It is a process in which particles of solid carbon dioxide (dry ice) are propelled at high velocities to impact and clean a surface. The particles are accelerated by compressed air, usually in the range of 80-100 psi. If higher pressures are required, all of our equipment is capable of blasting up to 220 psi.
It originated at Lockheed in the 70’s when a coatings engineer, Calvin Fong, was researching ways to rejuvenate aircraft primer.
When removing a brittle contaminant such as paint, the process creates a compression tension wave between the coating and the substrate. This wave has enough energy to overcome the bonding strength and literally pop the coating off from the inside out. When removing a malleable or viscous coating such as oil, grease, or wax, the cleaning action is a flushing process similar to high-pressure water. When the particles hit, they compress and mushroom out, creating a high-velocity snow flow that flushes the surface.
Sand blasting is similar to using an ice pick whereas dry ice blasting is similar to using a spatula. Sand cuts or chisels away the contaminant. Dry ice lifts it away.
It sublimates and returns to the atmosphere as carbon dioxide (CO2) gas. CO2 is a naturally occurring element that constitutes less that 1% of our atmosphere.
It moves from an undesirable area to an area where it can be dealt with more easily. If it is dry, it usually falls to the floor where it is swept away or vacuumed during normal maintenance. If it is a wet substance like grease, you take a methodical approach similar to hosing down a driveway. You start at one end and guide it to a collection point where it is vacuumed or squeegeed up.
Generally no. There is an energy threshold at which disbonding will occur. When the disbanding threshold is lower than the damage threshold you can clean without damage. If the reverse is true, damage can occur. Most CO2 applications deal with production equipment (cast iron, tool steel, tool grade aluminium), so there is no damage. We also have success with softer substrates such as plastics, wiring, pure copper, and fabrics, but these must be examined on a case-by-case basis.
You may be able to clean as much as three to five times faster hot than cold. Most contaminants have weaker adhesive strength when hot. In addition, because dry ice sublimates on impact, there is no media entrapment. Grit entrapment is an important reason those who clean with sand, glass beads, or other abrasive media cannot clean in place.
Yes, but generally not as much as you might think. The amount of cooling depends upon three primary factors: a) mass of the targeted surface; b) dwell time and c) ice usage rate. Typically, a tire mold may drop from 350ºF to 325ºF during cleaning. With a very thin mold, the drop can be much greater. Generally, however, cooling is not a concern and only rarely does it affect cleaning performance.
It is unlikely, but it depends on the mass of the targeted object. Heavy molds, for instance, will not be harmed in any way because the drop in temperature is insignificant when compared to the mass of the mold. With thin substrates where tolerances are critical, some testing may be required to determine if the drop in temperature would structurally alter the surface.
Only if you cool the substrate below the dew point which varies depending on local climate. If you’re
cleaning a hot mold, you’re unlikely to cool the mold below the dew point, so condensation is rare.
It is made from liquid CO2. CO2 exists as a liquid only under high pressure. When it drops to ambient pressure (the normal pressure that surrounds us), approximately half turns to gas and half turns to solid. The solid, usually in the form of fluffy snow, is then compressed to form dry ice blocks, pellets or nuggets.
Pressurized liquid CO2 is dropped to ambient pressure to produce snow. This snow is compressed and pushed through a die to make pellets.
It is typical to operate at about 80-100 psi with 120-150 cfm, however your needs will depend on your application. The blasting guns clean effectively using as little air as possible.
All of our standard gun configurations are rated at 220 psi, which is well above the 80-100 psi used in the vast majority of applications, yet the higher pressures can be utilized when needed.
Yes, you can change the rate at the control panel.
Since dry ice is -109ºF, putting it in a freezer won’t help. The best way to extend your shelf life is to store the ice in an insulated bin. Depending on the quality of the bin and how much ice you are storing, your loss due to sublimation should range from 2% to 10% per day.
One person can easily roll any of the portables around the shop floor without any special equipment. Our units are lightweight and can be lifted by one or two people.
The equipment is designed to operate with clean, dry air, which most plants are able to provide, so an additional air dryer is generally required only in exceptional circumstances. You should, however, always blow down your air lines before hooking them up to your CO2 blasting unit. This will eliminate water and sediment that may be present, which prevents these impurities from entering the equipment.
Very little. Our CO2 Blasting units are designed to provide years of trouble-free use with a minimum of maintenance. You must keep oil in the oilier, periodically check the filters, and periodically examine the hoses for cracks and abrasions.
The range of cleaning applications for CO2 is remarkable and is easily demonstrated in just a small sampling of our customer base.
CO2 shines in cleaning production equipment online, because it eliminates the need for masking, cool down and disassembly. Users minimize downtime, which maximizes production efficiency. We have achieved outstanding results cleaning production equipment for foundries, rubber and plastics molders, food manufacturers, printers, and the semiconductor industry. Dry ice blasting is also widely used in the nuclear industry for decontamination.
Anytime waste volume or health risks are a concern, the viability of CO2 should be examined. Because CO2
disappears on impact, it creates no additional waste. Competing processes such as grit blasting or solvents often present disposal problems or health hazards.
