Bead Blasting: Process, equipment, advantages, And Disadvantages.

What Is Bead Blasting?

Bead blasting is a process in which small spheres of glass or other abrasive material are blasted at high pressure against a surface.

Bead blasting is commonly used as a finishing step in manufacturing metal parts or to remove rust, paint, or other debris from metal surfaces. It can also be used to texturize plastic or glass surfaces.

Bead blasting is a type of abrasive blasting process in which media is projected onto a surface. The process is often performed using abrasive blast cabinets, which typically use compressed air to accelerate the media.

They also provide an enclosed space for the operator to work up close with parts and help avoid spreading dust or contaminants into the air. Round glass beads are widely used for bead blasting process.

Unlike other types of media blasting, which typically use angular-shaped media, bead blasting is associated with the use of spherical-shaped media.

When a piece of rounded media impacts a part’s surface, it produces a tiny dimple at the impact location.

As the process continues, thousands of these dimples consistently form over the surface. When using finer grades, the blasted surface will appear bright with a matte or satin-like texture due to how light reflects off the dimpled surface. Coarser beads can be used to produce a rougher but uniform surface.

How Does a Bead Blast Work?

Bead blasting can refer to the process of sandblasting or abrasive blasting. However, in most cases, it refers to projecting media in the form of a bead or sphere against a substrate such as stainless steel, aluminum, or any material that requires a surface conditioned via blasting.

Most abrasive blasting is done with jagged media and leaves a “coarser” surface finish. Bead blasting refers to the use of round spherical media that, when impacted against the surface of a part, will leave a more uniform finish caused by the sphere “dimpling” the surface.

This process is often used when a smooth uniform finish is required and the part must have a dull “satin” finish. The use of steel shot in this way is most often for tensile conditioning of the given substrate.

Bead blasting is the process most often used to achieve a surface finish that is both “rough” but consistent.

Fine glass bead blasting is commonly used on aluminum parts that need a “dull” or “satin” finish. The coarser glass bead gives a uniform “rough” finish while masking any imperfections in the substrate surface.

Other materials such as aluminum oxide, silica carbide, or garnet, even in their finest grits, will leave any substrate it impacts with a much darker “grayer” finish.

In contrast, glass bead blasting allows the substrate to maintain its base color resulting in a whiter or brighter finish.

Equipment Used for a Bead Blast Finish

The bead blasting process relies on specialized equipment to effectively propel the abrasive media onto the target surface. The following table details the equipment used.

Bead Blasting Cabinet: An enclosed chamber that contains the blasting media and workpiece, protecting the operator. It is typically made of durable materials like steel or aluminum.
Air Compressor: It generates the high-pressure air flow to propel the bead media at the desired velocity.
Bead Blaster Gloves: Protective equipment worn by the operator to safeguard their hands during the blasting process.
Bead Blaster Gun: A specialized nozzle or gun used to direct and control the flow of the bead media onto the target surface.

What are the advantages of bead blasting?

he bead blasting process leaves your CNC machined component with a smooth, clean, and aesthetically pleasing surface. A bead blast finish can clean corroded metal, remove cosmetic defects like textures and contaminants, and prepare a part for paint and other coatings.

Bead blasting is effective and versatile in that it can improve the appearance, performance, and durability of a wide range of materials and parts. The following are several of the advantages of bead blasting.

Effective surface cleaning. Bead blasting can effectively remove contaminants, rust, and other surface imperfections from a wide range of materials, leaving a clean and smooth surface finish.
Versatility. Bead blasting can be used on a variety of materials, including metals, plastics, and composites. It can also be used for different applications, such as surface preparation, deburring, and finishing.
Uniform surface finish. Bead blasting can produce a uniform surface finish across a large area, even on complex geometries.
Improved surface texture. Bead blasting can modify the surface texture of a material to achieve roughness or smoothness, such as a matte finish or a satin texture. This can improve the material’s appearance, grip, and functionality.
Reduced surface stress. Bead blasting can reduce surface stress and tension in materials, improving their overall durability.

What are the disadvantages of bead blasting?

Disadvantages of Bead Blasting:

More rigid surfaces require more time to bead blast.
Glass bead blasting doesn’t allow for paint adherence because it doesn’t leave a profile.
The bead blasting process would remove a small quantity of material from the part. It may not be suitable for applications that require strict tolerances.
The bead blasting process requires manual operation by a trained operator. The skill of your operator will have a significant impact on the final bead blasting outcome.

Applications of Bead Blasting

Manufacturers use bead blast finishes to achieve a uniform surface finish and improve part durability. In addition, bead blasting can be perfectly matched with various materials for various applications.

Functional applications of bead blasting include:

Peening: Peening is used to assist metals in withstanding fatigue and fracture.
Deburring: Deburring is smoothing the rough edges or ridges of metals.
Cosmetic Finishing: Cosmetic finishing refers to adding aesthetic features to parts.
Preparing for Other Finish: Preparing metal surfaces for powder-coating and painting.
Cleaning: Removing rust, paint, scale, and calcium deposits.
Polishing: Can be used to polish materials like stainless steel, aluminum, and cast iron.
Finishing: Can be used to create a matte finish on surfaces.

The industry’s applications of bead blasting include:

Aircraft parts before painting.
Guns and other military parts.
Aluminum parts for medical applications.
Automotive parts as preparation for adding brand-new paint.

Bead Blasting vs. Sand Blasting

While both bead blasting and sand blasting are similar in that they are types of media blasting techniques and sometimes share similar purposes, each is distinct with its advantages and disadvantages.

To help you better understand the differences and make the right choices for your project, we have outlined some of the critical aspects for each below.

Bead Blasting

In bead blasting, spherical-shaped media usually made of glass is accelerated to high speed towards the work surface.

The round shape of the media has a peening effect and creates small dimples on the surface.

The dimples act like miniature mirrors that scatter and reflect light towards the viewer, giving the part a bright and uniform satin-like appearance.

Pros

No free silica or silica dust
Gentle on materials
Does not affect part dimensions
Media is often highly re-usable for multiple cycles

Cons

Slow at removing paint and coatings
Does not etch surfaces for paint adherence
Slow to work with on harder materials

Sand Blasting

Sand blasting is a more traditional abrasive media blasting technique in which silica sand is propelled under high pressure towards the workpiece.

The irregular shape and sharpness of the sand particles can cut into and etch surfaces with ease. Due to high abrasion, sand blasting can be used to shape surfaces, smooth rough surfaces, and remove surface contaminants such as rust or corrosion.

While silica sand is still used in some cases, it is being moved away from due to potential health hazards, and other types of abrasive media are now commonly used in its place. Generally, abrasion blasted parts will have a duller appearance than those that are bead blasted.