Using Calibration Verification to Boost Leak Test Reliability, Efficiency
A new leak test system on your line needs to be calibrated to ensure it is providing accurate pass/fail results. You also need to recalibrate when anything in your process or equipment changes to ensure accuracy, whether you change out a test line, you start using different materials, you add different machining to a part process, etc.
Recalibration is also recommended on a regular basis to ensure the continued accuracy of your testing. Depending on your instruments and the parts being tested, some manufacturers will recalibrate annually, or on a more frequent basis, such as monthly, weekly, or even with every operator shift change.
A more frequent recalibration schedule will better ensure your instruments are delivering accurate results, reducing risk of costly and time-consuming scrap and rework costs due to incorrectly passed or failed parts. However, running a full recalibration process at such a frequent rate might not be ideal for your manufacturing process. First, not everyone on your line may be trained in recalibration processes. Second, it can be time-consuming, causing bottlenecks and inefficiencies on the line if done incorrectly.
Incorporating calibration verification processes into your line can deliver the benefits of consistent accuracy without the potential problems caused by a learning curve and time-consuming processes of a full recalibration cycle.
Conducting calibration verification on your leak tester
After your test has gone through a full calibration process (we recommend a two-point calibration method for the most accurate readings), you can quickly ensure your test is running accurately on a more frequent basis using calibration verification in the interim before your next set recalibration cycle.To conduct calibration verification, you need a known good part separate from your master part. With this good part, you can do one of two things; you can integrate a leak standard into that part (drill a hole and screw it into a threaded port), or you can plug it into an external connection.
The reason we recommend using a calibrated leak other than a random rejected leaking part from your process is because leaking parts aren’t repeatable like a leak standard will be. If it’s not possible to build the leak into a product, you could consider placing a leak standard connection point into your test line (this can either be an actuated valve or a checked quick connect fitting). If it is a manual connection point, make sure it is where you could easily snap in a secondary leak standard to verify the system calibration measurement.
You’ll then run your verification with your known good part by first plugging in a leak standard or external connection 10-20% above the reject rate. That would produce a red light and give you a measurement that should read close to the leak standard measurement to verify your calibration accuracy. Then you’ll plug in a leak standard or external connection that is 10-20% less than your reject rate. That would produce a green light and again allow you to verify the flow rate reading with that of the leak standard.
Using the calibration verification method after a full recalibration cycle
Though calibration verification can be used as a quick interim check between full calibration cycles in your schedule, it is also recommended to verify your calibration after a full recalibration. Problems like a thermal event, a new leak in your master part, or worn seals could occur and you could be accidentally setting up a calibration that is not correct. That’s why it is always a good idea to verify your calibration with a leak standard control to verify if your calibration is correct or off.
CTS certified leak standards for calibration verification
Cincinnati Test Systems provides the products, services, and expertise to ensure you are always confident in the reliability and repeatability of your leak test. CTS provides a wide selection of certified air flow and tracer gas leak standards. Our calibrated leak orifice units are precision-manufactured to match your unique flow and pressure requirements. All leak standard calibration is performed in-house in our A2LA accredited and ISO 17025 certified lab. We also provide a NIST-traceable calibration certificate with every leak standard.
Our certified leak standards mount into master calibration parts or plug into test lines and manifolds for calibration processes. CTS supplies a full selection of different leak standard fittings to accommodate various threaded applications and leak test instrument suppliers mated fittings. We also perform instrument calibration and leak master recertification services in our certified lab for continued optimal testing.
Need help with calibration on your line? Our leak test specialists would be happy to assist you to ensure an accurate test every time.
As a reminder, we will replace your CTS leak standards at no additional cost if found to be out of tolerance during a recertification order with us.
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