We’ve found that when customers compare dimensional inspection quotations, they do not take in consideration the laboratory environment. Laboratory environment plays a considerable role in the accuracy of your measurement data. When choosing the dimensional inspection laboratory to perform your inspections, you must take into account the 5 key factors of laboratory environment: Temperature/Humidity, Air Quality, Vibration, Equipment Condition, and Security.
The most important factor of the laboratory environment is temperature/humidity. Utilizing a standardized 68°F temperature enables you to effectively compare each laboratory on its capability to accurately measure your parts. All dimensional measurement accuracy formulas are based upon the ISO agreement and conformity to the long standing ISO and ANSI specifications, which can be defended and duplicated by others. The ultimate goal is to agree with NIST (National Institute of Standards and Technology). NIST controls their dimensional laboratory temperature to 68°F +/- 0.06° F.
Our laboratory at Bobier Metrology is a solid airlock enclosure utilizing 1µm HEPA filters; holding a constant temperature of 68°F +/- 1F and the humidity is at 40% +/- 10%. To our knowledge we are only one of four labs in the United States with this capability that perform GD&T inspections. You’ll have the confidence in knowing our results are precise & accurate.
Why don’t more laboratories hold their constant temperature at 68°F? Because of the COST!! As we all know, cost of electricity is always on the rise. Temperature control @ 68°F is a measurement accuracy and repeatability benefit, but a competitive disadvantage. To insure stability, this temperature commitment must be held 24 hours a day, 365 days per year. Depending on the construction of the lab enclosure and the size of the area (1600 sq. ft. for example) utility costs can vary from $3K – $4K per month.
All dimensional measurements should be taken in a clean pristine environment. When measurement accuracies are into the submicron levels, any loose dust particles can change the measurement data. If measurements are taken in a dusty environment for example, the measurements could vary 0.0003” per inch over the entire dimensional layout. This in turn could lead to your measurement data being off by many microns. Our laboratory at Bobier Metrology is a solid airlock enclosure utilizing 1µm HEPA filters; ensuring that our laboratory is a clean pristine environment suitable for measuring high-precision parts.
Almost all dimensional labs will provide annual calibration certification on their measurement equipment. Annual certifications are in good practice, but what if the machine drifts out of calibration? What guarantee do you have that your part is being accurately measured months after the calibration? Precision measurement machines are susceptible to many reasons causing the measurement data to vary. At Bobier, we calibrate our machines daily. We sent our in-house Class XXX Masters to NIST for ISO/IEC 17025 traceable certification data.
Additionally, our laboratory is security controlled. Parts are handled by laboratory trained personnel only, and are stored discreetly out of view of the public and/or visitors. Our lab is maintained by security code entry guaranteeing each inspection performed by Bobier Metrology is confidential.
So, if you send parts out for independent certification be sure and review the laboratory scope and specifications. Pay close attention to the uncertainty of measurement and temperature used in the calculations.
If a certification becomes just an opinion, then the courts will decide who is right and who is wrong. If this happens to your products, the money spent to clarify an opinion will pale when compared to the higher inspection costs (charges) of a 68°F laboratory.
The only way to achieve repeatability and accuracy over time is to control the temperature in the measurement environment.