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Volumetric Error Compensation Improves Large Machine Accuracy By Over Fifty Percent

The tightest tolerances of military and civilian air and spacecraft cannot be hit by many machine tools as installed, and the designs of these crafts are only getting more complex and demanding as time goes on. Even if machine tools are levelled and squared at installation, they often need more comprehensive Volumetric Error Compensation (VEC) to repeatably produce accurate parts. So, when Flying-S was looking to expand into larger components, they needed to ensure the full working volume of their new C.R. Onsrud gantry. API Services are partnered with all new C.R. Onsrud installations.

Using an API Radian Laser Tracker and SmartTrack Sensor (STS), API Services was able to:

– Evaluate and square the machine and scales at installation

– Perform VEC to reduce errors by more than 50% across the entire working envelope

– Unlock additional applications for Flying-S to perform with the machine

Flying-S started in a hangar barn home in 2001 in Crawford County, Illinois, USA with just a couple of machines and a CMM tucked in the corner. The quality of Flying-S’ people and production grew steadily over time, until they were able to move into a much larger facility in 2012 which now houses more than 90 employees. But as the military and civilian air and spacecraft industries continued to evolve, Flying-S found themselves needing to machine larger components to support their customers’ needs. Wanting to stay with the Fanuc controllers their operators were familiar with, the team at Flying-S determined that a G Series five axis moving gantry fixed table from C.R. Onsrud would have the working envelope they needed. And it was early in the quoting process with C.R. Onsrud that Flying-S learned of their partnership with API Services.

Across a machine that has 41ft (12.5m) of X travel, eight foot (2.5m) of Y and four foot (1.25m) of Z, Flying-S’ main concern was the accuracy and rigidity of the machine throughout its entire working volume. And because of C.R. Onsrud’s partnership with API Services, Flying-S has access to an expert team of Real Metrologists from the beginning of the process. API Services was present right from installation. As the machine was assembled, API Services’ Application Engineers were onsite, evaluating the machine’s level, squareness, and accuracy from the start. When the machine was assembled, it maintained an accuracy of .0015” across it’s entire 41ft (12.5m) machine length.

As Flying-S was looking to hit even tighter tolerances for aerospace wing manufacturing, they added Volumetric Error Compensation to their package from API Services. API Services’ VEC uses the API Radian Laser Tracker and STS to provide real-time 6DoF measurements for the entire working volume of a large machine tool. This allows the proprietary software to create a complete error map of the machine tool which can be loaded into the machine controller for compensation and improved repeatability.

VEC from API Services reduced the errors in Flying-S’ new machine tool by more that 50%, from .0015” to ~.0006” anywhere in the work envelope, any orientation of the spindle repeatably. That dramatic change in repeatable performance has unlocked applications for Flying-S that would have previously been unreachable.

“Our engineering group is able to say yes on the phone, whereas before they were like, well, we don’t have that travel,” says Peter Bowman, Manufacturing Engineer at Fling-S. “The accuracy that API has been able to provide us has given us the ability to produce eight-foot by eight-foot parts in a four-foot volumetric area on parts that are wings that are 41ft long. We’ve never been able to have that capability.”

And that increased capacity was the start of a years-long partnership between API Services and Flying-S that has changed the way Flying-S is able to do business.

“We will always purchase API Services when we buy C.R. Onsrud, from now on,” Peter says. “It has affected every aspect of Flying-S. It literally changes the way your machine works. It is so much more accurate.

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