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Shop Rode Automotive, Transitions to Aerospace


Smiths Machine (Cottondale, AL) is a second-generation family-owned business that has transitioned from being a highly successful supplier of automotive parts (See Manufacturing Engineering, to becoming a go-to supplier for defense and aerospace manufacturing. The change in direction for the company was not without its challenges. “Defense and aerospace part manufacturing requires a different business approach altogether,” said Tim Smith, vice president. “It is specialized work that requires special approvals, log-down processes, and complicated procedures. The complexity is challenging. And it all starts with a different way of thinking, more of an engineering approach than a production approach,” said Smith.

The company needed to build a new business model and the operations to support it for the defense and aerospace machining market which is characterized by small lot counts, generally lower margins, and a very low tolerance for errors. Scrap rates thought to be nominal in the past would now be out of the question. “You can’t make a $6000 part and have a 30% scrap rate or even a 10% scrSmiths Machine has achieved consistency, quality, and precision required for machining complex parts for the aerospace and defense industry with DMG Mori machines with Siemens NX.ap rate,” said Smith. “The emphasis is not on throughput, but on the high-quality, highly precise manufacturing of very complex parts.”

Based on those three inseparable machining requirements—quality, precision, and complexity—Smiths Machine set out to reach its greater potential in the machine tool market, not as a production machine shop, but as a company focused on complex part manufacturing. Having achieved some early success in this new direction, the way forward for the company soon could be summed up more simply: “The more complex the part, the more competitive we are,” said Smith.

To protect and grow this competitive advantage, the company’s leadership knew that their internal processes and technology needed to match up with the unique requirements of the defense and aerospace industries. Major investments in large, complex five-axis machines would have to be enhanced by equally complex control capabilities. Smith said a decision made previously by the company came into play in the transition to defense and aerospace machining.

Traditionally a milling and turning company, Smiths Machine first teamed up with DMG Mori and Siemens in 2000 to establish their singular machine tool platform. This brought about a synergistic approach to complex milling and turning; an advantage that took on greater significance when the company decided to focus on the defense and aerospace markets later in the decade.

“Siemens controls were available on DMG Mori milling and turning machines and that was a natural fit for us,” said Smith. The DMG Mori/Siemens platform has enabled Smiths Machine to establish and maintain a high level of operational proficiency. The central advantage here has been the ability to invest, train and keep his people moving forward based on a stable technology platform.

“The technology and the people using it are the backbone of our organization,” said Smith. “Even with 25 machines, we can share knowledge between the milling and the turning machines. The common control is a Siemens Sinumerik 840D sl. Our technology purchases are based on where we want to be in 10 years, not on a workforce that is fractionally trained and a platform that can rapidly deteriorate due to a change in market or employment conditions.”

An example of this singular platform advantage is the control’s similarity across milling and turning operations. “All controls are customized to a certain extent,” said Smith. “But unlike Siemens, many other control series are individually customized so that the keyboard layout will be different from machine to machine. The Sinumerik 840D sl CNC is consistent. So when you train your operators, you can say, here’s the job button, here’s the axes button, here’s your alarm button and your offset button. And this level of consistency extends to a graphical interface that really complements how we teach and learn.”

Smiths employs a breadth of visual techniques to foster education, efficient information sharing, and quality control. “We are a very visual company,” Smith said. “We use a lot of colors and we buy a lot of printer toner. Our parts inventory uses color-coded tags and the same is true across our production. We use yellows and blues and reds for consistent instruction. And the Siemens 840D sl control uses the same approach. You are guided visually for such things as axis direction, approach point, final depth, and other variables inside a cycle. And this is true from control to control for milling and turning.”

According to Smith, visually guided information flow is characteristic of today’s complex range of next-generation electronic communications, because this speeds understanding and information sharing. Whether for a smart phone or a CNC, graphically guided interfaces enable rapid learning and proficiency, a fact that has been well leveraged by the Siemens 840D sl control interface design.

Gerhard Hetzler, engineering manager at Smiths Machine, has experienced first-hand how the company’s singular platform approach has brought continuity to such manufacturing functions as postprocessors, machine simulation, NC code, and control functionality.

While the Siemens 840D sl control has evolved in significant ways over the years, Hetzler said these changes have served only to accelerate the performance of the programmers and operators, rather than impede them with new and different procedures. The control platform has also given Smiths the freedom to create custom cycles that can be copied and shared from control to control and machine to machine.
Cycle 800 function within Siemens NX supports the programming of 2 ½ axis and 3D milling throughout the rotation of all X, Y, Z planes while maintaining a zero offset. All machining cycles can be used, and functions include automatic shifting of zero offset, tool length, and radius compensation in rotated planes and compensation of machining geometry.
“I’ll give you an example,” said Hetzler. “To catch occasional entry errors on the tool management side, we created a cycle that checks the length of the tool and within a specific tolerance. So within a matter of milliseconds, the control compares that value to what was entered in the tool management side. If the tolerance is exceeded by 2 mm, the control immediately stops the machine.”

Another advantage resulting out of the DMG Mori and Siemens relationship is the continued simplification of complex cutting operations, especially in the area of angular milling heads. “Siemens has come a very long way to improve the cycles and support related to milling heads,” Hetzler said. “Aerospace requires a lot more use of angular milling. Even a five-axis approach can’t do it. You need an angular milling head. I would put this on the top of my list of the advantages DMG Mori and Siemens have developed. And this relates to another important development, Siemens NX.”

Siemens NX software integrates CAD, CAE, and CAM for faster part manufacturing, encompassing all areas of tooling, machining, and quality inspection. NX has become integral to Smiths Machine’s CNC platform because it supports part planning through manufacturing, with prevention of errors and related costs.

“Our ability to develop all of our own postprocessors in house is supported by Siemens NX,” Hetzler said. “We set up our angular milling heads in NX, so we can post the G-code before we even send it out to the machine.”

An early introduction to the power of NX came when the company found that it needed to write code to produce an especially challenging aerospace landing gear. The code took six weeks to manually program. This was before the company learned that it could do the same task in nine days using NX.

“Siemens knows five-axis machining and NX is a Siemens product that leverages five-axis,” Hetzler said. “As an example, we can do three-plus-two axis work in NX. There is a cycle for that called Cycle 800. So when NX outputs the NC code, the machine then also understands it. Other control brands will have a cycle that can be made to work, but they are a lot more problematic. We are talking about managing the change of plane, a concept that has been around for a long time and was always problematic to do. Now Cycle 800 in NX does it all for you.”

Cycle 800 makes programming the change of plane easier, faster, and with higher accuracy than traditionally calculated methods. “We would normally round off after the third or fourth decimal,” said Hetzler. “Now the control calculates to nine decimals. When you start talking microns, especially in the aerospace industry, it makes a huge difference. And this difference has been fully implemented by DMG Mori. They have invested a lot of time and money to make sure from their side that Siemens NX and Cycle 800 work 100% of the time.”

For more information from Siemens Industry Inc., go to, or phone 847-640-1595. To view the video that accompanies this story, visit: 


This article was first published in the April 2016 edition of Manufacturing Engineering magazine. Read "Shop Rode Automotive, Transitions to Aerospace" as a PDF. 

Published Date : 4/1/2016

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