Countless industries throughout the world rely on material testing methodology to analyze the particles in their products. Knowing both the size and shape of your particles allows manufacturers to control product effectiveness and maintain customer satisfaction.
This is why all quality control programs should integrate reliable particle size analysis techniques, no matter what your operation looks like. It allows lab technicians and lab managers to obtain results that directly reflect the particle distribution throughout a given production line and make real-time adjustments when needed.
That said, you must have an understanding of all the different methods practiced today to ensure you are using one that best fits the needs of your particular operation. Once you determine which method is right for you, lab technicians must utilize best practices to avoid common errors and yield accurate and repeatable results.
What is Particle Size Analysis?
Particle size analysis is best defined as the analysis of dry, free-flowing materials to accurately identify both the size and shape of their individual particles. When properly integrated, it allows lab technicians and managers to ensure the particles in their products, whether produced in-house or purchased by a third-party, comply with their industry's quality standards.
For instance, particle analysis is used to calculate batch sizes during the plastic extrusion process. When production starts and the plastic needs to be melted, the calculated batch size helps determine the temperature needed to thoroughly melt the plastic and maximize throughput.
Regardless, failure to employ a dependable particle analysis can sometimes cause raw material to fault during production. This subsequently leads to early product failure or even recalls.
Why Is Particle Size Important to Material Testing? What is Particle Size Analysis?
Knowing the size of the particles in your material is essential, as it ultimately affects the performance of the end product once it reaches the hands of the consumer. That said, neglecting to identify the size of the particles in your material can create issues throughout your production line, potentially costing you thousands in revenue. In the fracking industry, for example, if you have too drastic of a particle size range, an irregular vacuum can be created. As a result, the fracture that is being mined for oil can slip and block oil from being drawn.
But in the pharmaceutical industry, particle size is a key factor that controls the effectiveness of the medications being produced. Specifically, the particle size affects the speed at which they are absorbed once ingested, dose uniformity, and their consistency. In other words, particle size analysis helps to ensure your material delivers the specifications, quality, and effectiveness that consumers expect.
How to Test Material using Particle Size Analysis?
To conduct an accurate and reliable particle analysis for material testing, there are three primary methods that you can choose from test sieve analysis, air jet sieve analysis, or dynamic image analysis.
Test Sieve Analysis
Test sieve analysis is the method in which material is tested using a stack of test sieves and a sieve shaker, such as the W.S. Tyler RO-TAP® Sieve Shaker. During a test sieve analysis, a representative sample of your material is placed on the top sieve in the stack and placed into the sieve shaker.
The sieve shaker then moves the sieve stack in an oscillating motion while also tapping the top of the stack. This series of motions cause the material to pass through the mesh openings of the test sieves until the mesh is too fine for the particle. Test sieve analysis is typically employed by labs seeking a method that is simple enough for any lab technician on staff to conduct yet accurate enough to adhere to industry standards. For a more in-depth guide on performing a test sieve analysis, review the article: How to Perform a Test Sieve Analysis (Preparation, Steps & Tips.
Air Jet Sieve Analysis
Air jet sieve analysis is a method that utilizes an air jet sieve, such as the Apline Air Jet Sieve e200|s, to create a vacuum that forces air through specialized test sieves. When the air is generated, the particles collide with its plexiglass lid and, if agglomerated, separate. This method is particularly useful when working with materials, such as powdered sugar and flour, which are known for becoming agglomerated while in storage.
Dynamic Image Analysis
Dynamic image analysis is the process in which lab technicians employ a Dynamic Image Analysis System, such as the W.S. Tyler Computerized Particle Analyzer, to calculate both the size and shape of particles as fine as 10 microns. This is done by feeding a vibrating tray that drops dry, non-agglomerated particles past a high-resolution line scan camera that processes 10,000 particles per second.
How Is Particle Size Measured?
Particle size measurements vary depending on which standard you must comply with. To put this into perspective, let's say you follow ASTM standards. Under ASTM guidelines, particle size is measured and determined by the mesh count of the sieve that hinders its movement throughout the remainder of the test sieve. Explaining this further, if you are working in the food industry and a grain particle stops at your 45 mesh sieve once material testing is complete, that grain would be considered a 45 mesh particle.
To that end, particles are also measured in inches, millimeters, and microns. It is best practice to use either the mesh count, length in millimeters, or micron size as the measurement unit for particles smaller than an inch. NOTE: Particles are generally within a size range of 20 microns to 4 inches when conducting a particle size analysis.
How To Prevent Material Contamination
When not handled properly, the representative sample of your material can become contaminated with foreign particles, such as biological matter, fibers, and metallic pieces. Failure to take the necessary steps to prevent material contamination often results in skewed particle analysis results. That said, there are three ways in which you can prevent material contamination: equipment examinations, staff training, and storage facility checks.
Equipment Examinations
Keeping your equipment in tip-top shape is the first step to preventing material contamination. This includes inspecting all tools and instruments used throughout the particle analysis operation, keeping mechanical parts well lubricated, and replacing worn or faulty components. You should also maintain a regular cleaning schedule to remove particles from past testing and any broken pieces of equipment, preventing further contamination.
Train Your Staff
The most common way material contamination occurs is from user error during the various testing methods. For this reason, it's highly recommended that you train your staff before material testing is conducted.
A well-trained lab technician will have the skills to do the following:
Secure Your Storage Facility
Material is often most vulnerable to contamination while being stored. This is because various debris often makes its way into storage areas. To keep your storage facility free of contaminants, you must check for any openings that mice and insects use to enter, water leaks, and air drafts. If you do identify any of these or any other vulnerabilities, they should be addressed promptly. With that, even if vulnerabilities can't be found after a thorough check, all material being stored should be adequately covered.
Conclusion
Particle analysis is a material testing method that involves lab technicians employing equipment to calculate the size and shape of the individual particles of the material being worked with. It allows manufacturers to gain real-time information about the particles on their production line and make changes, ensuring the end product meets customer expectations.
No matter what industry you work in, failure to implement particle analysis puts your operation at risk of product faults during the production phase. This can ultimately lead to product recalls. So, as you continue to fine-tune production, be sure to identify a particle size analysis method that is right for you and employ best practices to ensure your products are the best that they can be.
Candace Blaker is a product manager at W.S. Tyler that oversees all product lines that focus on particle size and characterization.