Multiaxis laser system to produce the next generation of aerospace components
Multiaxis laser system to produce the next generation of aerospace components
Keywords Aerochem,Chemical milling, Components, Lasers
Improving product quality and accuracy, while reducing the costs of producing aircraft components is now a must for the survival of an aerospace manufacturer. In order to meet these challenges, Aerochem partnered with Lumonics to produce a significant advancement in one aspect of the chemical milling operation.
Chemical milling is a highly precise and specialized sequence of operations necessary in reducing the weight of aerospace components. This process is particularly appealing when trying to produce large, complex contoured skins which must be extremely strong but as light as possible. Parts like these make up the outer skins and inner structural components of various aircraft, helicopters, launch vehicles and jet engines.
The chemical milling process starts with coating the entire part with a chemical resistant coating in Aerochem's state-of-the-art masking solvent recovery system. The next step is to scribe (cut) the desired pattern into the maskant. This is followed by peeling the maskant from the cut areas to expose the bare metal. Next, these parts are submerged in a chemical milling solution: the exposed metal is etched away and areas protected by the maskant remain untouched. This results in an aerospace component with a pattern of thicker areas (masked sections) for optimal strength, surrounding thinner areas (etched areas) which reduce the weight. When the chemical milling process is completed, as much as 70 percent of the original part weight will be removed, while leaving original material thickness where strength is required.
The existing process requires a significant amount of painstaking, tedious and slow hand preparation in scribing the chem mill pattern into the maskant. It also requires the fabrication, use, movement, storage and maintenance of very large tools to define the pattern and hold the part in the proper shape.
With multiaxis laser control technology, the chem mill patterns can now be laser scribed with accuracy to a thousandth (±0.001in.) versus hand scribed tolerances (±0.015in.). The Laserdyne Multiaxis Laser System will also eliminate hundreds of cumbersome tools and templates for existing programmes. A flexible fixturing (holding)system from CNA is being integrated with the laser system. In addition, these systems will significantly reduce the costs and time to "tool up" for new programmes since no "hard tooling" will be required. Digital models of skin contour and chem mill pattern facilitate programming both the laser system and the flexible positioning system.
Now Aerochem will be scribing its skins automatically with the Laserdyne 890 BeamDirector multiaxis laser system. Aerochem, Inc. is the largest supplier of chemical milled aircraft components to aerospace giants such as Boeing, Northrop Grumman, McDonnell Douglas, Lockheed Martin and Bombardier.
Recently Aerochem installed a specially designed Lumonics Laserdyne 890 BeamDirector eight axis laser system with Extended "Y" (length) axis. The new extended "Y" axis provides the processing envelope that is required for parts the size of the current 747 skins as well as anticipated future sizes. Aerochem purchased this "first of its kind" system as part of their "life of program" 747 skin contract with Northrop Grumman Corporation.
The Laserdyne 890 BeamDirector system for Aerochem features a gantry style moving bridge on rails(8ft × 40ft × 3ft), with the laser carried on the bridge. The moving bridge design is the key to this system's large part size capability. In a single setup, without indexing or shuttling the workpiece, parts up to 40ft in length can be laser scribed. Longer panels can be processed on this system using indexing methods. The 890 BeamDirector motion control system is tuned for a constant mass the system's moving bridge. Because of this, the Laserdyne CNC control (System 94) performance is not influenced by workpiece weight or size. The capability for processing very large, massive workpieces without sacrificing dynamic performance is a significant benefit of the Extended "Y"axis 890 BeamDirector system.
Another novel feature of the Laserdyne 890 is the BeamDirector crash protection. This built-in feature disengages the BeamDirector at the slightest impact and "remembers" its position for quick restart.
With crash protection,Aerochem will have an extra margin of workpiece security to ensure that the fuselage skins are not damaged. The bottom line for Aerochem is maximized productivity.
Development of this specially designed 890 BeamDirector was an example of an extremely effective partnership between Aerochem and Lumonics. The design and manufacturing teams from both organizations exhibited strong commitment and flexibility in slightly more than 12 months from the initial concept discussions to project completion.
