Grob Systems Inc.
Complex aerospace machining at SixDigma, Mason, Ohio.

Universal Machine Controls Tight Tolerances for Custom Aerospace Shop

Dec. 23, 2021
SixDigma is executing complex manufacturing project with tolerances within 1/1000th of an inch thanks to a compact, large-work envelope machine.

SixDigma is a custom-manufacturing business in Mason, Ohio, that specializes in “advanced integration of CAD, CAM, and CNC systems to solve complex machining problems in aerospace applications.” The team includes experts in design, manufacturing, and process development, who have overcome some tough manufacturing challenges.

Part of meeting those challenges is having the best possible equipment in their shop. Recently, SixDigma added a GROB G350 universal machine to expand its machining capabilities, and thanks to the machine’s high precision and effective design, SixDigma has seen an improvement in machining tolerances and efficiency.

With its primary focus on aerospace customers – customers who manufacture products like aircraft engines – SixDigma’s processes are developed for materials like titanium and Inconel, when off-the-shelf manufacturing solutions will not suffice. Its customers seek manufacturing solutions that are more exact, more repeatable, and more efficient than other existing options.

One significant aspect of SixDigma’s business comes from adaptive machining solutions. Customers come with parts that have been forged, cast, 3D printed, or otherwise produced with methods that lead to slight variations between each part. SixDigma experts work to develop digital manufacturing solutions that include toolpaths adapted to the part variations.

The machining tool paths must be adapted to the parts’ existing geometry so that the resulting products are highly consistent, with usual required tolerances down to 1/10,000th of an inch.

Deciding on a universal machine

Given that SixDigma works with major aerospace engine manufacturers and suppliers, its experts are familiar with nearly every type of CNC machine. When it came time to upgrade the in-house equipment, they looked for a CNC machine that could support their adaptive machining work.

After trying out a number of different machines, SixDigma experts realized that a GROB machine was uniquely positioned to satisfy their accuracy and machine stability requirements.

“After evaluating many top-tier five-axis machines, the GROB universal machines proved to be best when it came to satisfying all of our requirements for part dimensional quality and machine stability,” said Edwin Gasparraj, founder and principal consultant at SixDigma. “After using machines manufactured by GROB in a variety of settings, our team went out to the GROB facility for some final testing, and we ultimately selected the GROB G350 universal machine for our shop. It has all of the premium machining capabilities we need, without a premium price tag.”

Improved efficiency

Gasparraj noted the GROB G350’s compact machine exterior compared with the large machinable volume – and the large part sizes made possible by the machine’s unique working envelope. More than that, the compact size compared with large machinable volume adds the stability that SixDigma needs for the demands of aerospace applications.

GROB’s kinematic arrangement puts fixed-frame components close to the machining envelope, such that even the most extended tool position is never more than a foot away from the fixed frame – which provides stability for both the part and the cutting tool.

“Our experience with our new GROB G350 proves that it’s one of the most stable machines we’ve ever come across,” Gasparraj added. “Given the increased force placed on the machine by the hard aircraft materials we use, the stability of the machining action is critically important.”

The G350’s high stability also translates into greater production efficiency for SixDigma. Because the GROB universal machine can deliver tolerances up to 10x more precise than even the highest precision required by SixDigma’s customers, repeat work is almost never necessary.

“In our adaptive machining solutions, we’re chasing tolerances that are some of the smallest in the industry at about +/-10/1000th of an inch,” Gasparraj said. “With the G350’s ability to maintain tolerances down to 1/1000th of an inch in most cases, accurately and repeatedly, we’re able to overdeliver on part quality to even the most demanding aircraft customers.”

Ease of maintenance, and more

“GROB is known for service and for valuing technology,” Gasparraj added. “The fact that everyone working at GROB can explain in detail what’s happening with the machine and how to service it effectively and holistically was a major selling point.”

Gasparraj specifically pointed to the ways in which GROB makes it possible for customers to easily perform necessary service on its own machines without needing a technician to come in person, thus improving uptime and efficiency.

“GROB uses some of the same components for hydraulics, pneumatics, cooling systems, and more, making it easy to stock a small number of spare parts for the machine,” Gasparraj said. “We can stock fewer than 10 major components and still maintain confidence that our machine can be up and running with minimal hassle.”

Gasparraj added that his team has been impressed with how the entire GROB universal machine is clearly laid out, with separate cabinets for hydraulics, pneumatics, and the cooling system. Paired with descriptive error messages that pinpoint issues to a specific system and clearly labeled components in each cabinet, this clear and precise layout adds to the machine’s overall efficient running and upkeep.

“Due to the rapid nature of our business, time saved is always more important to us than anything else, even the cost replacement components. When we’re working on a critical project, we need to be able to get up and running and staying that way,” Gasparraj explained. “The attention to detail in the layout of the machine ensures that we never spend more than a few moments identifying a problem, and we can always be confident that when we make a fix, it’s the right fix. The resulting improvement in uptime over other machines is incredibly valuable in the work we do.”

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