Monitoring and measuring quality of products and services is a key part of any QMS. But how can you be sure the equipment you’re using to monitor and measure is giving you consistent results? The answer lies in your calibration process.
Over time, any equipment used in product development and manufacturing can be prone to ‘drift’. Measuring equipment is no exception. Settings and configurations can slip because of mishandling, misuse, atmospheric changes, as well as natural wear and tear. A calibration process ensures you are regularly checking your equipment is delivering consistent and accurate results.
Why is calibration so important?
Even the tiniest change in tolerances can lead to products that don’t work properly. Where equipment is complex and safety-critical, such as medical devices or EV components, even micro-deviations can result in product failure, injury or death. Accurate measurements ensure products are being manufactured to exact specifications, so they will function exactly as intended.
What kind of equipment needs to be calibrated?
- R&D test & measuring equipment
- Production line test & measuring equipment
- Software used for the monitoring and measurement of requirements
Regular calibration is a requirement of ISO 13485 and ISO 9001
Where consistency and precision in quality assurance is an absolute requirement, your calibration regime must be formalised to avoid mistakes, waste and potential harm to users.
In ISO 13485 the regulation says
“The organization shall determine the monitoring and measurement to be undertaken and the monitoring and measuring equipment needed to provide evidence of conformity of product to determined requirements.
The organization shall document procedures to ensure that monitoring and measurement can be carried out and are carried out in a manner that is consistent with the monitoring and measurement requirements.”
Equipment calibration in ISO 9001
ISO 9001 speaks about the importance of documentation in measurement traceability
“When measurement traceability is a requirement or is considered by the organization to be an essential part of providing confidence in the validity of measurement results, measuring equipment shall be:
calibrated, or verified, or both, at specified intervals, or prior to use, against measurement standards traceable to international or national measurement standards; when no such standards exist, the basis used for calibration or verification shall be retained as documented information;”
What is the procedure for calibrating equipment?
With this in mind, you need a documented calibration process to:
- Identify which equipment needs calibration to ensure required quality in your end product.
- Determine measurements to be made and tolerances for each.
- Ensure calibration responsibilities (both internal and 3rd party) are well understood.
- Calibrate at required intervals and to national and international standards. (e.g. ILAB, NAMAS, NIST).
- Keep calibration records up-to-date and ready for audit.
- Adjust or repair instruments where appropriate.
How frequently should you calibrate your equipment?
Who is responsible for calibration?
The quality, lab, or production manager is typically responsible for calibration. But it is best to assign a single person to keep an overview, even if detailed activities are delegated. This will ensure you have an identified stakeholder responsible for meeting regulatory requirements and collating records.
For items used off-site (e.g. remote sites, contract manufacturers, etc) you need to ensure that responsibility for calibration is agreed - while gathering evidence that procedures are being followed.
Those who use the equipment are also responsible for checking that it is in calibration when they use it (this will act as a further safety net beyond regular checks).
What to do if something is found to be out of calibration?
- Advise the ‘owner’/user of that piece of equipment of the calibration failure.
- Analyse the potential consequences of the calibration fail, including whether the validity of measurements taken recently by that equipment has been compromised.
- Take corrective actions where necessary (e.g. re-test, add additional tests or inspections, do rework, recall products, advise customers, etc.)
9 tips to build an effective calibration process
1. Keep records in a single database
Keep a complete record of all equipment to be calibrated within a single database or equipment log. Look for a document management system (DMS) to compile and control this list.
2. Create documented SOPs
Provide documented SOPs for calibration that people can follow consistently - make them digital, graphical, and accessible for best results.
3. Define responsibilities
Ensure calibration is done by those with authority and competence to do so - ensure roles and responsibilities are clearly defined across your organisation.
4. Keep full calibration records
These can be paper or electronic e.g. scanned certificates, but a digital system is easier and less cumbersome to store and maintain. A dedicated document management system will also help you with version control and document integrity to ensure accuracy. Look for a system that allows you to create bespoke forms, to capture the unique flow of your calibration process.
5. Automate reminders
Have a process for flagging calibration due dates in advance - a digital and automated system of notifications is less likely to result in missed reminders and process failures.
6. Keep calibration status obvious
Have a way of easily, clearly and visually confirming the calibration status and next due date for each piece of equipment - at point of use. You can label machinery and use QR or reference codes to link users to records within your QMS for more information.
7. Mitigate risk of mistakes
Ensure the equipment cannot be adjusted, damaged or suffer from deterioration, without this being obvious. Create procedures to shut down and store equipment consistently when idle.
8. Incorporate visual checks
Have a regular visual ‘sweep’ through all areas of the business for equipment that is out of calibration or that will need it imminently, as well as damage or tampering.
9. Trigger non-conformance reports and CAPAs
Ensure you have a system to trigger non-conformance and corrective action processes when necessary. Use a DMS that can automate your workflows and reduce the risk of omissions and mistakes in your process.
Calibration is an essential part of quality management. The accuracy and consistency of calibration directly impact the quality of products produced. Quality managers must be able to accurately monitor the calibration of equipment in order to ensure that their products are consistently made with the highest degree of accuracy, efficiency, and reliability.
Calibrating equipment regularly also allows for potential problems to be identified quickly before they become a larger issue, allowing for greater control over cost, production standards, and customer satisfaction.