Particle analysis is arguably one of the most crucial elements needed for reliable quality control, regardless of the industry you're in. It allows manufacturers to ensure their products meet the quality standards that their customers expect.
From test sieves to air jet sieves, there are several pieces of equipment that can be used to conduct particle analysis. Among all the different options, Dynamic Image Analysis Systems, such as the W.S. Tyler Computerized Particle Analyzer (CPA), stand out as the most efficient option for those who analyze more than ten samples a day.
So, how do you conduct particle analysis with a CPA?
Here at W.S. Tyler, we have over 140 years of particle analysis experience and strive to ensure you employ a reliable dynamic image analysis.
This article will provide a step-by-step guide on how to use a CPA unit to conduct particle analysis as well as some tips to keep your equipment in working order.
Preparing a Computerized Particle Analyzer
Before initializing your particle analysis process, there are a few steps you must take to ensure your equipment is ready for use.
First, you must make sure the software that controls your CPA (CPA Serv) has virtual sieve stacks set up for each type of material that is being analyzed. This will ensure your material is being tested in accordance with industry standards.
To explain this further, let’s say you produce plastic pellets and use different colors to indicate the different pellet configurations. Your CPA must have virtual sieve stacks preset for each pellet configuration in order to determine where each particle would stop in the stack.
With that, you must also ensure your CPA is using Standard Operating Procedures (SOP). These preset protocols will ensure your analysis is easy to run and produces accurate results that align with the time duration that, again, is needed to comply with industry standards.
Lastly, you’ll need to gather a representative sample as you would for any other particle analysis method, making sure to handle the sample material with care. To learn more about gathering and handling a reliable representative sample, refer to our article: How to Prepare a Sample for Particle Size Testing.
Performing Particle Analysis With a Computerized Particle Analyzer
Once you have ensured your software is using the proper presets and gathered a reliable representative sample, it's time to get started. Here are the steps you must take:
- Turn on your CPA unit. This must be done prior to launching the controlling software (CPA Serv); otherwise, the software will not properly detect your CPA unit.
- Once your CPA unit is powered on, you can then open CPA Serv on your computer.
- Lower the feeding funnel, known as the hopper, down to the feeder tray using the adjustment knob.
- Place your representative sample into the hopper.
- Using the hopper adjustment knob, raise the hopper two times higher than your largest particle. This will plan the material and prevent it from coming out all at once, skewing your results.
- Go into CPA Serv, select the material you are working with, and run your sample.
- Wait for the test to run in its entirety. The CPA will stop automatically when the camera detects there is no longer any material on the feeder tray.
- Save your results. To do so, you can either: create automated file naming conventions that save the results in a way that is easily identified by you and your staff, or you can save it manually after each test if you prefer.
- You can now take the sample material from the collection pan and either dispose of it or test it again if desired.
How Is the Sample Analyzed With a CPA?
The CPA employs a high-definition line scan camera to detect the shadow image of the particles as they pass an LED light. The results gained from this analysis are stored as a HAN file, which can then be viewed under any parameters.
Let’s refer back to the plastic pellet example.
If you run a sample of your white plastic pellets but want
to see the results as if they were run using the red pellet SOP,
you can apply the virtual sieve stack, time duration, or whatever parameter you want to the white pellet HAN file you just saved.
How Can You Verify Your Results?
As the CPA is not currently written into industry standards, you must incorporate some steps into your overall process to ensure you are gathering results that are accurate and comply with industry standards. The best way to do so is by keeping a physical stack of master sieves on hand.
These master sieves will be used to reference your CPA data.
For example, let’s say there's a standard that states that you must run a 50g sample of material for 10 mins on a RO-TAP®. You would do so, then take that same 50g sample and run it through your CPA to determine if you are getting the same results.
Maintaining Your CPA Unit
The CPA is fairly easy to manage and does not require a lot of maintenance. As with any piece of equipment, the best way to ensure it remains in tip-top shape is to clean it regularly.
You also want to avoid tampering with the presets unless necessary. Tampering with one element of the software can cause problems for the entire process and will require a trained technician to remote into your system to fix.
You also want to make sure you have clear file paths for all your save data for easy access. In addition, if you begin to notice a drop in computer performance, you can delete some save data that you no longer need to boost performance.
When it comes time to update your unit, your CPA specialist can remote into your system and ensure everything is working properly after the update.
Troubleshooting Your CPA
It goes without saying the Computerized Particle Analyzer provides a lot of beneficial qualities in terms of speeding up your process. While it may seem like the perfect solution, you may run into a situation in which you will need to use troubleshooting procedures to get your unit back in working condition.
For example, you may encounter an error that informs you that the CPA line scan camera cannot connect to the software. This is often an issue with the camera’s IP address and is easily fixed by a CPA specialist remoting into your system and changing the camera’s IP address.
You may also encounter some sort of com. port error after updating the software or connecting the CPA to a new computer. Again, this is easily fixed by a CPA specialist remoting into your system and altering the com. port configurations in the device settings or configuration file of the CPA.
Inconsistent Test Results
If you begin to notice your test results are inconsistent; this is an indicator that your camera needs to be re-calibrated. The best way to determine this is by placing the calibration frame on your unit to determine the pixel width in-between three bars on the frame.
When working properly, your CPA should read anywhere from 21 to 23 pixels in-between each bar. If you are getting an abnormal reading of 35 pixels, you will need to send your unit in for service, as this cannot be fixed remotely.
If you happen to run into an issue that is not listed above or need further assistance, simply reach out to your CPA specialist.
Become an Expert With Us
The Computerized Particle Analyzer (CPA) is the ideal particle analysis solution for those who test representative samples several times a day.
As it relies on computer software to function, the unit can be programmed to use presets based on the material being worked with, making your operation virtually seamless. To avoid all chances of error, it is important that you only alter these presets when necessary.
Other than a regular cleaning schedule, there is a limited amount of maintenance needed to keep your unit running for years to come. If your unit does run into some sort of error that prevents it from working properly, simply call your CPA specialist who is happy to assist you every step of the way.
With over 140 years of experience, W.S. Tyler has the know-how to assist you with your CPA unit or any other aspect of your particle analysis process.
Now that you have a better understanding of how to use a Computerized Particle Analyzer, please take a moment and review our Computerized Particle Analyzer product guide to see how the various CPA models benefit different industries.