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AFM delivers punch
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 This cutaway section of an intake manifold shows its condition before using the AFM process. |
Automakers and the racing industry are the latest beneficiaries of abrasive flow machining (AFM), a process discovered over 35 years ago to deburr and finish complex internal passageways on critical aircraft hydraulic and fuel system components. They are able to punch up horsepower and improve vehicle performance and component strength by using AFM to polish air channels in secondary intake ports and upper intake manifolds of cylinder heads.
Ford is using AFM on the 1998 2.5 L Contour SVT, which is the first volume production powerplant to use the technology. The racing industry has also discovered the advantages of the AFM process for machining components for Indy racing cars, Formula One cars, and CART and NASCAR Winston Cup racing cars.
Abrasive flow machining, developed by Extrude Hone, Irwin, PA, is an alternative to traditional machining for deburring, polishing, honing, and radiusing difficult-to-reach internal passageways. It is especially well suited for machining the latest generation of engines, which combine fuel injection and long sweeping manifold runners to deliver the necessary fuel and air mix to achieve optimum performance.
Using the AFM process on complex internal passageways within the intake manifold will create a surface finish lay that is parallel to airflow. The result is a dramatic increase in airflow velocity that contributes directly to significant horsepower gains. For example, the process was used on a manifold to smooth the cast finish and remove the core shift casting marks. A uniform surface finish was produced with airflow that was balanced from runner to runner resulting in a 25% increase in total cubic feet per minute (cfm).
A major European automotive manufacturer installed a system whereby castings can be polished directly from the foundry. It achieves processing production rates of 30 heads per hour. The system includes a rotary table that allows head loading and unloading while another is being processed. A 10µ´´ finish is produced from the original 120µ´´ to 150µ´´ finish. Emissions were reduced by 7%, power was increased by 6%, and mileage was increased by 5%.
Racing enthusiasts too, have utilized AFM on manifolds for the 5.0 L engine. Traditional methods involved cutting the manifold, polishing it, and then rewelding it. AFM eliminates cutting by forcing abrasive media through the entire manifold. Beside providing a polished wall on the runner, the total metal removal produces a larger cross-sectional area with greater air flow capacity. The amount of metal removal depends to a large extent on the original cast condition, with typical stock removal from 0.030´´ to 0.060´´. Applications range from polishing cylinder heads and intake manifolds to exhaust header sections as well as strengthening suspension components and brake rotors.
AFM is not limited to cylinder heads and intake manifolds. Any part that has a path where the abrasive medium can flow is a candidate for Extrude Hone modifications. Carburetors, water pumps, and exhaust manifolds are all suitable because they all have internal passages. Any component with an external surface that needs smoothing or reshaping can also be modified. Gears, automatic transmission stators, injector nozzles, superchargers, and turbocharger impellers can all be deburred, smoothed, or altered. The only requirement is that tooling must be built to support the component and direct the abrasive media to the desired areas to be abraded.
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| The abrasive media smoothes the internal passageways of the intake manifold, leading to improved airflow and increased horsepower. |
The 1998 Ford Contour SVT is the first volume production powerplant to use AFM. |
Central to AFM is the media made up of a semisolid polymer mixed with abrasives to gently and uniformly abrade areas where it is forced to flow. The viscosity of the media is formulated to provide a number of machining actions. For automotive applications, silicon carbide abrasive is typically used in sizes from 0.010´´ to 0.040´´.
The machine controls the media extrusion pressure, flow volume, and if desired, flow rate. It is made of two vertically opposed cylinders that extrude abrasive media back and forth through passages formed by the workpiece and tooling. Depending on the complexity of a given component and the percentage of improvement desired, the total volume of abrasive media is accurately monitored. Once the proper parameters are established for an application, they will remain constant from beginning to end.
For more information from Extrude Hone Corp, Irwin, PA, http://www.extrudehone.com
NASA urges use of composites
US industry is invited to use innovative and economical manufacturing techniques that produced composite materials for NASA's Reusable Space Vehicle, RSV at Marshall Space Flight Center (MSFC), Huntsville, AL. Computer-aided drawings (CAD) and specialized machinery, such as MSFC's automated fabrication systems, work precisely with many different types of material to produce strong, durable, and inexpensive materials without adding to its overall weight.
For more information contact the Marshall Space Flight Center at 800-872-6272.
On-line sensor pinpoints problems
A diagnostic system with on-line sensors that transmit warning signals to a central processing unit provides a predictive/maintenance program. The Ultrasonic Condition Alert (UCA) from UE Systems Inc, Elmsford, NY, automatically and continuously monitor the condition of bearings, test for valve leakage, trend cavitation, alert personnel of line blockage, and warn of electrical discharge in enclosed high voltage equipment. http://www.uesystems.com
Air gun provides cooling shop air
ARTX Ltd, Fairfield, OH, has developed an air gun that emits shop air for instant, on-demand, sub-zero spot cooling. The ARTX Model 60040 produces an air stream at 0 deg F or colder up to 2500 BTU/hr (630 Kcal/hr) of nontoxic, nonpolluting, residue-free cooling for applications such as dry machining, drilling, grinding, motor and tool cooling, and shrink fitting. The air gun uses no moving parts and creates no spark/explosion hazard or RF interference. http://www.palaver.com.artx
Coatingless process saves money
A joint effort between Argonne Nat'l Laboratory (800-627-2596), Argonne, IL, and AlliedSignal, Des Plaines, IL, found that the elimination of a time-intensive coating step in the manufacturing of anodized aluminum components will save at least $100,000/yr on the production of hard-anodized aluminum fuel control products. Additional savings will be realized on new products, for which the modified coating can be specified from the beginning of production.
Off-axis machining is simplified
The Optimum 2400 from Precitech Inc, Keene, NH, allows off-axis components to be produced through single-point diamond machining. An 80mm brass toroidal spectacle lens mold insert was machined on the Optimum 2400. The workholding fixture included provisions for integral balancing manufactured from 6061 aluminum. This provided the ability to machine four mold inserts simultaneously in an off-axis configuration. The position and radius of the offset diamond was established using an optical toolset station. http://www.precitech.com
Motion controller has it all
The PC46 motion controller on a single half-size ISA bus circuit board, developed by Oregon Micro Systems Inc, Beaverton, OR, can control up to six axes of step and direction, with pulse rates of up to 522,000 pulses/sec and support encoder signals of up to 4 MHz. Each axis has a separate command queue allowing the host computer to transfer a command string then proceed with other tasks, while the PC46 manages the motion process. htttp://www.omsmotion.com
