Materials and shapes used for blasting
Right choice of blasting media impacts on operating cost of the process, this is the "fuel" of a blaster and the booster of the savings. This small overview is about the shapes and materials used in CM machines today, the purpose it is not to fulfill the argument and each case must be handled and checked to get a tailored answer.
Engineering law governing the process is rather simple: kinetic energy - so controlling speed of shooting and choosing carefully mass of what we are shooting it is the way to succeed.
Size chart reference: SAE J444.
Below shapes description first and materials description follow.
Shapes.
Shots - Spherycal - "S"
Shape is spherical, identified by an "S" followed by some numbers that identify shot's size.
Good results in soft cleaning and deburring.
Usually it is the best shape for shot peening.
Good performances in cleaning and peening processes.
Grits - Angular - "G"
Shape is angular, identified by a "G" followed by some numbers that identify sizes
Really good performances in blasting to obtain a specific roughness and cleaning against hard materials like scale after heat treatments.
Blasting parameters must be carefully controlled to avoid spoiling of parts.
Materials
steel
It's the most popular shot/grit material, available in a wide range of sizes.
Beside the size, hardness of the material strongly impact on the finishing process.
Percentage of dust inside the media bag may vary widely from different producers and influences the cost.
Waste is moderately flammable and can became explosive under certain conditions, must be handled with care.
Storage of steel requires to keep it in a dry place to avoid to be spoiled; CM sells medias inside sealed metal bucket to enlarge the lasting of the product.
Inox steel
It is available in shot/grit shape and wide range of sizes.
Hardness plays a critical role and influences finishing.
Benefit is a limited chemical interaction with the parts, this may be critical for further operations like electrochemical finishing.
Inox medias are consistently expensive compared with regular steel, so are chosen considering their impact on process cost. CM blasters with its own filtering system avoids to waste media still reusable inside the machine.
Waste can be really flammable so handling it with care it is not an option.
Ceramic
Ceramic is a kind of spherical shots identified by a letter B followed by some numbers; the higher the number the smaller the shots.
Features of ceramic is to be an hard material and yet very fragile, so this shots can provide good cleaning performances without spoiling the parts.
Consistency in shape and dimensions give high consistency during process, benefits paid while buying it because it is NOT cheap compared with regular steel.
To protect ceramic media during the process CM machine has a special kit to save media from being accidentally broken while flowing inside of the machine. It is always possible with a little spending to install this kit and convert an equipment made to run with steel to run with ceramic.
Ceramic waste is NOT reacting to fire, sparks, as metal dust usually is, so helps a lot to make the environment where it is performed safer compared with others kind of medias.
More than the fews media here introduced, there are literally a bunch with different materials, with different chemicals compositions, manufactured in different ways that is impossible to even think to write them down in such a simple list.
The Engineering Behind the Choice: Our Approach
The Engineering Behind the Choice: Our Consultancy Approach
Choosing a blasting media based solely on price-per-pound is the most common hidden drain on manufacturing margins. At CMblasterUS, we analyze the process through three technical lenses to ensure your choice is a strategic asset, not just a consumable:
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Kinetic Customization: We balance turbine velocity with the Specific Gravity of the media. Whether you need high-momentum steel for deep descaling or low-density aluminum/ceramics for delicate, thin-walled geometries, we engineer the impact energy to protect your part's structural integrity.
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The Hardness Differential: We evaluate the hardness ratio between the media and your specific workpiece. Our goal is to find the "Economic Sweet Spot"—the exact point where you achieve the required surface morphology (Ra/Rz) without causing unnecessary wear on your machine’s internal components.
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Metallurgical & Chemical Integrity: We prevent "invisible" failures. By selecting chemically inert media, we eliminate risks like ferrous contamination on stainless steel or surface energy imbalances that can lead to catastrophic delamination in subsequent coating or bonding processes.
Don’t just buy a commodity. Optimize your process.
The right media choice is a calculation of Total Cost of Ownership (TCO), factoring in purchase price, cycle times, disposal costs, and machine maintenance.
Are you looking to reduce your cost-per-part or solve a complex surface challenge? Are you struggling to source a specific media?