Original Date: 10/07/2002
Revision Date: 01/18/2007
Best Practice : Certification to Program Standards
The National Aerospace and Defense Contractors Accreditation Program certification for nondestructive testing, welding, and brazing requires both documented procedures and process control. General Tool Company found that many of the requirements of the certification were already in place as a result of its efforts in obtaining ISO 9001 and AS 9000 certifications and has resulted in cost savings for the company.
General Tool Company (GTC) had previously completed certification to ISO 9001 and AS 9000. The decision to become certified to the National Aerospace and Defense Contractors Accreditation Program (NADCAP) in the areas of nondestructive testing (NDT), welding, and brazing was based on customer requirements. Through NADCAP, the Performance Review Institute accredits subcontractors and suppliers to aerospace and defense industry consensus standards.
GTC found that many of the requirements of NADCAP were already in place as a result of its efforts in obtaining ISO 9001 and AS 9000 certifications. However, certification for NADCAP introduced tighter process control for NDT as well as some improvements to process documentation. For example, an initial check of the dye penetrant batch on a daily basis replaced weekly checks, which limits any problems to just one day’s testing. Also it reduced costs as the penetrant batch was previously replaced at the end of each week; yet it is now used longer because tests indicated weekly replacement was unnecessary. A control/tracking matrix has now been implemented to track the calibration cycles of NDT equipment.
Another improvement from obtaining the NADCAP certification was realized in operation procedures. Operation procedures were the challenge for welding and brazing, due to few being in place and the variety of specifications and standards that had to be met. GTC brought in an outside expert to assist in writing and implementing the tighter process controls. GTC implemented new procedures and process documents for increased control of each NDT method. Standardizing practices for the assemblies that GTC builds on a repetitive basis reduces the possibility of unforeseen circumstances later in the manufacturing process.
There have been several benefits as a direct result of these improvements. GTC is now using approximately one less barrel of dye penetrant per year, a savings of approximately $1,500 per year. The tracking matrix allowed for increases in the calibration cycles, providing further cost savings. As a direct result of the standard practices being written for welding and assembly operations, the machining time for Penetration Housings has been reduced and overall efficiencies have improved (see Figure 2-5). The machinist noticed that the machining times for the housings were inconsistent; yet one welder’s product time has been 30 minutes less than the other welders. Further investigation found that the welder used a slightly different sequence for assembling and welding the part. The sequence used has been documented and is now the standard procedure, and has proven to increase the efficiency with which this part is built. GTC found that the reduction in time or elimination of source audits proves to be the biggest advantage for the NADCAP certification. This certification enhances quality all around. GTC not only meets the high standards of NADCAP, but also helps set them.
Figure 2-5. Machining Efficiency of Penetration Housings
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