August 2001

Welcome to The CTMA Connector, a monthly newsletter designed to provide news and ideas about the Commercial Technologies for Maintenance Activities (CTMA) program. The CTMA program is a joint Department of Defense/National Center for Manufacturing Sciences (DoD/NCMS) effort promoting collaborative technology development between industry and the DoD maintenance and repair facilities. This newsletter highlights ongoing projects, serves as a forum for promoting new project ideas, and provides other news of interest to the program. Our goal is to stimulate your participation and solicit your input. Feel free to submit items for the newsletter as well as any suggestions to make it more useful.

Ongoing Project News

Rapid Prototyping

Last month, we reprinted an article about the Rapid Prototyping Technology Advancement (RPTA) Project that was published in the NAVSEA NEWS WIRE 01-20 (June 21, 2001).We neglected to recognize the contributions of all the project team members in this truly collaborative effort. In addition to the Pearl Harbor Naval Shipyard, other members include the Trident Refit Facility (Kings Bay, Georgia), United Technologies (Pratt & Whitney), Portsmouth Naval Shipyard, Raytheon, Norfolk Naval Shipyard (Philadelphia Detachment), Honeywell FM&T, Oklahoma City Air Logistics Center, Eastman Kodak, China Lake Naval Air Warfare Center, Baxter Healthcare, US Navy (Indian Head) and NASA. The RPTA program, now in its tenth year, is one of our largest and most successful collaborations. We thank each team member for a job well done

Next Generation Inspection System

The CTMA Next Generation Inspection Program (NGIS III) is off to a very fast start after a March kickoff. The Steering Group has toured the shop operations of the three end users involved: Solar Turbines Division of Caterpillar, and the Cherry Point and North Island Naval Aviation Depots. The group has also visited the two technology providers: Manufacturing Resources, Inc. (MRI), and Automated Precision, Inc. (API). The concept design was approved in July, and a final design review is scheduled for September 26. A critical review of the physical machine and software/operator interface was recently conducted with the Cherry Point operations people.

The industry consortium was organized to team with the Cherry Point Naval Aviation Depot to develop a production ready pilot exploiting the NGIS I & II technology and experience. NGIS I & II are both previously completed collaborative efforts by NCMS industrial members to develop new and improved technologies to support on-the-machine inspection. The projects targeted the need to provide dimensional measurement and on-the-fly scanning of surfaces capability at high speed, both in a CMM and on-machine environment, with multiple, interchangeable sensors.

Cherry Point operations people studied potential applications with best payoff and identified grinding and inspecting operations required for the repair of a family of parts including blisks, impellers, and individual compressor blades used on the T-64, T-58 and other similar technology engines. These components are critical to both engine performance and flight safety.

Airfoil surface damage, incurred in service and normally concentrated in the at the blade edge, is repaired by adding weld material to the damaged area and then hand grinding (blending the excess weld material) to achieve a precise surface. This operation currently is strictly a hand operation and relies heavily on operator skill. The close tolerances necessary under manual control often result in the removal of parent material, requiring a repeat of the weld, blend cycle and an occasional lost part if the parent metal is too deeply gouged. 

The project team is working to develop an automated cell to provide the multi-axis grinding and precise on-machine measuring capability to reduce cycle times and scrap risks associated with the current hand blending process. After field operation, the individual blades are not necessarily in nominal, or as designed, positions. The cell will have the capability to map the surface of each individual blade, generate an NC program to control the multi-axis grinding of the repair weld material to less than .005 of the final dimension, and perform and record the final inspection of the blade surface. Specific benefits targeted include an average 60 percent reduction at Cherry Point in the labor hours and cycle time for the sample parts for the benching and hand grinding from the current times, and the ability to rapidly acquire process data to enable tracking of process trends and quality history.

For more information, contact Bill Waddell, (231) 264-9774

Near-Dry Machining of Aluminum

In near-dry machining, the amount of cutting lubricant used is measured in milliliters per hour. This technology has been advanced through an NCMS collaborative effort to a point where there are clear signs of short-term success. The production machine tool is producing near-dry chips and accurate parts. With short-term issues resolved, the focus is now on the long-term issues -- tool wear, chip accumulation, maintenance and repair requirements, durability, reliability -- all issues that need to be addressed before adopting a new machining process. The team plans to collect data while processing 10,000 identical parts for each of two operating features as well as another 10,000 using conventional wet technology for comparison: a total of 30,000 parts.

The first run of 10,000 parts will explore minimum lubrication only. The second run will combine minimum lubrication with a unique vacuum system. In this second run, chips and vapor are captured inside a low pressure housing that shrouds each tool. The tool assemblies are placed in a typical tool carousel and automatically loaded into the spindle nose. The shroud functions like a hovercraft except the air flow is in the opposite direction. Chips and vapor are piped to a vacuum cleaner. The chips fall into a container and are sold at a premium price because of their dryness. This is the “CTMA Green Machine.”

The Green Machine is designed to allow conversion to a conventional high pressure coolant through-the-spindle system. The last set of 10,000 parts will be run in the wet configuration to provide direct data for calculating the net advantages of this Green Technology compared to wet technology. Work is scheduled for completion in December 2001 when one of the key questions is answered: What is the cost savings that can be credited to the near-dry technology?

As this element of the project is winding down, the next major element will be starting up. This aspect of the near-dry project is aimed at production -- specifically, increasing production by a factor of two or more. A second machine tool will be used with two special features. One feature is linear drives. Since the rapid traverse mode will be fast, and chip management should be good, the part-holding fixture is designed to clamp four parts: two up and two down. This will permit many machining operations to be executed before the machine is stopped for loading and unloading. In addition, multi-function tools have been designed and an attempt is being made to secure an automatic load/unload device within the time and cost constraints of the project. 

A meeting to expose and demonstrate these new technologies to Depot and CTMA personnel will be held at Machining Enterprises, Inc., Warren, Michigan, in September. If you are interested in attending this session, contact Jack McCabe at 734-995-4919.

Projects Seek Participants

Increasing Horsepower in Diesel Engines

The Army and the Marines estimate that a switch from D2 diesel fuel to JP-5 or JP-8 fuel will cause a 5 or 10 percent (respectively) reduction in horsepower in land-based diesel engines. This horsepower reduction will affect all families of diesel engines. Currently, the Army, the Marines and other branches of the military are still using their stocked D2 diesel fuel and have not yet exhausted their supplies. When the switch is made from D2 to JP-5 or JP-8, it is expected that some of the diesel engines will not meet dynamometer requirements and, therefore, will require extensive engine modifications to meet minimum specifications, or worse yet, become unusable. This reduction in horsepower has been confirmed by Red River, Albany, and an Army report.

Proposed Solution: The complexity of the diesel engine requires a multi-disciplinary team approach to address the interactions within the engine, develop experiments, solve the problems, integrate the solutions, and then deploy the results. In order to address this complex problem, it is necessary to concentrate on both the fuel system and the air system, and then the integration of the two systems. One solution to increasing horsepower is Extrude Hone’s Abrasive Flow Controlled Machining process. This process will produce optimal diesel engine fuel and air components -- designed by using dynamic flow simulation and analysis tools, and then machined by using an abrasive flow-controlled machining process that employs a visco-elastic non-Newtonian honing formulation. By passing an abrasive putty-like compound through the internal passages of ordinary cast and machined parts, the process will control the shape and smoothness of areas inside the part that normally cannot be reached with ordinary machine tools. By lowering the turbulence within the flow passages, the engine will breathe more easily, and both the mass flow rate and entry velocity of the air drawn into the combustion chamber will be increased. The result is a more complete and leaner fuel/air mixture and, consequently, a more efficient and cleaner combustion. The Abrasive Flow Controlled Machining process is used on both fuel and air components, such as inlet scoops, inlet ducts, intake manifolds, intake plenum chambers, cylinder heads, exhaust manifolds, turbochargers, superchargers, fuel injectors, fuel valves, needles, etc. This solution has applications for many military vehicles, such as: the High Mobility Multi-purpose Wheeled Vehicle (HMMVW), Commercially Based Tactical Truck (COMBATT), M60 Family of Vehicles, M551 Family of Vehicles, M728 Combat Engineering Vehicle, M88 Recovery Vehicle, Armored Vehicle Launched Bridge, M113 Family of Vehicles, M9 Bulldozer, the Bradley Fighting System, and many others.

Deliverables:  We anticipate the end result of this project will be two Abrasive Flow Controlled Machining systems deployed in the depots: one for the Army and one for the Marines. In the interim, this project will provide a job-shop service capability for processing diesel components (fuel and air) for the military maintenance depots and commercial companies. The job-shop service will be available for use by the maintenance depots as soon as project participants gain sufficient understanding in solving the under-horsepower problem. The Abrasive Flow Controlled Machining system will be available for procurement by the depots (and commercial entities) near the completion of the project and will include the manufacturing process parameters, tooling, and fixturing that is tailored for processing military and commercial diesel engine components.

Benefits: The primary benefit of this project is to increase the horsepower from various diesel engines that power land-based military vehicles to meet the requirements for the dynamometer and the vehicle. The project outcomes will provide both a job-shop service and two dedicated machine tools designed for processing diesel engine components. This will provide all the maintenance depots with the flexibility of either outsourcing the workload, procuring a machine tool for use within their maintenance complex, or a combination of outsourcing to develop the process then bring the workload back to the depots for production.

Quantifiable benefits are: 1) the number of underpowered diesel engines that will be able to pass dynamometer and vehicle testing, 2) the actual horsepower rating increase per individual engine, and 3) the increase in vehicle responsiveness as measured on the test track.

If you are interested in this proposed project effort, contact Chuck Ryan at 734-995-4905.

Calendar Items

Don't forget the 5th Annual DoD Maintenance Symposium & Exhibition "Meeting the Readiness Challenge Through Innovative Maintenance," October 29 - November 1 in Kansas City. The meeting agenda and registration can be found at http://register.ndia.org/interview/register.ndia?~Brochure~274

New Project Ideas (click on topics to see descriptions)

We appreciate your feedback. Please contact Chuck Ryan with suggestions or input on other topics that would be of interest to you in this newsletter. The CTMA Program is sponsored by the Department of Defense; the content of this newsletter does not necessarily reflect the position or policy of the government; no official endorsement should be inferred.