. The area around the tool
should be clean and safe for employees. The
tools need to be cleaned after every use to
minimise downtime and the moulds should
still be hot to reapply the refractory coating.
The problem with steel shot, glass bead and
sandblasting is the possibility of mould vent
damage and urethane damage on moulds.
The rounding of mould edges leads to flash
on the parts, shortens mould life and creates
secondary waste and potential eye injuries
from atmospheric contaminants.
Manual cleaning with chemicals and
brushes is extremely labour-intensive and
potentially harmful to workers, causing long
downtime and inefficient and ineffective
clean in some places.

Regular 3mm dry ice pellets.

Dry ice micro particles.

The solution
Cold Jet is the only supplier that offers
the patented shaved dry ice technology for
dry ice micro particles on the market. Many
small dry ice micro particles clean the surface
faster, smoother and much quieter than
conventional 3mm pellets.
The dry ice blast cleaning process is similar
in concept to sand or soda blasting, where
the respective media is accelerated through
a pressurised airstream. The main difference
is that rather than sand or soda, Cold Jet’s
system uses recycled CO2 in the form of dry
ice micro particles to clean surfaces.
The CO2 micro particles are accelerated at
supersonic speeds through a specialised hose
and nozzle. Once the micro particles hit the

Casting after dry ice cleaning.

mould surface, the combination of kinetic energy
and thermal gradient effects of the dry ice blast
breaks the bond between the surface and the
residue. On impact with the tool surface, the CO2
sublimates, returning to its natural gas form,
leaving no secondary waste to clean up.
The result
The Progress Casting Group tested a Cold
Jet micro particle dry ice cleaning system
and used it to clean its most delicate screen
vents at full blast. Even at maximum blast
aggression, there was no damage to the parts
and the moulds looked brand new.
“The system was shown to the President
of the company and after the test, he turned
around and said: Buy it immediately!”
comments Daryl Hesch, Tooling Supervisor
at Progress Casting. “Within two days, the
Cold Jet dry ice blasting system was in our
company and at work.”
Today, it takes one worker minutes to
clean a mould while it remains hot and
online, whereas it took two or three workers
three-four hours to clean one or two moulds
previously. The tooling supervisor estimates
savings of $400-$500 per mould with the
system. “We estimated that it would pay for
itself in six months but it took only a month”
says Daryl Hesch.
www.coldjet.com

Cold Jet dry ice pelletiser.

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