Original Date: 05/19/1992
Revision Date: 01/18/2007

Close tolerance measurements are essential when using construction techniques like interference fits or press fits. Additionally, in situations where explosive gases must be contained and ram movement distances must be accurate and repeatable, the possibility of scratches or other possible damage must be avoided. CONAX Florida Corporation utilizes a non-contact method of measurement which has proven to be a highly accurate and reasonably priced procedure.

The method incorporates an Edmunds Trendsetter Column Gage system with ring gages (traceable to the National Institute of Standards and Technology) to perform 100% inspection of all bore and ram assemblies. The system forces air through precisely-sized orifices, and the pressure is calibrated using the minimum and maximum sized ring gages. The difference in pressure between the minimum and maximum is noted, and during the measurement, the actual pressure is presented on a digital bar graph. The air gage has an accuracy of ± .00005-inch. This system avoids using techniques such as calibrated pins which wear and can damage the component being measured if the pin has a burr. The technique also flags out-of-round conditions because the pressures will be inconsistent when the components are turned on the gage.

Initial cost of the air gage system was approximately $1,500 with each of the probe heads at $400 to $500. Other non-contact methods of measurement can cost more than 10 times that amount. CONAX Florida Corporation has developed a technique which fits their needs perfectly, and realized substantial cost savings in the process.

For more information see the Point of Contact for this survey.