Repeatability and reproducibility (R&R) testing is an excellent strategy for monitoring and proving the consistency of laboratory instrumentation and rheology testing machines. Regular R&R testing grants frequent insight into instrument performance, so quality personnel can catch and address potential issues quickly and minimize downtime or other losses.
What is R&R testing?
R&R testing is consistent, repetitive testing conducted at a prescribed interval in order to monitor the performance of a laboratory instrument. The exact same test is performed, using the exact same material, on a set schedule, and lab managers review the data after every test and over time to ensure consistent performance.
An R&R test has three major components:
Test Method
Regular R&R testing should use the same test spec every time to ensure consistent data. Common examples include ASTM D5289 and ISO 6502, both of which are designed for quality control.
Control Stock
R&R testing should be conducted with the same rubber compound every time. Many laboratories opt for a standard compound, such as:
- Peroxide cure EPDM rubber
- Alpha Technologies’ Alpha Quality Compound (AQC), a soapbox cure EPDM compound
Some laboratories make their own control stock, based on the compounds frequently tested in their machines. Ideally, this stock will be a compound the lab has been mixing for years and knows well, so operators know what results to expect and can spot anomalies easily.
Regardless of what material is chosen, control stock should be kept frozen to revent chemical reactions before testing. It is important to note, that even in the freezer most rubber compounds only have a shelf life of 6-24 months.
Schedule
R&R testing should be conducted at a prescribed, regular interval. Weekly testing is considered by many to be best practice. Conducting a weekly test is practical for most laboratories, giving frequent insight into instrument performance without erring on the side of excess. Some facilities may choose to test their instruments every two weeks or once a month, depending on their resources and needs.
Why conduct repeatability and reproducibility (R&R) testing?
There are three primary reasons to conduct regular R&R testing on laboratory and rheology instruments:
Prove an instrument’s capability.
Regular R&R testing creates a data record of an instrument’s compliance and performance. Depending on the context, this record can be used to demonstrate consistency for the sake of an audit, customer communications, internal quality assurance, or other purposes.
Reduce time spent investigating and addressing nonconformance issues.
When drift or inconsistency is detected in a laboratory instrument, the first step is to identify a general timeline of when the issue may have first occurred. This allows users to determine how much product may have been affected. If the instrument hasn’t undergone R&R testing in a few weeks or more, then any work completed since the last test must be investigated for possible issues. If the most recent test was less than a week ago, the investigation process will go much faster, and far fewer products will be at risk of going to waste.
Detect potential drift or other signs of decline in an older instrument.
Alpha Technologies lab instruments are designed for many years of reliable performance. However, aging is inevitable for any product that is used heavily. Regular R&R testing enables companies to spot patterns in their instrument’s performance that may signal the end of its service life. Early detection of aging yields a longer time horizon for planning and executing an upgrade to a newer instrument, which is beneficial for managing budgets and potential downtime.
When R&R testing reveals a drift.
When R&R testing does detect an anomaly in instrument performance, there are several steps or strategies to consider. Here is an example plan:
- Tag the instrument and take it out of service temporarily.
- Recalibrate the instrument.
- Call the instrument’s manufacturer to schedule a repair or, depending on the age of the machine, discuss an upgrade.
Once steps have been taken to address the drift, any material that has passed through the instrument since the last R&R test can be investigated for possible issues.
The Alpha Technologies Approach to R&R Testing
The team at Alpha Technologies understands that reliable, consistent performance of laboratory instruments is critical. We’ve designed our laboratory instruments and our service strategy around supporting R&R testing, so we can help our customers ensure consistency in their labs.
Alpha Technologies is proud to offer accredited calibration services based on popular ASTM and ISO quality assurance specifications. We also offer long-term planning support for customers who need to schedule instrument upgrades around budgetary considerations, downtime, and other variables.
Whether you’re seeking support for designing an R&R testing protocol or planning a large-scale laboratory upgrade, you can count on Alpha Technologies for support. To discuss your goals for your lab and your business, talk to a member of our team