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Robert Edmunds III of Edmunds GagesThe importance of choosing the right calibration lab
In this month's installment, Rob offers advice on selecting the right calibration lab for your company.
By: Robert Edmunds III
Edmunds Gages

 

 

Almost every day, my desk is besieged with literature from consulting firms promising quick and easy "Quality Accreditation." Typically, this sales literature is also accompanied by a quote from a satisfied customer who swears that his or her recent quality accreditation increased efficiency by X% and sales by X%.

Although the quality system acronyms may change (ISO 9000, ISO 9001, A2LA, NVLAP, etc.), the message is clear: You need these letters after your company's name or you'll be passed over by potential customers. The price, you ask? The hazing ritual known as "The Accreditation Process."

As many of you know, this process is a costly and almost necessary affair for those companies involved in the quality industry. Customers such as the Big Three automakers and their numerous second-tier suppliers require accreditation as a necessary step prior to conducting business. Right or wrong, this requirement is simply the state of affairs in a modern business atmosphere and the modern businessperson would do well to recognize this fact.

Though I am by no means an expert in the field of quality accreditation, suffice it to say, process documentation and standardization are considered two of the most holy commandments of the accreditation process. Additionally, the requirement of specific proficiency testing of key personnel at preset intervals is another hallmark of the modern quality invasion.

Increased process documentation, proficiency testing, and accreditation and re-accreditation fees cost money. Many smaller businesses – such as stand-alone metrology labs – have had no choice but to swallow a substantial cost-of-business increase or close up shop. The net affect has been to create a more streamlined business climate in the metrology world – the weak perish and the strong survive. This is not necessarily a bad thing, though. The labs that can afford the cost of accreditation usually are the ones that also can afford the other high fixed costs of running a climate-controlled metrology lab: specialized climate-control systems, proper metrology equipment, trained and qualified metrology technicians, etc. These labs generally will produce the most accurate measurements. It seems that the days of a mom-and-pop garage or basement operation are passing us by and Darwinism is the call of the day.

Assuming that you have survived the process and costs (time and money) and have attained quality accreditation, you still need to be accurate and prove it to your customers. Quality documentation and testing is helpful, but it's not the panacea many think it is.

Getting Down to Business: Choosing the Lab
When choosing a calibration lab for dimensional measurement, I recommend the following:

1. Choose an Accredited Lab.
Though an inconvenience for a lab that already produces a quality product, accreditation benefits the metrology consumer by ensuring a base level of organization and proficiency.

2. Check out the potential lab for its accreditations and accuracies.
Choosing an accredited lab is a good first step, but make sure you check to see exactly what the lab is accredited to perform and at what accuracy. Statements of Scope – a statement of what types of measurements the lab is accredited to perform – and Statements of Uncertainty – a mathematical derivation reflecting the lab's statement of confidence in a particular measurement – are vital to a thoughtful selection of metrology labs. Request and review these statements before making a decision – and don't be afraid to ask for supporting documentation.

3. Review the actual certifications you'll be receiving and consider your own particular audit trail needs.
The certification you receive should have all the relevant quality references as well as the required measurement result for your particular gage or tool. Depending upon your industry and given the fact that customers will vary, the necessity of certain information such as the lab's NIST traceability as well as the quality and calibration standard(s) to which the lab is accredited and to which the lab adheres are two critical pieces of information that must be considered.

4. Review the lab's quality manual and book of procedures.
It's imperative that you understand exactly how your gages or hand tools are being measured. As many of you know, there are many ways to skin a cat, but I'm sure if you talked to someone who performs this task, one way would be better than another. The same is true in a metrology lab. Make sure the metrology equipment is suited for the particular accuracies you require. A ring gage, for example, is best measured on an internal-external comparator using NIST-traceable gage blocks as the gaging standard. If the lab in question is using a jack-of-all-trades metrology machine where everything is adjustable or fails to perform the measurement in a temperature- and humidity-controlled environment – beware. This is the wrong lab.

5. Visit the lab and find out the experience levels of the technicians who will be performing measurements on your company's equipment.
Experience counts, especially when you're dealing in millionths. Make sure the lab technician who will be measuring your gages and tools has the skill and experience to accurately repeat the measurements. Get to know this person by name, because it's likely that, at some point, you'll need to resolve a correlation problem. A good working relationship with your calibration vendor can help eliminate the common knee-jerk response ("That person doesn't know how to measure.") to a contested reading. And the lab will be more willing to re-evaluate its methods and recheck contested gage measurements.

6. Perform a "Round Robin" and check the accuracy of the lab you're considering against other labs or NIST.
Though costly, I recommend sending one of your gages to NIST for calibration and then sending it to at least two commercial calibration labs to confirm the NIST readings. (Of course, don't reveal the NIST readings until after the other labs have submitted their results).

7. Check the financial status of the lab.
While it's not necessary to get a profit-and-loss statement from the owner, make sure the lab will be around for awhile. Changing calibration labs abruptly can disrupt a company's calibration history and, consequently, can affect the consistency of your company's quality methods. Even worse, if a lab goes bankrupt with your gages in their possession, you may not get them back. As many of you know, items such as gage blocks, specialty masters, optical comparators, and height gages are not inexpensive or short lead-time items. Losing them can create unnecessary and unanticipated financial and production problems.

8. Make sure the calibration lab you're considering maintains calibration records for as long as you need to have them for your auditors.
I recommend selecting a lab that can provide you with a computer disk copy of all relevant certifications. It's also a good idea to make sure the lab you select maintains a back-up copy in case the list is lost or destroyed at your facility. Because the certification is your evidence of a calibration performed, it makes sense to keep several copies of the information.

Finally, and perhaps more important, choose a lab you have confidence in. The more research you perform, the higher your confidence level should be when you make your decision. And the more comfortable you'll feel working with the lab.

About the Author

Rob Edmunds III has a Bachelor of Science degree in Mathematics and Business from Villanova University. Involved with many facets of the gaging industry, he also participates in national and regional industry associations. Currently vice president of Edmunds Gages, he can be reached during normal business hours at Edmunds Gages or via email at REdmundsIII@edmundsgages.com.

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