Focus on Calibration Quality Not Cost
Some organizations treat calibration as nothing more than a regulatory requirement that they must follow that brings an additional cost to an organization’s bottom line. Subsequently, they have a haphazard system for managing their calibrated instruments and choose calibration providers only because they have the lowest prices. Other companies may initially compare calibration providers on the basis of their capabilities and quality but make their decisions solely on the price differences between them.
The true cost of calibration test and measurement instrument is a small cost compared to the impact that the instrument may have on an organization’s design and production processes. The calibration of measurement equipment is a critical part of the quality system in any manufacturing company. The organization must have confidence in the measurement results that they are collecting about their products or items they are inspecting.
Why Is Calibration Important?
Calibration is important to ensure that any measurement instrument being used is capable of measuring the required values and that those values are accurate and remain repeatable when measured over a length of time. Calibration will properly determine the performance abilities of the instrument with respect to the required specifications.
Measurement results are often used to make important decisions on production processes or crucial quality requirements. Decisions made based on erroneous data will likely have negative consequences for the business.
Many industries provide products or services where failure can be catastrophic. Measurement failures in industries such as aviation, automotive, medical devices and pharmaceutical products can have disastrous results for public safety. It is critically important for these industries to follow the proper manufacturer and regulatory guidelines in the calibration of their equipment.
Most measuring equipment will tend to drift when used over time. This can be caused by physical wear of the device, component variations for electronic devices, or changes due to the fluctuation of the environment in which it is being used.
Regular quality calibrations ensure that the instrument maintains its accuracy within the stated specifications and reduces the chance of the item being out-of-tolerance during calibration. Equipment that is not regularly calibrated or incorrectly calibrated creates numerous risks, questionable quality and even safety concerns
Costs of Poor Quality Calibrations
Good quality measurements are essential in all types of measurement processes. However, quality measurements are only achieved if properly calibrated instruments are used. Measurements made with poorly calibrated equipment can result in financial losses due to product re-inspection, rework, sorting and scrap. New engineering designs that are tested and validated with suspect equipment due to low-quality calibrations can require months of re-designs, software modifications or rebuilding of prototypes. There is a significant cost of downtime as personnel time and resources are being expended on resolving the issues that will create scheduling challenges for all other production functions.
If the product makes it into the marketplace, there could be even higher consequences such as recalls, personal injury, lawsuits and consumer dissatisfaction. Significant damage to a company’s reputation could occur resulting in the loss of potential business opportunities, dwindling corporate profits, and eventually employee layoffs.
Take for example the cost of the calibration of a torque wrench that is used for the tightening of the wheels or other components on a business jet. The calibration of the torque wrench only costs around $50, but if the wrench is not calibrated properly, damage to the wheel or landing structure of the aircraft could quickly add up into the thousands of dollars.
Another more extreme example in the aviation industry would be aircraft failure in flight. Improper calibration of a component can present an enormous risk in aircraft damage and in the loss of lives. A recent example is Lion Air Flight 610 that crashed shortly after takeoff in October of 2018 in Indonesia. The suspected improper calibration of one of the Angle of Attack (AOA) sensors is believed to have caused erroneous data to be sent to the Maneuvering Characteristics Augmentation System (MCAS) system. This caused the MCAS to activate multiple alerts and repeatedly produced flight control issues with the aircraft that the pilots could not properly manage. The flight crashed into the Java Sea killing 189 passengers and crew. 1
Unfortunately, the calibration providers that base their business decisions on finances instead of quality typically do not have a strong quality system to follow, do not use adequate procedures to calibrate the equipment to their full capabilities and lack the integrity and honesty required of their technicians and management. This results in a measuring instrument that has not been properly calibrated and that produces unreliable and inaccurate measurements.
Some calibration customers share instances where former calibration suppliers have knowingly arrived to perform onsite calibrations without the proper measurement standards present for the specific equipment being calibrated. They try to take advantage of the fact that most customers do not know how their equipment is calibrated and perform ‘hot-stamp’ or ‘lick’em and stick’em’ calibrations that do not test the equipment’s capabilities.
It has been shown that performing high-quality calibrations on measurement equipment is one of the most cost-effective ways to manage quality costs within an organization and reduce the risks associated with poorly functioning equipment. It is critical that organizations ensure that they are receiving high-quality calibrations at all times.
Maintaining a Quality Calibration Program
One way to ensure that poor quality calibration does not have an adverse effect on your measurement results is through the implementation of a quality calibration program within your organization to properly manage your calibrated equipment.
A quality calibration system will track instrument calibration due dates to ensure that the equipment does not go overdue for calibration. Tektronix makes managing your calibration easy with CalWeb. CalWeb is a cloud-based calibration management system that allows you to track equipment calibration due dates, store calibration certificates, and track equipment performance. Overdue equipment increases the chances that the equipment is out-of-tolerance when received for calibration, which may require time-consuming adjustments or repairs.
A proper calibration program will also assign and maintain equipment calibration intervals to ensure that the instrument is being calibrated at the proper interval to reduce costs due to calibration errors.
Adjustments to calibration intervals are one of the best tools an organization can use to manage the risk for their calibrated equipment. If an instrument is frequently out-of-tolerance when it is calibrated, reducing the calibration interval can help ensure that the unit remains within its specifications throughout its use. Equipment that is out-of-tolerance or OOT may require lengthy investigations and product re-inspections to ensure that the measurement error does not affect the specific measurements being made.
Likewise, if a piece of equipment is always in tolerance or is minimally used, the calibration interval may be lengthened as long as the risks are justified. Calibrations should typically be performed at least once per year at a minimum.
Selecting a Quality Calibration Provider
In order to receive quality calibration services, a competent calibration provider is necessary.
When selecting a calibration provider, it is critical to have confidence in the supplier’s abilities to calibrate the measuring equipment properly and to be competent in the services they provide.
There are two categories of calibration providers, accredited and non-accredited.
Non-accredited calibration laboratories are not required to have any type of formal quality system nor provide measurement data to their customers. They may not follow regulations that govern the technical aspects of the calibration laboratory to ensure that the proper training and methods are applied to the calibration process.
Accredited calibration laboratories are governed by the international standard ISO/IEC 17025 and are regularly audited by various recognized accreditation bodies to test the laboratory’s technical competence and that they follow a proven quality management system. They are guided by quality and integrity in all aspects of their job performance.
Accredited calibration providers can ensure that their measurement results are of high quality by providing:
- Traceability of Measurement Standards – The measurement standards used are traceable by providing an unbroken chain of comparisons to equipment calibrated at the highest national levels.
- Measurement Data – Customers are provided both ‘as-found’ and ‘as-left’ measurement data for their calibrations.
- Measurement Uncertainty Values - Measurement uncertainty is a combined measure of the error sources during a specific calibration. This value is important when analyzing the measurement results.
- Proper Environmental Conditions – Many calibrations require specific environmental conditions to achieve the stated accuracies. Accredited calibration laboratories monitor, control and report those conditions on the calibration certificate.
- Validated Calibration Procedures – Accredited laboratories use only the manufacturer’s procedures or properly validated procedures to provide a consistent calibration method for all equipment types.
Ideally, you would want to choose a calibration provider that has the capability to calibrate all or most of the equipment within your organization. Having a large number of calibration providers could lead to additional costs for shipping and extended turn-around times. In some cases, multiple calibration labs from the same company do not use the same standardized calibration procedures across their facilities.
Every accredited calibration supplier has a document called the ‘Scope of Accreditation’. The scope outlines the specific equipment types that can be calibrated and measurement details for which the laboratory is accredited to perform.
The Scope is an excellent resource for potential customers to easily see the various laboratory measurement capabilities for any particular calibration provider and compare and select the proper provider that meets their calibration and equipment requirements.