DISCOVER HOW FOAM-COATED ABRASIVES DELIVER A FLAWLESS FINISH
Ever wondered why foam coated abrasives offer superior performance over traditional sandpaper, especially for micro sanding tasks. Join us as we guide you through the essentials of foam-coated abrasives.
Let us examine the components of a foam-coated abrasive and then delve into the reasons behind their effectiveness.
Abrapower takes pride in collaborating with global leaders in product development to incorporate cutting-edge technologies and scientific advancements into the manufacturing of foam-coated abrasives. We are committed to staying abreast of material advancements and integrating them into our products. This strategy ensures that we consistently produce the world’s finest foam-coated abrasives, delivering superior quality and performance.
Foam coated abrasives are made up of 3 components
Foam
Glue
Grit
How it’s made
Abrapower sources specialist foams from a select group of industry-leading manufacturers to ensure optimal performance. By leveraging these partnerships, we concentrate our expertise on coating, enabling us to excel in our core capabilities.
We convert these foams in-house and have made significant investments in equipment to ensure precise sizes and consistent tolerances. This process is crucial for achieving optimal coating results.
The foam is coated with either a solvent-based or non-solvent adhesive, followed by a gravity fed flood-coating of grit to create a tightly coated surface area. Unlike open-coated paper, we maximize the surface space by utilizing the upward pressure from the foam, allowing the grit to maneuver across the surface. This aspect significantly enhances lifespan and prevents clogging.
Differences in solvent coating
Non-solvent does not require a top coat to lock grit in. Solvent coating was the original innovation and still preferred traditional tradesman. Non-solvent allows the same effective bond but ensures environmental safety.
Unlocking the Difference: Foam Coated Abrasives vs. Sandpaper
After years of testing, working with end users, and gaining valuable insights, sandpaper and foam-coated abrasives each serve their own unique functions. For finishing, foam abrasives are often preferable, while for removing surface material, sandpaper is generally more effective. Let’s face it: sanding is a laborious, messy, and time-consuming task, but it’s an essential step in surface finishing, whether you’re working on a cabinet door or a phone screen. A surface must be finished, which is essentially what scratch pattern you want to leave behind.
In the next section, we will highlight how this is achieved with both paper and foam-coated abrasives. Our intent is also to demonstrate how foam-coated abrasives will help achieve higher finishes with fewer steps, less cost, and less time, while also reducing the risk of mistakes in the final steps of surface finishing.
Cushioning Effect
The use of a foam surface vs paper allows pressure to be spread over a larger area, reducing the concentration of force at any single point. This makes foam abrasives less aggressive and more controlled, ideal for fine finishing.
Scratch Pattern Explained
The lines or marks left on a surface after it has been abraded.
Abrasive Particles: Scratch patterns are created when abrasive particles or tools move across a surface, removing material through mechanical action.
Contact Pressure: The depth and width of the scratches depend on the pressure applied during the scratching process.
Motion: The direction, speed, and type of motion (e.g., orbital, linear, rotational) influence the scratch pattern.
60 GRIT SANDPAPER RA RZ READING 10 x strokes
60 GRIT FOAM COATED RA RZ READING 10 x strokes
So how do we measure scratch pattern?
Profilometry
Surface profilometers measure the topography of the scratch pattern, providing quantitative data on scratch dimensions. The readings are quantified using the following formulas.
RA (Arithmetic Average Roughness)
Provides a single number that represents the overall roughness of a surface. Lower RaR_aRa values indicate a smoother surface, while higher values indicate a rougher surface.
RZ (Average Maximum Height)
Provides a measure of the extreme height differences on a surface, giving insight into the depth of scratches or other surface features. It is particularly useful when the surface has deep scratches or pits.
Now we understand scratch pattern let’s look at the standard conventions for measuring grit
You‘ve got the basic idea of how grit sizes for abrasives work, but there’s a bit more nuance to the standards used for measuring them. Here’s a clearer explanation:
When you buy sandpaper labeled 220 grit, it means the abrasive particles were sieved through a screen with 220 holes per inch.
If you buy a foam-coated abrasive labeled 220 grit, it will have been produced using 220 grit particles. However, due to the flexibility of the foam and how the grit is bonded, it will leave behind a different scratch pattern compared to sandpaper. What you will end up with is a scratch pattern equivalent to P1000-P1200.
Manufacturers of both sandpaper and foam-coated abrasives use the same standard sizing measures, such as CAMI, ANSI, and FEPA. Even though both types of abrasives use the same grit size, the finish from foam-coated abrasives tends to be finer due to the pressure distribution and bonding characteristics of the foam.
Micron measurement of grit particles with foam and paper comparison
Using foam-coated abrasives ensures more consistent results in micro sanding due to the unique properties of foam. Grit particles in abrasives are measured to determine their size, which directly impacts the surface finish. When micro sanding with traditional paper abrasives, the smallest particle size is typically chosen. In contrast, foam abrasives can achieve the same micro finish using larger particles because the foam disperses pressure, reducing surface loading. This efficiency speeds up the sanding process and delivers a smoother, more uniform finish.
Unlike paper abrasives, which quickly load with debris and become ineffective, foam abrasives can be gently tapped to release accumulated particles, allowing for extended use and prolonging their lifespan.
Diagram A demonstrates that the spaces between the grit particles allow surface dust and debris to fall away easily. Diagram B illustrates the problem when there are no spaces between the particles. Without these spaces, dust and debris get trapped, leading to particle buildup, commonly known as clogging.
Understanding the Grading System
Making sense of the grading system can often be confusing. Unlike sandpaper, where the grit size is the scratch pattern finish, foam coated abrasives use a different standard leaving the grit size no longer as applicable for the desired scratch pattern finish.
This can lead to variations between brands and products, causing uncertainty for users.
This table has standardized and simplified the grading system but lets look at how we got there.
Exploring Lifespan: Assessing Abrasive Grit Performance
To measure the lifespan of abrasive materials, whether paper or foam, the following test procedure is applied:
- Establish the initial cut rate.
- Continue sanding for fixed periods (e.g., every 5 minutes).
- Weigh the abrasive material after each period and record the weight.
- Calculate the amount of material removed during each period.
- Monitor performance to detect any decline in effectiveness after each period.
- Establish a threshold cut rate; typically, this is determined if the cut rate is 50% less than the initial cut rate.
- Inspect for visual signs of wear, such as a loaded surface or tears.
- Sum up the total effective usage time of the product.
- Calculate the total amount of material used over its entire lifespan.
HOW WE MEASURE CUT RATE
The cut rate is typically expressed as the amount of material removed per unit of time.
The measurement of material removed is done through weighing the object being sanded before sanding and then again afterwards.
HOW WE MEASURE LOAD RATE
Performance Testing
- Initial Abrasiveness: Test the sandpaper on a standardized material and measure the rate of material removal.
- Post-Use Abrasiveness: Repeat the test after the sandpaper has been used for a specific period.
- Comparison: Compare the rates of material removal to infer the degree of loading, as loaded sandpaper will typically remove material less efficiently.