Sometimes you just don't realize how much better new technology is until you try it. Machine technicians at NASA Langley Research Center in Hampton, VA, had held onto two 1985 model NC lathe well beyond their technological prime. Regardless of how creative the team was in compensating for any shortfalls over time, an upgrade was imminent. With the purchase of a new multifunction machining center and CAD/CAM product, now their creativity knows no bounds, literally.
Most of the research center's parts are wind tunnel model components produced for the aerospace exploration program - rocket-type models in preparation for the changeover from the shuttle to rocket program. The data from the models will be gathered and compared with a variety of calculations. "They are long bodies of revolution with complex milling features and requiring 5-axis work such as drilling obscure angled holes," explains Deputy Product Manager, Jeff Brady. "A lot of what we do is completing what we call 'door-knob shapes' with all sorts of different contours."
Because of the extensive design time and frequent requirement changes for their part needs, the average project takes approximately a year to complete, yet Brady's team may only have up to two months to make the hardware. With parts ranging from 2" to 14" in diameter and 4" to 60" long, some parts are produced in different stages and assembled or connected to make a scale model for exploration and testing purposes.
A lot of time had been spent moving between lathes and milling machines several times to meet their part requirements. Upgrading to the new Okuma Multus B400, now practically all of the setups can be performed on the one machine, reducing a lot of setup time and making it easier to meet tight delivery schedules.
A lot of time had been spent moving between lathes and milling machines several times to meet part requirements. After upgrading to the Okuma Multus B400, practically all of the setups can be performed on the one machine, reducing setup time and making it easier to meet tight delivery schedules.
The first rather complex piece was a model support structure that will support the model in the wind tunnel. It took four weeks to produce, and resembles a cone or funnel - approximately 3" to 12" in diameter and 20" long. A lot of turning was required for the primary cone shape followed by milling of the pockets and then cutting out the interior of the part. Next, a diamond-shaped slot was cut on the back end, and putting some precision holes into the structure. The last set-up was for precision-type lapped holes to mate with some balance sleeves.
The piece was so big conventionally, it would have been manually rotated several different times, either 180° or 90°, then to put holes into it, and rotate it at 30° intervals. "Not having to orient and make multiple setups saved us an incredible amount of time," Brady explains. "It was a very good test-part for the machine - to see the machine's capability and that piece would probably would have taken six or seven setups on a conventional machine and we did it all within two setups."
The part took four weeks to complete because the new post was also being resolved during this time. However, Brady believes that time will be reduced by about 25% once the operator learns all of the bells and whistles of the Multus, its B and Y axis, plus it's new THINCOSP control. "Advancing to the Multus from the older/simpler technology left a lot to learn and adapt to, the technician has had to catch up a bit."
To develop the new Okuma Multus post, NASA technician Dave Fahringer worked closely with TriMech Manufacturing Inc.'s Applications Engineer, Chris Cole, to best utilize their FeatureCAM product with Okuma's THINC-OSP control. Because each project is completely different with new features, new programming strategies are always required. Machine alarm conditions would put a stop to the work if the code was not in order. "After considerable tweaking, we seem to have it nailed now," Fahringer says. "TriMech really stuck with me to get the post right, and I am very thankful for that."
Delcam's FeatureCAM allows a programmer to draw or import a part, identify the part components such as holes and surface milling, and in many cases, simply click the simulation to generate the necessary NC code. The program automatically selects tools, calculates feeds, speeds, stepovers, and depth of cut, determines roughing and finishing operations, and generates toolpaths and NC code flawlessly. The post processor library has many posts and the programmer/operator can adapt, rename and edit those to create custom posts.
The Okuma THINC-OSP control is a true PC-based, open architecture platform that uses standard G- and M-codes. With a 40GB hard drive, the control can accept practically any third-party Windows-based software. "The touch screen is much larger on the new control and being Windows-friendly helps the operator," Brady says. "He is able to make the edits or other quick-changes easily on the machine or by importing programs to the control through the Ethernet."
Another technological upgrade was the tool availability on the new multi-tasking machine. Whereas the old machines had a turret with twelve spaces, the operator could only use about six tools in order to avoid interference with the job or the chuck. "We use about 15 to 20 tools in it for the current job and we can now spread them out through 40 tool slots," Brady explains. "We use small drills, larger drill chucks, different turning and facing tools and the holder is set up to cover just about anything that may come in. That way we don't have remove the tool from the turret, clean it up and then re-insert another tool."
Using mostly aluminum, the NASA group is getting heavy into the steels - 13-8 stainless steel and Vascomax steel - a very hard, "nasty" steel, according to Brady. "It slows the process down - you can't rush the process, but it is durable for what we are doing," he explains.
"It's a different approach here [at NASA Langley Research Center] than out in the business world where you are trying to make money and utilize every inch of the machine to make the part from five minutes to two minutes," Brady says. "If we had 100 parts to do and they were all the same, then we'd make the time to look into streamlining the operation further. We don't put a lot of emphasis on that here, but we do try to be more efficient in order to meet our compressed schedules and get more jobs out in a timely manner. With new machines and new technology, we can do that."
With approximately 90% of the wind tunnel models being applied to future aerospace projects, Brady's team will have a good chance of seeing their hard work applied to the space exploration in approximately three to 10 years.(end)
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