Metalworkers have many reasons to outsource metrology equipment calibration. Maybe the quality manager retired; given the skilled labor shortage, it’s going to be tough finding a replacement anytime soon. Perhaps production is going gangbusters, and the last thing anyone wants is to blow the upcoming ISO audit because of a noncompliant set of gage blocks or pins.

Or it could be that the shop’s collection of micrometers, bore gages, dial indicators and digital calipers may have grown in lockstep with the rest of the business—who has time to calibrate anything when the quality team is busy with first article inspections and supplier audits?

In-House vs. Subcontracting: Cost-Benefit Analysis for Manufacturing

Despite these and other obstacles, many shops still try to manage this onerous, time-consuming task in-house. But doing so can be penny-wise and dollar-foolish, says Steve Toll, chief revenue officer at Fox Valley Metrology, a service provider with 30 years of experience, hundreds of employees, and nine facilities across the United States.

“Outsourcing your calibration to a qualified provider is pretty inexpensive when you compare it to the fallout from being wrong,” he says. “You’re talking about scrapped parts, product recalls or even lawsuits—and that’s before you consider the downtime and lost credibility associated with such an event.”

Toll is quick to point out that the DIY approach rarely saves money, even for large, ISO-certified shops with teams of inspectors. If it were cheaper and more effective to do it in-house, this and other calibration service providers wouldn’t exist. “I’ve done hundreds of cost analyses with customers, and I’ve rarely seen the math work out in their favor,” Toll says.

Then there’s the workforce issue. As every shop owner or manager is keenly aware, hiring qualified workers isn’t getting any easier, and even if a shop can find a quality control person with the requisite skills and experience, Toll suggests that the company would be better served by assigning them to more value-added tasks than calibrating gages.

“There are companies like ours whose entire business is taking care of that maintenance for you,” he says. “From thread plugs, CMMs and height gages to torque wrenches, pressure gages and flow meters—pretty much any piece of measuring equipment—we’ll calibrate and certify it to a NIST-traceable standard. We can provide these services on-site, which means tools are taken out of service for a few minutes, or at one of our facilities, in which case our turnaround is three to five days.”

Regulatory Compliance: ASTM and Industry-Specific Calibration Standards

If the cost argument doesn’t convince you, adhering to industry standards might. As Toll explains, traceable calibration isn’t optional for any shop holding ISO 9001 certification.

That’s because Clause 7.1.5, “Monitoring and Measuring Resources,” mandates that organizations “ensure their monitoring and measuring equipment provides valid and reliable results by providing suitable resources and maintaining them for their intended purpose.”

The clause goes on to say: “Key requirements include calibrating or verifying equipment against traceable standards, maintaining documented information for ‘fitness for purpose,’ identifying equipment status, and protecting it from damage. If equipment is found unfit, the organization must assess past results and take appropriate action.”

Despite all this, some manufacturers still choose to perform their own checks. But as Toll cautions, the potential liability is scary. “If you’re calibrating in-house, that responsibility is entirely on you. When you outsource to an accredited lab, however, these concerns shift to your calibration partner, and you have documented traceability to back it up.”

Making matters even more challenging, different industries layer additional standards on top of ISO 9001. For instance, aerospace and defense contractors must also follow AS9100 and MIL-SPEC (military specifications) calibration procedures, while medical device and pharmaceutical manufacturers adhere to those found in Food and Drug Administration and ASTM International requirements.

ISO 17025 Accredited Calibration: Building Quality Management Systems

It’s Fox Valley’s job to keep its clients compliant across these various layers. However, the shop must first determine the appropriate calibration frequency for each item, document it and then adhere to the schedule. “We can’t tell a customer exactly how often to recalibrate a tool—that would be a conflict of interest,” Toll explains. “But we can advise on best practices for equipment use and storage, environmental controls and managing tool locations, so nothing slips through the cracks.”

Just as ISO 9001 governs quality systems in general, ISO 17025 is laser-focused on calibration and testing laboratories. Says Toll, “It’s uber-specific to companies that provide calibration services, dictating how we handle our records, manage our environment, train employees and verify vendor performance—everything. It’s basically the standard that allows us to exist in this space.”

With this in mind, a manufacturer doesn’t need to follow or become certified to ISO 17025, he adds—adhering to ISO 9001 and whatever industry-specific accreditation their customers ask for is plenty. But a calibration lab? ISO 17025 is its baseline, one that is continually tightening over time. “It doesn’t go backward. Every revision adds more specificity,” Toll notes. “Even so, it’s good for the industry. It proves there’s a third party monitoring us, that we’re actually doing what we say we’re doing.”

Calibration Interval Optimization: Preventive Maintenance Integration Strategies

But wait—if people like Toll won’t or shouldn’t advise shops on how often they should calibrate metrology equipment, what’s the correct interval? As with so much in manufacturing, this answer is, “It depends.”

The “every 12 months” rule of thumb is a good place to start, he suggests, noting that 95 percent of companies default to an annual cycle for basic equipment like micrometers and plug gages. On the other hand, high-use or mission-critical equipment might require it every three to six months, while large stationary systems like coordinate measuring machines (CMMs) can stretch to as long as five years.

Simply put, the “right interval” often comes down to the risk a company is willing to bear. “Compare the cost of calibration to the cost of being wrong,” Toll says. “Incorrect calibration of the torque wrench used on a vehicle assembly line, for example, could have serious legal consequences. In that case, I’d make sure someone checks it every few months. On the other hand, a caliper used occasionally for spot checks at the receiving dock—that’s low risk.”

Environmental factors also matter, he says. “A tool that lives in a clean lab behaves differently than one exposed to coolant and swarf all day, which is why I tell clients that the harsher the environment, the more often you should check the equipment used there.”

Once a shop does decide to outsource, the setup is straightforward. Assuming there’s an Excel spreadsheet or some type of database that lists the metrology assets, a Fox Valley Metrology technician can import it into their system, schedule the initial calibration, and they’re off and running. The company calibrates the equipment, generates new certificates and applies fresh calibration stickers before tools are returned, with each certificate listing the test points, tolerance and measurement uncertainty for that tool.

Traceability Management: National Standards Integration Methods

“Every device has an acceptance range, just like a part tolerance,” Toll explains. “We use the industry-accepted specification unless the manufacturer requires something tighter. Some customers even request we report ‘within uncertainty’ results, which show readings right on the edge.”

Setting aside the arguments outlined thus far, it’s the last one—traceability—that represents the lion’s share of what makes outsourcing worthwhile. Not only can the shop’s quality team sleep better knowing that all certifications are traceable back to NIST, but they can drill into each certificate to see the exact instruments used for calibration and, if needed, view the records of those instruments all the way up to a master artifact.

At the end of the day, calibration isn’t about who fills out the paperwork and applies the calibration stickers. It’s about confidence that every dimension, torque value or voltage reading means precisely what it says. And as Toll reiterates, saving a few bucks by doing it yourself can be an expensive mistake if you scrap out a batch of parts, or worse.

“Calibration might look like routine maintenance that anyone can do,” he says. “But it’s really risk management, and ultimately, the question is whether you want someone in your corner if there’s ever a problem.”

Learn more: Calibration: The Difference Between Rework and Repeatability