Your Ultimate Guide to the Brushing Finish Process
The final stage in the manufacturing process is part finishing, which provides aesthetics and environmental protection. The process is used to reduce surface roughness on parts that must mate or seal beyond the capabilities of machining operations. Brushing finish exists in different forms and modified forms that suit a wide range of application flexibilities.
Interestingly, the brushing finish is also accompanied by other processes such as deburring, polishing, and rounding. With the combination of brushing finish with precision machining of parts, a well-designed product specification is assured. This article has rounded up every piece of information needed to understand brushing finish in detail. Read on to learn more about brushing finish.
What is Brush Finish?
A brushing finish involves many unidirectional lines that create a clean and consistent blanket over the surface of the metal. The process is performed at the front end of the manufacturing process. Brush finish is applied to either aluminum, stainless steel, or more, and can be combined with other decoration enhancements, including embossing, screen printing, and ElectraGraphics, to name but a few. Also, it can be used in a wide variety of products, but it’s prevalent in the home appliances, electronics, and automotive industries.
The brushing surface finish uses a wide variety of brushes to improve the surface quality to obtain the desired appearance. While these brushes are filamentary, they are distinguishable from bonded or coated abrasive products.
The Ideal Brushes for a Surface Finish –ToolTypes
In precision machining of parts, wide varieties of brushes are ideal for achieving a brushed metal finish. With these tools, anyone can achieve the desired surface finish effectively. Although they may be specific in their mode of action, they are sufficient to get the finishing job done. Here are two of the major brushes used in the CNC machining space:
√ Power Brushes
Power brushes are made out of carbon steel, natural and synthetic fibers, ferrous and non-ferrous wires. In the manufacturing industry, they can be used for a wide range of applications including, edge blending, substrate surface contamination, and polishing. Power brushes depending on horsepower, which is the amount of pressure exerted into the finish operation process.
Typically, power brushes vary in size, shape, and filament in terms of their built-up. This means that some brushes feature longer filaments which are applicable for moderate abrasive finishing. In contrast, those with shorter filaments are used for intensive processing or finishing. Some brushes vary in size, such as the diameter in which the largest diameter size gives the best and the most effective results.
√ Steel Wire Brushes
The standard brush for metal fabrication is the Steel wire brush. They are popularly known because they do not remove or tamper with the base material or change the part’s dimensions. Steel wire brushes clean surfaces with no sand particles colliding with the workpiece surface. Instead, wire tips are used to polish the part surface.
The mode of action of steel wire brushes functions such that it combines a high surface speed energy and hardened steel wire to ensure that brushes separate the surface contaminants from the substrate. Steel wire brushes come with varieties of configurations to fit different applications.
How to Effectively Brush a Finish
It is of high importance to brush a finish effectively to achieve an excellent end product. This section covers the fundamental rule and the procedure to brush a finish effectively.
The Fundamental Rule
When selecting a brush, some questions are needed to be answered. Two of the most important questions are:
What is the desired specification (in essence, edge break, cleaning, polishing, or deburring)?
What type of material is to be brushed?
If these two questions have been answered successfully, then the process will come out successfully. A steel wire brush is recommended if the goal is to deburr a cut stainless steel tube. Also, a carbon wire brush will deburr faster if considered. For any power tool, what is of paramount consideration is safety. After several cycles, the wires break and fall out due to fatigue which may puncture through clothing and skin. So, it is required to use leather gloves, a thick apron, work boots, and a full-face shield for offhand deburring.
Irrespective of the finish you are using, the brushing procedure is the same. The only significant differences are the time of operation, which may be less or more, and the type of brush to be used. The procedure below assumes you are brushing a stainless steel workpiece using a carefully automatic plating system like the Universal Plater.
Polish the workpieces’ surface using an abrasive metal polish
Wash or degrease the polished workpieces’ surface using Mother’s Mag and Aluminum polish or other combinations if required
If necessary, “electro clean” the workpiece
Re-set the polarity of the chrome handle
Depending on the job specification, you can use the nickel strike solution
Rinse thoroughly again
Gold Plate the part without delay
Commonly Brushed Materials
There are varieties of materials that can be brushed when it comes to brushing finish. While each material can be selective of brush, others may not be selective. The common brushed materials include:
leather plastics, and
Factors to Consider to Achieve a Flawless Brush Finish for Custom CNC Manufacturing
To achieve a flawless brush finish for custom CNC manufacturing, the following tips are helpful:
1. Use Quality Brushes
Heat-treated and oil-tempered wire brushes feature the best results. Also, there is variability in using different brushes; for example, stainless steel bushes help eliminate after-rust. Carbon steel brush features attributes like fatigue resistance and cutting action, which makes it more superior.
2. Determine the Appropriate Brush to Use
Different brushes have different applications. For example, a crimped wire brush is suited for parts prone to damages from the impact of knot brushes. Knot wire brushes are less flexible and are more aggressive.
3. Use the Required Speed for Each Operation
It is important to use the required safe speed when using brushing finish. This is said because brushes work similarly with the cutting tools. They worked effectively when operational speed and pressure exerted matched the demands of the finishing process.
4. Avoid Unidirectional Brushing
It is of effective brushing practice to reverse the direction of the brushing finish process periodically. This action will help users increase their efficiency and performance to achieve the desired results. A regular change in the rotational direction helps to take advantage of self-sharpening action.
5. Always Keep Brushes Clean
Brushes work to eliminate after-rust on workpieces. So, it is important to keep the brushes clean at all times to avoid contaminating the workpiece
Brushing Finish Pros and Cons
Brushing finish comes with a wide variety of pros and a few cons. Here are the pros and cons of brushing finish:
Eliminate slags and other defects that occur due to welding and other processes
Enhances the mechanical and physical properties of parts
Help to maintain tolerance & part specification
Improves adhesion to paints
Improves corrosion resistance
Improves the aesthetic properties of your part
Cleaning of brushed surfaces may be difficult
May cause damage to surfaces
The texture of the brush may limit a fluid’s ability to bead on the part’s surface.
The dense finish can result in visible brush marks
The following are the application of brushing finish:
√ Edge Blending
For edge blending, power brushes are suitable, especially for creating a rounded corner where two surfaces meet. With this process, you are assured of intact tolerance, reduced stress concentration, and reduced part fatigue with improvement in the life span of the part.
Brushing finish is used for deburring to remove burrs from other machine operations. This process can be done without further adding defects or leaving sharp edges on the part.
Brushing finish is also applicable in removing the film, dirt, weld slag, heat treatment scales, and pain from a part. For wet-cleaning operations, stainless steel brushes are suitable.
Brushing finishing can also create intramolecular bonds on non-ferrous metals, leather plastics, and rubber surfaces. Such surface achieves better adhesion when roughed with steel wire or power
The use of brushing finish offers a wide variety of benefits for your finished products. In addition, it provides a wide array of pros as well as applications. This ultimate guide provides every manufacturer the adequate information on brushing finish. When it comes to decision-making on a metal surface finish, manufacturing experts are always your best bet. RapidDone company is here to offer you the best finish solution services to help you achieve your short-term and long-term goals in manufacturing your products. Contact us today to request an instant quote.