For many applications, the surface finish properties affect the appearance and functionality of the part. Abrasive blasting techniques are top finishing options, with bead blast finish being the most common.
The bead blast finish owes its popularity to the fact that it does not alter the dimension and shape of the part. Also, it is a safe and cost-effective way to produce high-quality polished surfaces. To make the most use of bead blasting, it is important to know how it works and its application.
In this article, we will extensively discuss bead blast surface finish, its use, and its various benefits. As a bonus, we dropped some tips you should follow to have the best bead blast finish.
What is Bead Blasting?
Bead blasting is a surface finishing process compatible with a wide range of materials. The bead blasting process propels rounded beads using pressurized air to strip or finish surfaces. This leaves a more uniform surface with little or no dimensional changes.
Furthermore, you can use a bead blast finish to modify the texture of glass or plastic surfaces. Removing surface impurities and cleaning out flaws or burrs off a surface has been made easy using these glass beads.
How Does Bead Blasting Work?
Bead blast surface finish works in ways similar to other sandblasting techniques. It uses a bead blaster to force glass beads against a part. The beads leave an impression as it comes in contact with the surface. The first bead blasting step involves loading the bead blaster with lead-free or soda-lime glass beads.
Thereafter, place the workpiece in the cabinet. Seal the cabinet and supply it with pressurized air. With your gloves, hold the bead blaster and the workpiece and start blasting.
Glass bead blasting leaves a range of surface impressions, from shiny and lustrous to a matte finish. The bead blasting surface roughness depends on the applied pressure and the shape and size of the glass beads.
As a rule, the finer the glass beads, the smoother the surface. However, this may not always be an advantage. Finer glass beads break easily and need frequent replacement. Additionally, a bead blast finish is ideal for delicate parts requiring a rough yet consistent surface.
Various Tools Used During the Bead Blasting Finish
The bead blasting cabinet, bead blasting gun, protective rubber gloves, and door make up the bead blasting machine.
Let’s take a look at each tool
Bead Blast Cabinets
The cabinet, just like the bead blast booth, provides a safe environment for blasting. You can refer to the cabinet as the backbone of the bead blasting system. The entire blasting process takes place in the cabinet.
The cabinet is important because it serves as a protective means for the workpiece and the operator. This makes it essential to consider the material the cabinet is made of. The construction material must be top-notch for quality assurance.
Manufacturers often use metals or plastics for the machine’s cabinet and doors. The most common metal used is steel for its strength and durability.
A steel cabinet can withstand the rigors of the blasting process. With less sturdy materials, there is an increased possibility that the legs will wobble as the weight it carries exceeds their capacity.
This wobbling movement slows down the entire process. Also, it may result in flaws in the final part. In addition to the construction material of the cabinet, it is important to look out for the following:
The Doors
A faulty side door poses a safety risk. A plastic door wears out with time and may let out the dust generated in the cabinet. The use of steel and other strong metals is a safer alternative. This is because sealing the steel door appropriately guarantees a successful blasting operation.
Screening Window
The window provides visibility of the entire blasting process. This tells you when to stop and take pauses. However, the particles have two major effects on the window. First, they may cause an originally transparent window to become opaque with time.
Also, it weakens the glass and increases the risk of breaking. Thus, it becomes imperative to mask the windows with a clear plastic sheet.
Bead Blasting Gloves
The gloves offer protection from abrasive particles. A single exposure of your bare hands to the flying particles may lead to tissue damage. Often, the gloves come attached to the blasting machine. To avoid various health risks, it is vital to the gloves and other PPEs appropriately.
Bead Blasting Gun
The bead blasting gun is an essential component. It is what propels the glass beads against the workpiece’s surface using compressed air. You will find these abrasive guns in various sizes, with most being handheld. You can control the gun using either a trigger or a pedal. However, the pedal control is ideal for more extended operations.
Glass beads
The glass beads are an essential component. There is no bead blast surface finish without the abrasive media. Soda-lime glass shaped into spheres serves as the abrasive media.
Glass bead is an economical way to finish a part. It is lightweight, so it moves freely to clean parts more. Compared to steel, glass is inert. This implies that it will not react with metal parts as it cleans.
Pros and Cons of Bead Blast Finish
Bead blasting offers several benefits as well as drawbacks. Let’s examine them in this section.
Pros
- Glass beads are cost-effective. You can choose to reuse the beads before replacing them.
- Bead blasting is a safe process and poses no significant health hazard. The glass beads do not generate silica dust during blasting.
- The beads are lightweight, so it does not alter the shape and function of a part.
- The use of glass beads is a chemically safe process because the glass is inert. Glass does not undergo any significant reaction with other metals. This makes bead blasting compatible with a wide range of materials.
- Bead blasting is an eco-friendly process.
Cons
- Bead blasting is a time-consuming process.
- Glass beads may not be suitable for hard metals.
- The cleaning effect doesn’t last long when compared to steel blasting.
- Glass beads do not create that rough surface paint that needs to adhere.
Applications of Bead Blasting Surface Finish
Manufacturers across many industries use bead blast finish for parts’ surfaces. Bead blasting maintains the structural integrity of many materials. The size of the bead depends on the intended application. Larger sizes strip rough metal surfaces quickly.
On the other hand, smaller sizes are more appropriate for delicate materials that require finer surface finishing. With glass bead blasting, you can do any of the following:
- Peening to modify the mechanical properties of a surface. The applied stress hardens the metal to prevent micro-cracks and breakages.
- Removal of light burrs and debris
- Sheen surface finishing that improves the cosmetic appearance of materials
- Surface preparation for further processes like painting or powder coating
- Polishing and removing surface deposits like rust and other forms of corrosion from metals
Many industries use bead blast finish, including:
- Automotive industry for car body steel plates and other functional parts.
- Medical industry for surgical devices and some dental implants.
- Rotor blades and engine components in the aerospace industry.
- Firearms and other important military applications.
Choosing the Suitable Blasting Media for Your Process
Based on the type of blasting operation, you can use glass beads, aluminum oxide, plastics, silicon carbide, steel grit, walnut shell, and corn cobs as the abrasive media. They serve as the basis for the difference between shot and grit blasting.
It is important to carefully consider the following before choosing a sandblasting media:
Material Hardness
The hardness of your workpiece directly influences the blasting media. When unsure, it is advisable to start with relatively soft ones like plastics. Softer abrasives result in a finer surface finish. You may consider harder steel grits or aluminum oxide to remove deposits of rust and paints.
Blasting Speed
The chosen media also influences the blasting rate. Though glass bead blasting provides a smooth and bright finish, it may be time-consuming. Glass beads have a gentle impact and may not be slower than other processes. In contrast, silicon carbide provides a more aggressive blasting action for tough materials.
Cost
Consider costing from two points of view—first, the initial cost of the media. Media like walnut shells and corn cobs are natural materials. Hence, they are cost-effective options for cleaning surfaces.
On the other hand, steel grits may require a high capital investment. However, steel grits are more economical in the long run. They do not break up, and you can use them multiple times for different applications.
Shape of the Media
The shape of an abrasive may be rounded, angular, or in between. Crushed glass is angular shaped with jagged edges. This makes the area of contact between the abrasive and surface low. However, they are ideal when cleaning old paint. Glass beads are round; thus, they create a well-defined bead-blasting surface roughness.
Kemal’s High-Quality Surface Finishing Services
There are many surface finishing operations; bead blast finish is just one. Surface finishing will help to remove surface flaws and improve the part’s aesthetics and function. Any mistake in finishing may affect the physical and mechanical properties of the part.
It is important to choose experts for high-quality finishing services. Kemal is the best available. We have provided solutions for everything from manufacturing to surface finishing for over two decades.
With our sophisticated technologies, we provide real-time updates on the finishing process. We can work with a wide range of materials with simple and complex features.
Our skilled operators will help you determine when to use a particular finishing operation and determine the most appropriate one for your part. Kemal is reliable, and our customer’s needs always come first. To get the best, upload your design and get instant quotes for free.
Practical Bead Blasting Tips for the Best Results
To make the best of the bead blasting process, it is important to know the understand the following:
Blasting Pressure
What happens when the glass comes in contact with hard materials? It breaks. This same principle applies when blasting using glass beads. Starting the process with low pressure (about 50PSI with a siphon blaster) is important.
However, you may decide to increase the pressure. It is important to note that higher pressure may shorten the life span of the beads. It is not economically reasonable to use very high pressure. Too high pressure may eventually crush the glass beads. Additionally, having glass embedded in a critical machine part may affect its functionality.
Remove Rust with Another Abrasive
Glass beads do not give that satisfactory cutting action. Paints, stains, and rust will not be removed effectively using glass beads. It is better to use glass beads as the finishing tool to achieve a great finish.
It is advisable to start with a cutting abrasive to clean all forms of corrosion and old paints. You can use silicon carbide, aluminum oxide, or crushed glass. Cost is the major determining factor, with glass beads being the most affordable.
Start with a Small Area
When unsure, it is best to start blasting just a small area. This will help save time and resources. Additionally, it builds your confidence as you clean larger areas.
Bead Blast Finish FAQs
Conclusion
Bead blast finish involves propelling rounded glass beads onto a surface at high pressure. The use of bead blasting is popular because it is compatible with many materials. Also, the process does not alter the shape and dimensions of a part.
What is bead blasting? What tools are important for bead blasting? How do you choose the right sandblasting media? We hope this article has answered all your questions. Feel free to contact us on anything abrasive blasting and other finishing options.
