OF DRY ICE BLAST CLEANING
CO2 / dry ice blasting is being effectively used in a wide array
of applications from heavy slag removal to delicate semiconductor
and circuit board cleaning. Imagine a process that can be used on-line
without damaging equipment or requiring a machine "teardown". Unlike
conventional toxic chemicals, high-pressure water blasting and abrasive
grit blasting, CO2 / dry ice blasting uses dry ice particles in
a high velocity air flow to remove contaminates from surfaces without
the added costs and inconvenience of secondary waste treatment and
In the early 1930's, the manufacture of solid phase
carbon dioxide (CO2) became possible. During this time, the creation
of "dry ice" was nothing more than a laboratory experiment. As the
procedure for making dry ice became readily available, applications
for this innovative substance grew. Obviously, the first use was
in refrigeration, and dry ice is still widely used in the Food Industry
for packaging and protecting perishable foods
saw stories of the U.S. Navy experimenting with dry ice as a blast
media for various degreasing applications. In May 1963, Reginald
Lindall received a patent for a "method of removing meat from bone"
using "jetted" Carbon dioxide particles. In November 1972, Edwin
Rice received a patent for his "method for the removal of unwanted
portions of an article by spraying with high-velocity dry ice particles".
Similarly, in August 1977, Calvin Fong received a patent on "Sandblasting
with pellets of material capable of sublimation".
The work and
success of these early pioneers led to the formation of several
companies in the early 1980's that pursued the development of dry
ice blasting technology. In 1986, Cold Jet®, Inc. was founded
in the State of Ohio by Mr. Newell Crane.
ice pelletizers and dry ice blasting machines entered the industrial
markets in the late 1980's. At that time the blasting machines were
physically large, expensive, and they required high air pressure
for operation (pressures greater than 200 psi or 13.8 bar). As the
CO2 / dry ice blasting technology advanced, the dry ice blasting
machines' size and cost dropped, and today, the latest nozzle technology
has made blasting effective at shop air pressures (80 psi or 5.5
Is Dry Ice?
Dry ice is the solid form of Carbon Dioxide (CO2),
which is a colorless, tasteless, odorless gas found naturally in
our atmosphere. Though it is present in relatively small quantities
(about 0.03% by volume), it is one of the most important gases we
is a natural media that serves many life sustaining purposes. It
is a key element in the carbon cycle; it is the only source of carbon
for the carbohydrates produced by agriculture; it stimulates plant
growth; and it helps to moderate the temperature of the earth overall.
Animal respiration is believed to add 28 million tons of Carbon
Dioxide per day into the atmosphere. By contrast, the U.S. CO2 industry
can supply only 25,000 tons per day and 95% of this amount is from
by-product sources, or less than 0.04% of the other sources combined.
a low temperature of -109° F (-78° C), solid CO2 (dry ice)
has an inherent thermal energy ready to be tapped. At atmospheric
pressure, dry ice sublimates directly to vapor without going through
a liquid phase. This unique property means that the blast media
simply disappears, leaving only the original contaminant to be disposed
of. In addition, blast cleaning in water sensitive areas is now
grade of carbon dioxide used in dry ice blasting is the same as
that used in the food and beverage industry and has been specifically
approved by the FDA, the EPA and the USDA. Carbon dioxide is a non-poisonous,
liquefied gas that is both inexpensive and easily stored at work
sites. Of equal importance is its non-conductive and non-flammable
is a natural by-product of several industrial manufacturing processes
such as fermentation and petrol-chemical refining. The CO2 given
off by the above production processes is captured and stored without
losses until needed. When the CO2 is returned to the atmosphere
during the blasting process, no new CO2 is produced. Instead, only
the original CO2 by-product is released.
in Table 1 are the physical properties and conversion factors
for CO2 in its various forms:
1. Carbon Dioxide (CO2
lbs/ft3 at -109° F / 1565 kg/m3 at -78°
lbs/ft3 at 0° F / 1022 kg/m3 at -18°
lbs/ft3 at 32° F / 1.974 kg/m3 at 0°
F at 75.1 psia / -56.6°
C at 5.2 bar absolute (triple
F / -78.5°
scf (gas)/lb / 0.544 m3 (gas)/kg (liquid at 0°F / -18°C
305 psia / 21 bar absolute)
lb snow / lb liquid at 0° F / .46 kg snow / kg liquid
lb snow / lb liquid at -55.0° F / .56 kg snow / kg
liquid at -48°C
dry ice blasting, there are several methods used to manufacture
the dry ice blasting media. One technique is to shave dry
ice granules from a solid CO2 (dry ice) block at the blasting machine.
This generally produces sugar-crystal sized dry ice granules, which
must be used quickly due to rapid sublimation (which is due to their
high surface area-to-volume ratio).
is to manufacture hard pellets of dry ice in a pelletizer
then immediately blast with the pellets or store the pellets in
an insulated container until they are needed. These dry ice pellets
are generally on the order of 0.08" to 0.12" (0.2cm to
0.3cm) in diameter, and 0.1" to 0.4" (0.25cm to 1cm) in
dry ice is manufactured by flashing pressurized
liquid CO2 into snow, and then compressing the snow into solid form.
The snow is either directly nuggetized into pellets (mechanical
compression) or is extruded into solid pellet form through a die
under hydraulic pressure. The latter process allows for a more efficient
conversion from the liquid phase to the solid phase. Generally,
it is desirable to have dry ice pellets that are well compacted
to minimize the entrapment of gaseous CO2 and/or air which may affect
As seen in Table
1, the yield achieved when flashing liquid carbon dioxide into
snow increases as the temperature of the liquid CO2 decreases, so
it is important to pre-chill the incoming liquid CO2 via heat exchangers
with the outgoing CO2 vapor. Figure 1 is a block diagram
showing a basic pelletization process.
1. Basic Pelletization Process.
Several manufacturers make dry ice pelletizers, which may prove
beneficial to have on-site for customers with high pellet demand.
Facilities required for such an arrangement are generally as follows:
a refrigerated liquid CO2 tank, a pelletizer, and liquid CO2 lines
to reach the equipment.
make combined dry ice pelletizer/blast machines, which manufacture
the dry ice and then blast it all in one operation. Facilities required
for such an arrangement are: An air compressor (typically either
120 psi at 250 SCFM / 8.3 bar at 7.1 m3/min or 350 psi at 250 SCFM
/ 24.1 bar at 7.1 m3/min), a liquid CO2 tank, a pelletizer/blast
machine, a compressed air hose and liquid CO2 lines to reach the
equipment, a blast hose from the machine to the blasting operation,
and the appropriate nozzle(s) for the application. This equipment
is best suited to high-volume, continuous dry ice blasting applications
where the cost savings of manufacturing pellets on-site justifies
the capital expenditure for the system. ( See: Cold Jet's
Integrated Systems and FlashJet®).
Does Dry Ice Blasting Work?
Ice blasting is similar to sand blasting, plastic bead blasting,
or soda blasting in that a media is accelerated in a pressurized
air stream (or other inert gas) to impact the surface to be cleaned
or prepared. With dry ice blasting the media is solid carbon dioxide
(CO2) particles. One unique aspect of using dry ice particles as
a blast media is that the particles sublimate (vaporize) upon impact
with the surface. The combined impact-energy dissipation and extremely
rapid heat transfer between the dry ice pellet and the surface causes
the instantaneous sublimation of the solid CO2 / dry ice into gas.
The gas then expands to nearly eight hundred times (800x) the volume
of the dry ice pellet in a few milliseconds in what is effectively
a "micro-explosion" at the point of impact. Because of
the solid CO2 vaporizing, the dry ice blasting process does not
generate any secondary waste. All that remains to be collected is
the contaminate being removed.
As with other
blast media, the kinetic energy associated with dry ice blasting
is a function of the particle mass' density and impact velocity.
Since CO2 / dry ice particles have a relatively low hardness, the
process relies on high particle velocities to achieve the needed
impact energy. The high particle velocities are the result of supersonic
propellant or airstream velocities.
blast media, the CO2 / dry ice particles have a very low temperature
of -109° F (-78.3°C). This inherently low temperature gives
the dry ice blasting process unique thermodynamically induced surface
mechanisms that affect the coating or contaminate in greater or
lesser degrees, depending on the coating type. Because of the temperature
differential between the dry ice particles and the surface being
treated, a phenomenon known as "fracking" or thermal shock
can occur. As a material's temperature decreases, the material becomes
embrittled, enabling the particle impact to break-up the coating.
See Figures 2 and 3.
2. Thermal shock induces micro-cracking in the surface coating
3. CO2 gas expansion and pellet kinetic effects break away and remove
Also, the thermal
gradient or differential between two dissimilar materials with different
thermal expansion coefficients can serve to break the bond between
the two materials. This thermal shock is most evident when blasting
a non-metallic coating or contaminate bonded to a metallic substrate.
companies examining the dry ice blasting process are concerned with
the effect the thermal shock will have on the parent metal. Studies
have shown that the temperature decrease occurs on the surface only,
so that there is no chance of thermal stress occurring in the substrate
metal. To illustrate this principle, an experiment was performed
where thermocouples were imbedded into a steel substrate at varying
depths (flush with the surface to 2 mm deep). See Figure 4.
4. Thermocouple Distance From Plate Surface.
A CO2 / dry
ice blast jet was constantly swept across the test specimen for
30 seconds (a relatively long dwell time for this process) and the
thermal couples recorded the changing temperatures at the various
depths. As shown in Figure 5, the surface-mounted thermocouple
shows a temperature drop each time the blast jet passed directly
upon the it (50° C in about 5 seconds). In contrast, the thermocouples
imbedded at various depths in the substrate recorded a slow gradual
drop in temperature corresponding to the overall test plate temperature
drop. The thermocouple 2mm deep only dropped 10° C after 30
seconds. This curve illustrates that the "Thermal Shock"
occurs only at the surface where the coating or contaminate is bonded
to the substrate (Reference 1) and has no detrimental effect on
5. Temperature Response Of Thermal Couples Placed At Various Depths
In The Substrate
to looking at thermal stress is by studying the use of dry ice blasting
in the molded rubber industry. Here, hot steel molds operating at
300+ °F (149+°C) are blasted with -109 °F (-78.3°C)
dry ice particles. The temperature difference between the hot mold
and cold Dry Ice will not
cracking. There are two reasons for this phenomenon. First, as seen
above, the temperature gradient occurs at the surface. Second, the
thermal stresses involved are much less
than those encountered during normal heat treatment.
stress due to a temperature differential can be estimated using
equation 1 where sy
is stress (psi), DT is
temperature gradient (°F), a
is coefficient of expansion and g
is Poisson's Ratio.
parameter values are
and the thermal
stress (psi) is
where the temperature
differential will be 135 °F / 57.2°C (Based on Figure 5).
This temperature gradient leads to a low tensile stress of 30,240
psi / 2085 bar. Even if the mold temperature was brought down to
the temperature of the ice (an unrealistic extreme), the temperature
gradient would be -109 °F - 350 °F which gives 459 °F
/ 237.2°C, for which the corresponding tensile stress is 102,800
psi / 7088 bar. This calculated stress is below the yield point
of steel in the hardened condition. Again, these thermal stresses
would be far less than those encountered during normal heat treatment
where the temperature differentials would exceed 500 °F / 260°C
Even at high
impact velocities and direct "head-on" impact angles,
the kinetic effect of solid CO2 / dry ice particles is minimal when
compared to other media (grit, sand, PMB, etc.). This is due to
the relative lack of hardness of the dry ice particles and the almost
instantaneous phase change to a gas on impact, which effectively
provides an almost nonexistent coefficient of restitution in the
impact equation. Because dry ice blasting is considered non-abrasive
and relies on the thermal effects discussed above, the process may
be applied to a wide range of materials without damage. Soft metals
such as brass and aluminum cladding can be dry ice blasted for the
removal of coatings or contaminates without creating surface stresses
(pinging), pitting, or roughness (Reference 3).
are two general classes of dry ice blasting machines as characterized
by their method of transporting pellets to the nozzle: the two-hose
and the single-hose systems.
In either type of system, the proper selection of blast hose is
important because of the low temperatures involved and the need
to preserve particle integrity as the dry ice particles travel through
In the two-hose
system, Dry Ice particles
are delivered and metered by various mechanical means to the inlet
end of a hose and are drawn through the hose to the nozzle by means
of vacuum produced by an ejector-type nozzle. Inside the nozzle,
a stream of compressed air (supplied by the second hose) is sent
through a primary nozzle and expands as a high velocity jet confined
inside a mixing tube. When flow areas are properly sized, this type
of nozzle produces vacuum on the cavity around the primary jet and
can therefore draw particles up through the Ice hose and into the
mixing tube where they are accelerated as the jet mixes with the
entrained air/dry ice particle mixture. The exhaust Mach number
from this type of nozzle is, in general, slightly supersonic. Advantages
of this type of system are relative simplicity and lower material
cost, along with an overall compact feeder system. One primary disadvantage
is that the associated nozzle technology is generally not
adaptable to a wide range of conditions (i.e. tight turns in a cavity,
thin-wide blast swaths, etc.). Also, the aggression level and strip
rate of the two-hose system is less than comparable to single-hose
In a single-hose
system, particles are fed into the compressed
air line by one of several types of airlock mechanisms. Reciprocating
and rotary airlocks are both currently used in the industry. The
stream of pellets and compressed air is then fed directly into a
single hose followed by a nozzle where both air and pellets accelerate
to high velocities. The exhaust Mach number from this type of nozzle
is generally in the 1.7 to 3.0 range, depending on design and blast
pressure. Advantages of this type of system are wide nozzle
adaptability and the highest available blast aggression levels.
Disadvantages include relatively higher material cost due
to the complex airlock mechanism.
ice blasting machines are also differentiated into Dry
Ice Block Shaver Blasters and
Dry Ice Pellet blasters.
Shaver machines take standard 60 lb (27.3 kg)
dry ice blocks and use rotating blades to shave a thin layer of
ice off the block. This thin sheet of dry ice shatters under its
own weight into sugar grain sized dry ice particles. These particles
then fall into a funnel for collection. A two-hose delivery system
(see above) is used to transfer the particles at the bottom
of the funnel to the surface to be cleaned. The low mass of these
particles combined with the inefficient two-hose system limits the
block shavers to light duty cleaning. Because the shaved ice machines
deliver a dry ice particle blast with high flux density (Number
of particles striking a square area of surface per second), they
are effective on thin, moderately hard coatings such as an air dried
oil based paint. The disadvantage of the ice shaver is that
the dry ice particle's size and flux density, as well as its velocity,
machines have a hopper that is filled with pre-manufactured
CO2 / dry ice pellets. The hopper uses mechanical agitation
to move the pellets to the bottom of the hopper and into the feeder
system. As stated earlier, the pellets are extruded through a die
plate under great pressure. This creates an extremely dense pellet
for maximum impact energy. The pellets are available in several
sizes, ranging from 0.04" to 0.12" (0.1 cm to 0.3 cm)
in diameter. With a single-hose delivery system, the final pellet
size and blast flux density exiting the nozzle is governed by the
type of blast hose (hose diameter and interior wall roughness) and
nozzle used. Because of its design, the single-hose dry ice pellet
blasting units are capable of "dialing-in" the correct
blast type needed for a wide range of individual coatings or contaminate
example, soft coatings such as rubber,
silicone, foams and waxes, release agents, food ingredients, etc.
need large dry ice pellets with low flux density for maximum strip
rate and efficiency. These coatings require maximum thermal energy
(i.e. dry ice pellets with large mass) and large spacing between
the pellets (i.e. low flux density) for optimum cleaning performance.
In contrast, hard coatings such as paints, varnish, baked on sugars,
carbon build-up, etc. require smaller particle size with high flux
density and high particle velocity.
Dry ice blasting
machines are further differentiated into all-pneumatic
and electro-pneumatic types.
a pneumatically operated dry ice particle feed mechanism and controls.
This may include the use of air motors. The advantage of
such a machine is the availability of compressed air at the blast
locations, especially outdoors. One disadvantage is that
the operation of the machine may be susceptible to disruption due
to moisture or contamination in the compressed air supply. In addition,
these machines are more prone to freeze-ups and are better suited
for light duty spot cleaning applications. Also, if the machine
is powered by an air motor, it will have a continuous exhaust of
oily air. This same air motor can easily be flooded with water if
the air system is not adequately dried.
machines are truly "Environmentally Friendly"
because there is no oily exhaust and these machines are more tolerant
of moisture and contaminants in the air supply. The electro-pneumatic
machines rarely freeze-up which makes them ideal for automated line
applications where around-the-clock dry ice blasting is required.
Also, these machines provide pulse free blasting for uniform cleaning
and efficient use of the dry ice. There is, however, a slight inconvenience
factor associated with supplying both electrical power and compressed
air to the machine at each blast location.
One of the most
challenging technologies associated with either type of blast machine
is the achievement of smooth, continuous pellet feed. One surprising
property of dry ice is that it is not smooth or slippery like water
ice nor is it smooth-flowing like sand or glass bead. Instead it
is somewhat resistant to flow. Because of this, dry ice blast machines
tend to have various agitators, augers and other devices in the
hopper to improve pellet flow. Generally, the poorer the quality
of the dry ice - containing, for example, water ice build-up or
a large percentage of CO2 "fines" or snow - the more difficult
its flow through a system. An additional property of dry ice is
that it is extremely cold and will draw moisture out of the surrounding
air in the form of frost. Therefore, the machine must be tolerant
of repeated freeze-thaw cycles and the associated moisture accumulation
that will take place over time.
difference between a high-quality dry ice blasting machine and a
mediocre one lies in the unit's ability to do a cleaning job quickly,
cost-effectively, and with the reliability of smooth and continuous
dry ice pellet flow under real-world conditions.
The nozzle is where the dry ice particles are accelerated
to the highest velocity possible in order to create an effective
dry ice blast stream. Figure 6 shows the schematics of the
two types of nozzles used for dry ice blasting. The science of two-hose
ejector nozzles compared to single-hose
convergent-divergent supersonic nozzles operating under the
same conditions (i.e., air volume, pressure, temperature, CO2 particle
mass...etc.), shows a significantly higher efficiency capability
for the described single-hose type nozzles. This difference in capability
is directly related to the two-hose ejector nozzle's overall supplied
energy being used not only to accelerate the CO2 / dry ice particles,
but also to create the vacuum pulling the secondary pellet flow
through the secondary hose. Then, more energy is drained to mix
this low velocity particle flow with the high velocity jet flow
in order to accelerate the dry ice particles through the two-hose
nozzle. In simple terms, the net resultant energy available for
pellet acceleration is inherently lower for two-hose systems because
much of the available energy is lost simply in combining the CO2
/ dry ice particle flow with the air-jet flow.
6. CO2 / Dry Ice Blasting Nozzle Types
Since the size
of the dry ice particles affect cleaning performance, a dry ice blasting
system should have the flexibility to "Dial-In" the correct
particle size. This can be done in a couple of different ways. First,
the size of the dry ice pellet being produced by the pelletizer may
be varied. Once the pellet is in the dry ice blasting machine's hopper,
the size of the pellet reaching the surface to be cleaned can be varied
in several ways. The diameter and type of blast hose used will either
keep the pellet intact or break it up into smaller particles. Also,
the nozzle may be intentionally mis-expanded to produce partially
destructive shockwaves within the nozzle. Both techniques are used
independently or together to optimize the dry ice particle size, blast
stream velocity, and flux density for any cleaning job.
When sand or
any similar media with a very small diameter is used in blasting,
the size of the nozzle throat is very large compared to the blast
media. In dry ice blasting, however, the nozzle throat may only
be slightly larger than the dry ice particle being accelerated.
2 is a chart indicating the approximate
size of a round nozzle throat for four different levels of blast
pressure at a constant airflow of 200 Standard Cubic Feet per Minute
(SCFM) / 5.7 m3/min, a typical flow rate available for blasting
operations. At higher pressures, the dry ice particle size needs
to be smaller to correspond with the smaller throat size. The high-pressure
blast stream is described as high-velocity small particles with
high flux density. Again, this particle blast profile is best suited
for removing hard coatings such as paint. The chart shows a larger
nozzle throat diameter corresponding to low pressure operations.
As stated above, large pellets impacting the surface with low flux
density is ideal for cleaning soft coatings.
2. Pressure To Nozzle
Throat Diameter Relationship
Dry ice blasting
nozzles tend to be long as a result of the requirement to accelerate
particles to as high a velocity as possible. Therefore, a very long
nozzle with a small throat tends to have a high scrubbing-surface-area
per unit airflow. This explains the higher efficiency of low-pressure
dry ice nozzles compared to high-pressure nozzles. A minimum cost
dry ice blasting system for industrial use has a design point at
80 psi / 5.5 bar, a typical pressure for a plant air system.
of CO2 / Dry Ice Blasting technology
The natural sublimation of dry ice particles eliminates the cost
of collecting the cleaning media for disposal. Containment and collection
costs associated with water/grit blasting procedures are also eliminated.
/ dry ice blasting systems provide on-line maintenance capabilities
for production equipment (online cleaning), time consuming and expensive
detooling procedures are kept to a minimum. Dedicated cleaning cycles
are no longer required as preventive maintenance schedules can be
adopted, which allow for equipment cleaning during production periods.
As a result, throughput is increased without the addition of labor
or production equipment.
of Equipment's Useful Life
Unlike sand, walnut shells, plastic beads
and other abrasive grit media, dry ice particles are non-abrasive.
Cleaning with dry ice will not
wear tooling, texture surfaces, open tolerances, or damage
bearings or machinery. In addition, on-line cleaning eliminates
the danger of molds being damaged during handling from press to
cleaning area and back.
Unlike steam or water blasting, CO2 / dry ice blasting will
not damage electrical wiring, controls, or switches. Also, any possible
rust formation after cleaning is far less likely with dry ice blasting
than with steam or water blasting. Also, when used in the Food Industry,
dry ice blasting reduces the potential for bacteria growth inherent
to conventional water blasting.
Carbon dioxide is a non-toxic element which
meets EPA, FDA, and USDA* industry guidelines. By replacing toxic
chemical processes with CO2 / dry ice blasting systems, employee
exposure and corporate liability stemming from the use of dangerous
chemical cleaning agents can be materially reduced or eliminated
completely. Since CO2 gas is heavier than air (CO2 gas displaces
oxygen), care must be taken if blasting in enclosed areas or down
in a pit.
CO2 Blast applications
Dry ice blasting cleans unwanted release agents ("parting agent")
and/or residual material build up from the mold's contact surfaces.
That is to say that the build-up of release agents or residual product
from the hot mold are easily removed. Dry ice blasting allows the
tools or molds to be cleaned while the mold is hot and still in
the press. This reduces "press downtime due to cleaning"
by 80% to 95%. Since the process is non-abrasive, CO2 / dry ice
blast cleaning will not wear the tools or open critical tool tolerances.
Furthermore, "micro vents" are typically cleaned by dry
ice blasting. This eliminates the hand-drilling of plugged vents
needed for optimum gas escape. Examples of molds/mixers cleaned
by Cold Jet are:
- Rubber Molds
- Tire Molds
- High Density
- PET Molds
- Foam Molds
- Banbury Mixers
There are many types of dies and sometimes the word "die"
is practically synonymous with "mold". And, as with molds,
the dry ice blasting application is usually quite successful. Both
molds and dies usually operate at elevated temperatures, which increases
the cleaning rate and the attractiveness of on-line cleaning. Examples
- Core Boxes
- Paper Plate
Residual sugars left behind after baking can be readily removed
from fixtures in most cases. Here, as with molding, heat may enhance
removal speed and characteristics. In many cases the dry ice blasting
application may be performed on-line.
A key benefit
of using dry ice blasting to replace some of the general cleaning
(done with water, detergents and sanitizers) is moisture reduction.
Indeed, moisture promotes the growth of bacteria -- particularly
salmonella -- whereas dry ice blasting actully inhibits bacteria
growth. Furthermore, economics have led to the on-line cleaning
of fixtures including wafer plates, waffle irons and other similar
batter or dough baking and product forming fixtures, oven bands
and conveyor belts.
/ dry ice blasting has been proven to remove and/or destroy significant
biofilm build-ups of listeria and salmonella. Typical applications
- Cookie Oven
- Baking Ovens,
Shelves and Trays (without shutting down or disassembly)
- Wafer plates
(Carbon build-up removal)
- Flight &
- Tanks and
Vessels (removes Ingredient build-up)
- Screws and
There are many names and types of production fixtures, but virtually
any item that is part of a production process and is difficult to
clean on-line or during production hours by traditional means may
be an excellent dry ice application; applications such as:
weld slag from Robotics, Fixtures, Carriers
Oils and Grease from chains, machinery, etc.
In the Flexographic Printing Industry,
inks and varnish polymers are designed to adhere to most surfaces,
resist scratches, and, in some instances, be solvent resistant.
These characteristics, which make their use so attractive, also
make the removal of dried ink very difficult. Ink buildup on the
gears and deck guides causes poor alignment and results in low print
quality. To compensate for this phenomenon, plate mounting generally
needs to be adjusted several times in order to register critical
graphics to produce an acceptable quality level. Generally, each
"press run" to check the register of the colors results
in thousands of feet of wasted material. This inherently wasteful
process can now be eliminated due to the on-line precision cleaning
ability of dry ice blasting.
We can't predict
the future, but with environmental issues and legislation becoming
more and more stringent, one thing is certain: the successful shops
of the future will have fully incorporated the CO2 / dry ice blasting
process into their operations.
* EPA: Environmental
Protection Agency, FDA: Food and Drug Administration, USDA: United
States Department of Agriculture
- The Production
Engineering Research Association of Great Britain (PERA), Cold
Jet® Thermal and Surface Cleaning Characteristics,
- James A.
Snide, CO2 Pellet CleaningA
Preliminary Evaluation, Materials & Process
Associates, Inc., October 12, 1992.