Extending the physical life of aging aircraft particularly with the military is a rugged task balancing rising maintenance costs, shrinking inventories of parts and the increased usage being affixed military aircraft. Swapping out engines, avionics, landing gear and other components at certain usage points is common practice. With Conditioned Based Maintenance (CBM) now an integral part of maintenance procedures, extending structural life is a challenge in that balance of cost avoidance and increased flight reliability.

Coldworking fastener holes is a simple life enhancement procedure that strengthens metallic components by retarding crack growth around the hole. Coldworking holes expands the hole, producing a residual compressive stress zone around the hole. Fatigue life enhancement is generally increased by a factor of from two to seven. In addition to significant fatigue life enhancement, coldworking provides measurable value by reducing the need for unscheduled maintenance while increase aircraft reliability.

Coldworking processes (invented by Boeing) have been scientifically proven as a fatigue life enhancement tool. However DMI’s Cold Working Validation solution provides a scientifically proven validation tool to provide an electronic record that each hole had been properly cold worked at the prescribed expansion designated for each fastener hole.

DMI's CWV is a portable, handheld, battery powered instrument designed specifically to measure the amount of cold work (or cold expansion) applied to fastener holes. Fastener-hole cold working is an increasingly common maintenance practice used to extend component life. What has been elusive in this process is validating that each hole was cold worked and that each cold worked hole was cold worked properly. DMI has developed a field ready tool with validated accuracy of 2/10,000ths of an inch. Immediate cost saving can be retrieved and documented by way of the elimination of cumbersome manual data retrieval and record keeping. For the very first time, fatigue life enhancement can now be provided based on coldworkings’ scientifically documented value and as such significant cost avoidance can be implemented due to accurate validation data.

DMI's CWV generates a detailed record of pre and post coldworked fastner holes which drives operational and engineering analysis of the workflow.

• Scientifically proven measurement system
• Field and maintainer friendly
• Measurable return-on-investment