Dry ice blasting for parts finishing is a non-abrasive process that removes flash and burrs from individual molded or machined parts. It’s suitable for most plastic materials and metal components with fine burrs. To remove surface defects, a stream of dry ice particles is propelled by compressed air and “blasts” the part. Unlike conventional sand or soda blasting, however, dry ice blasting is effectively media-less. That’s because when dry ice pellets hit part surfaces, the media turns to a gas and evaporates.
This process, known as sublimation, means that dry ice won’t lodge in part geometries or attach to part surfaces. By contrast, abrasive finishing processes may require cleanups to remove residual media. Plus, dry ice blasting can reach wide areas or remove only unwanted surface features. By guiding the blast over a focused area, a skilled operator can remove part defects while leaving other surfaces alone. Unlike the secondary waste associated with abrasive finishing, flash and burrs are relatively easy to cleanup.
Dry Ice Blasting vs. Cryogenic Deburring and Cryogenic Deflashing
Dry ice blasting can be used as a standalone finishing process. It can also be used with cryogenic deflashing or cryogenic deburring, batch processes that use gaseous nitrogen to freeze the parts while they’re tumbled and blasted with cryogenic-grade polycarbonate media. As a leading provider of cryogenic solutions, Nitrofreeze® offers a portfolio of services. Dry ice blasting has its advantages, but when is it a recommended instead of cryogenic deflashing or cryogenic deburring?
Very Small Holes or Cavities
Dry ice blasting is recommended for holes and cavities with less than a 0.015” (0.381mm) opening. Although dry ice sublimates too quickly for reliable measurements at smaller sizes, Nitrofreeze® has cleaned cavities as small as 0.003” (0.0762mm) with dry ice blasting. Cryogenic deflashing and cryogenic deburring can also clean smaller inner diameter features, but the polycarbonate media that’s used tends to lose its aggression with holes and cavities that are smaller than 0.015” (0.381mm).
Excessively Thick Flash or Burrs
The polycarbonate media for cryogenic deflashing and cryogenic deburring is available in a wide range of sizes. Nitrofreeze® can select a media size with the right amount of aggressiveness, but some mold flash or burrs are excessively thick or large. For these part defects, dry ice blasting is used because of its high-velocity particles and superior aggression. At 140PSI, dry ice pellets can remove the heaviest plastic defects and even fine metal burrs.
Large and Heavy Parts
Some plastic parts are too large to fit inside the 24” (60.96cm) baskets that are used in cryogenic deflashing and cryogenic deburring equipment. When that’s the case, dry ice blasting can be used instead. Large plastic parts with delicate outer diameter features are also good candidates for dry ice processing. Heavy metal parts that weigh less than 0.5 lbs. (0.226796 kb) and that have cosmetic tolerances are also recommended for dry ice blasting.
Challenging Flash or Burr Locations
Some molded and machined parts have challenging features such as deep, narrow through-holes that require deflashing and deburring at precise angles. Cryogenic processes can remove flash and burrs from hard-to-reach areas such as cross-holes and blind-holes, but within limitations. For holes with very narrow openings, the area that the media can reach is extremely shallow. Here, dry ice blasting for parts finishing may be an appropriate substitute.
Nitrofreze® Dry Ice Blasting for Parts Finishing
Is dry ice blasting the right choice for removing mold or flash from your plastic or metal parts? When is cryogenic deflashing and deburring recommended instead? Contact the experts at Nitrofreeze® to review your requirements. If you part is a viable candidate, we can perform sampling to demonstrate the process. The consultation is free of charge.
To learn more, contact us at the phone number and email listed below.
(508) 459-7447 x109 | info@nitrofreeze.com