When Facing Calibration There are Many Factors to Consider to Ensure Accurate, Reliable and Cost-Effective Servicing.

Nothing lasts forever, and so it is with gage accuracy and repeatability. Drop them enough; subject them to the rigors of manufacturing plants, or mar their measuring surface from abrasive contact — sooner or later gages need to be re-calibrated. Most quality conscious machinists and inspectors will agree on this, but how gages get calibrated, who calibrates them and where it is performed is a subject worthy of discussion.

Aside from the obvious quality pitfalls of using gages that aren't accurate, avoiding calibration can become very costly in other ways as well. For example, decreased productivity, or losing contracts due to lack of measuring compliance or certification are factors few can afford to risk in today's extremely competitive environment.

With high stakes such as these, one might assume that proper resources, methods and budgets are commonly deployed for calibration programs. On the contrary, it is fairly typical for users to make the mistake of attempting to calibrate their own gages using the wrong methods and/ or tools for perceived savings and convenience.

Some people think calibrating is a quick and simple fix. They may grab a few gage blocks, perform a hasty inspection using crude measurement principles and assume they're done. What they don't take into account is record keeping, training, follow-up, maintenance of master standards, environment, official procedures and other issues that effect proper calibration. People are often misinformed on what tools and methods are acceptable for performing calibration. 

In-house calibration, especially comprehensive, established programs in large companies that have thousands of gages, can be a very effective approach for the right application. However, outsourcing calibration is perhaps the most prudent method for many companies for a variety of reasons, among the most prominent being cost and competence.

Outsourcing Can Reduce Cost & Increase Reliability

If you are committed to proper calibration, outsourcing can save money and headaches. After factoring in the cost of hiring qualified technicians, buying sophisticated equipment, training and record keeping, all of which is essential to guarantee certifiable results, it is surely no small expense to do it yourself.

Break-even expenses for those brave enough (or large-scale enough) to attempt calibration in-house can cost well into the thousands. At minimum, it can cost around $250,000.00 for initial ramp-up with equipment, depending on your application. Then probably another $125,000.00 for a few technicians. And that's not including other issues like taking up valuable manufacturing space to build a climate-controlled lab. Altogether it could easily cost more than $100,000.00 annually to operate an in-house lab. In other words, unless you have a tremendous number of gages, it is cost prohibitive to set-up an in-house calibration operation.

Standard Problems, Quality Solutions

Consider the following example on how expensive it can be to calibrate standard gage blocks in- house. If you wanted to achieve a low level of uncertainty, such as +/- 2 or 3 millionths of an inch, this would require sending a master set of blocks directly to N.I.S.T. The cost could be astronomical; up to $40,000.00 for a full set of inch and metric masters. The sensible alternative would be to send your blocks to an accredited laboratory that has already paid the expense to have their master blocks calibrated through N.I.S.T. The savings can be significant. At only $4.00 to $ 7.00 per block for a commercial laboratory, calibration costs may surprise you.  Especially when it can cost $130.00 per block when calibrated by N.I.S.T.

Cost isn't the only advantage when outsourcing. Other critical issues, such as standards, also come into view. Are you an ISO/ IEC 17025 accredited source? An appropriately accredited lab will ensure that you meet compliance with today's standards. Consider also that today's standard may change tomorrow. Keeping up with continually changing requirements is difficult at best for those who are unfamiliar with the process.

Other obvious benefits are improved quality, reliability and convenience.  If you are consistently using a dedicated, independent source, your quality will increase. Plus, larger companies benefit by standardizing their gage calibration and record keeping all within one source.

Who Will Do What?

Before gages are outsourced for calibration, the best advice is to be careful. There are several options, based on your needs. Depending on the work required, you could send the gage back to the manufacturer or maybe to a lab. Always check to see if the manufacturer has an established repair and calibration program with thorough procedures. 

If you have gages from different manufacturers like most companies, it becomes difficult trying to send tools to various sources. Be sure they can handle all major brands of gages in one location.

Other risks are the type of lab. You may find a good source, perhaps even a specialist in certain product areas, but beware of size. It is not uncommon to see smaller one or two person outfits close up shop. Also, look for adequate equipment, experience and ability to service effectively.

A Backup Plan

Of course there are a few downsides to outsourcing. When your gages leave the plant, you are without a means to measure if you don't have a backup plan. You also need to schedule accordingly or you'll risk interrupted production. Although it's rare, a gage can even be lost in transit, or if not packaged properly, damaged. But the alternatives are costly and/ or difficult with questionable results. Ultimately the question should be asked, 'what type of value do you put on quality and customer satisfaction?' Words we would all do well to live by.