Surface finishing is a manufacturing process where the surface of a product is altered to achieve certain qualities. Surface finishing is done to enhance the product’s aesthetic or to make it more functional. It is also done to protect the product, making it resistant to wear or corrosion.
There are lots of surface finishing techniques, and more are being invented as technology advances. Surface blasting can be categorized based on the method used. Below is a broad classification of surface finishing techniques:
Mechanical:
This technique involves using physical force to alter the surface roughness of the product. An example of this type of finishing is grinding, polishing, buffing, sand blasting, and bead blasting.
Chemical:
This involves keeping the product in certain chemical solutions to trigger certain reactions, thereby altering the surface of the product. E.g., Pickling, Passivation, and etching, etc
Electrochemical:
This also involves chemical solutions, but with the use of electric current
Coating:
This process involves applying a layer or coat on the surface to enhance or protect it. A clear example of this is painting.
This article will focus on the Mechanical technique of surface finishing, specifically Bead blasting finishing. This article will fully describe what the process is all about, what advantage bead blasting has over other similar techniques like sand blasting, and its advantages and disadvantages
What is Bead Blasting Finishing?
This process involves shooting or projecting small spherical bead particles at high speed onto the surface of a material. Bead blasting, like every other surface finishing technique, acts to remove surface contaminants and imperfections. A bead blasting finish refers to a surface that has undergone the bead blasting treatment process. Bead blasting could be done through different media, like glass, plastic, or ceramic.
Unlike aluminum oxide, which is an extremely abrasive medium, bead blasting finishing is softer and more suitable for soft surfaces.
Bead Blasting Media
A wide range of beads are used for bead blasting, each with their unique characteristics and applications. Choosing the right blasting media is very important to achieving the desired bead blasting finish. Some common Bead blasting media are:
1. Glass bead blasting
Glass beads are versatile and are popularly used. This is due to their ability to produce a clean, bright, and uniform surface finish. They are made from lead-free soda-lime glass and can be reused several times. This makes them extremely cost-effective, and they are environmentally friendly.
They are ideal for decorative applications and light deburring, however, they may not be effective for extremely tough materials. The glass beads come in various sizes, ranging from (40-60) to (170-325) The former produces a lighter effect than the latter, which produces a coarser and rougher finish. The various sizes mean it can be adapted for different finishing needs.
2. Ceramic Beads
These are blasting media made from Zirconium oxide mixed with ceramics; they are denser and therefore longer-lasting than glass beads, although they look similar. Ceramic beads are suitable for hard surfaces, because they can be too aggressive.
Ceramic beads are non-reactive, which means they will not contaminate the surface they are blasted into. They generate low dust and are ideal for sensitive parts and materials like aerospace or medical tools
3. Plastic Beads
They are softer and ideal for cleaning plastic or sensitive components. Plastic beads are made from lightweight materials like polyester, acrylic melamine. They come in an angular or round shape and also in different sizes.
Plastic beads have a low impact during the blasting process, which makes them ideal for materials that are susceptible to scratching. They are also reusable, though they have a shorter lifespan than ceramic and glass beads.
Types of equipment Used in Bead Blasting Finish
The equipment needed for bead blasting is, of course, the blasting cabinet. The components of the cabinet are stated below, including their uses:
Cabinet body
The body is usually made from carbon steel and stainless steel. It is the main enclosure that houses the blasting operation.
Window
This is made from tempered glass or polycarbonate. It allows the blasting operator to view what is going on inside the cabinet while also protecting his face.
Safety Gloves
The gloves are made from rubber, they are fixed inside the cabinet and allow the operator to safely hold the material and the blasting gun while blasting is going on.
Nozzles
The nozzles help direct the stream of pressured air onto the surface being blasted. It controls the pattern, focus, and speed of the blast gun.
Blast gun
This mixes anddelivers the beads through the nozzle. It can be automated but it is often hand-operated. It has a metal body and is lined with ceramic. Sometimes the lining is made out of carbide
Hoses
The hose is made out of rubber, the rubber, however, is reinforced so that it can withstand the highly pressurised air. The hose is used to transport compressed air and the bead to the blast gun
Dust collector
The dust collector removes the dust from the cabinet during blasting, which keeps visibility for the operator. It is made out of steel
How Does Bead Blasting Work?
The bead blasting process uses specialized equipment like a bead blaster or a fully enclosed bead blaster cabinet. The bead blaster cabinet uses compressed air to accelerate the media. It also ensures the safety of the operator by providing an enclosed space for him to work. The cabinet is built in a way that prevents dust and contaminants from spreading into the air.
Below is a step-by-step process for the bead blasting finish
#1. Surface preparation
The operator needs to clean the surface of the material thoroughly, ensuring that oil, grease, or dirt is removed so that the blasting can work effectively. If there are areas that should not be blasted, they should be properly masked and protected.
#2. Selecting the right blasting media
As mentioned earlier, the beads could be ceramic, plastic, glass, or even more abrasive options like aluminium oxide. The operator needs to decide on which medium is most suitable. This is determined by the kind of material being worked on and the desired surface finish.
#3. Media Loading
The Fine beads are then loaded into the bead blaster cabinet.
#4. Compressed Air Activation and Surface Blasting
The right compressed air pressure is then selected together with the appropriate nozzle size and shape. A stream of high-pressure air pushes the media through the bead blaster gun. The beads strike the material’s surface, smoothing imperfections, cleaning residues, texturizing, and producing a matte appearance.
The blasting process must be well monitored to avoid overblasting and ensure even results
#5. Media Recovery and Recycling
Most systems collect the media for reuse and recycling. The dust, ,debris and other unwanted particles are, however, first filtered out.
#6. Final Cleaning and Inspection
The blasted material is then cleaned, usually by a blower, to remove any bead dust residue. It is then inspected to ensure consistency in the coverage and quality.
Application of Bead Blasting
Bead blasting is used across many industries. The following are the applications of bead blasting.
Surface Finishing
Bead blasting produces smooth, clean, and matte finishes on various materials. These materials include stainless steel, aluminum, brass, and titanium. It smooths out surface imperfections, providing a consistent texture across the material. This improves the functionality and aesthetics of the material.
Cleaning and Deburring
Bead blasting cleans rust, oxidation, carbon buildup, and other contaminants. It is also used to eliminate the small, leftover metal edges after any machining or cutting process.
Paint and Coating Preparation
Bead blasting helps with prepping a material for painting. It gives the surface of a material a slightly rough surface profile, which improves the adhesion of paint, powder coatings, and adhesives, ensuring that they last longer
Peening
This is the process of strengthening the surface of a material. It introduces compressed bead media to the surface of metals, enhancing fatigue strength and making it resistant to cracking
Electronics and Medical Device Manufacturing
The electronics and medical device manufacturing industry is one where cleanliness and precision are vital, bead blasting is therefore used for non-damaging, precision cleaning. It helps ensure that sensitive pieces of equipment are free from contamination.
Decorative and Aesthetic Finishing
For designers and manufacturers, bead blasting provides a consistent frosted, matte, or satin finish that enhances the visual appeal of products. It can be applied to metal, glass, acrylic, and other materials.
The table below gives an overview of key sectors and industries where bead blasting is used and how it’s applied.
Industry
Typical Use
Aerospace
Finishing titanium and aluminum parts, cleaning turbine blades, and aircraft fasteners.
Automotive
- Finishing engine parts, wheel trims, pistons, transmission cases, and brake components.
- Paint stripping for the restoration of vehicles.
- Strengthening suspension and performance parts.
Medical Devices
- Cleaning surgical tools and orthopedic implants.
- Creating non-reflective, hygienic surfaces on titanium tools.
- Preparing implants for coatings
Electronics
- Finishing smartphone casings, laptops
- Removing tiny burrs or residues from circuit boards and electronic housings.
- Cleaning without compromising dimensions or delicate parts.
Industrial Equipment
Valves, shafts, and hou
Jewelry and Assesory
- Creating a matte or satin finish on fine jewelry.
- Smoothing sharp edges or imperfections.
- Enhancing contrast in design elements
Advantages of Bead blasting finish
Bead Blasting is just one of several kinds of finishing, it has certain peculiar advantages over other forms of finishing. Below are a few of them
Effective surface cleaning
Bead blasting effectively cleans a material and removes imperfections without damaging it. Contaminants like rust, scale, and grease are easily cleaned off the surface of materials
Versatility
Bead blasting is more widely used than other forms of finishing. There are more media options to choose from than other forms. As mentioned earlier, media like plastic beads, ceramic beads, and glass beads provide the operator with options to choose from. This also means bead blasting can be used on a wide array of materials. e.g., stainless steel, aluminum, brass, and titanium.
The versatility of bead blasting also extends to the kinds of applications it can be put to. E.G. surface preparation, deburring, peening, and finishing.
Smooth, Uniform Finish
Bead blasting produces a uniform and consistent matte, satin, and smooth surface finish. It does this regardless of the material having a large area or complex geometries and dimensions. It also modifies the surface texture of a material to achieve roughness. This can improve the material’s appearance, grip, functionality, and paint adherence
Environmentally Friendly
Almost all of the bead media can be reused and recycled, although at varying numbers of time. The beads are also non-toxic, making them more environmentally safe than the other forms of finishing.
Property
Details
Surface Texture
Uniform, satin-matte finish
Material Integrity
No dimensional change
Cleaning Capability
Removes rust, grease, scale
Visual Uniformity
Consistent appearance across all surfaces
Grip and Adhesion
Improves paint adherence
Disadvantages of Bead blasting
Bead blasting also has some downsides. Some of them include:
Material Limitations
Bead blasting may be the best option when precision or sensitivity is required, but it is not ideal for harder surfaces with tough coatings or strong corrosion. More aggressive methods like sandblasting or grit blasting may be more suitable in such cases. If bead blasting will be used in this circumstance, it require that the process be done multiple times to, achieve the desired results.
Cost of equipment
It is extremely expensive to set up a bead blasting sytem. It may be cheaper if the use is not industrial or continous. A small bead blasting operation is time consuming and cannot be used for large scale prodcutions
Debril and Dust
Bead blasting generates a lot of dust and fine particles. This can become a huge hazard problem if it is not properly contained. The dust and debril could also contaminate the surface of the material, impacting on the final product. This could only be prevented if adequate time and care is taken to clean the material after the bead blasting process.
Maintenance and Care of Bead Blasted Surfaces
The unique loook and texture of a bead blasted finish requires that they be well maintained and cared for so that they last longer.
Here is how to effectively maintain and care for a bead blasted surface
Clean the surface regularly using mild detergents and soft cloths or brushes. While cleaning it is important to avoid harsh chemicals so as not to stain or dull the finish.
Avoid staining the surface with contaminants. Materials like salt, or oil can cause rust or discoloration. If by any chance the surface hets contaminated, ensure it is cleaned immediately. Metal surfaces like aluminium easily gets stained with fingerprints. This can be avoided by handling the materials with clean gloves
Apply protective coatings like sealants or wax
Bead blasted surfaces are suceptible to scratches which can be very conspicous, therefore avoid all kinds of abrasive contact with the material
If the material will not be in jse for a while, ensure it is stored in a dry place and well covered
Bead Blasting vs Sand Blasting: What is the Difference?
Sand blasting involves forcibly propelling a stream of sand against a surface under high pressure to clean, shape or roughen it. It is similar to bast blasting, only that the blast medium is sand. Other differences are displayed in the table below