Slashing Secondary Ops With New Swiss CNCs

One could argue that Bill Cox was born to run a machine shop. His father started Cox Manufacturing (San Antonio, Texas) around the same time he was born. When Mr. Cox was still a child, his father suffered a fatal heart attack. “At 12 years old, my mom asked me if I wanted to run the business some day,” Mr. Cox recalls. “There was never any question in my mind that that was what I wanted to do.” In 1980, he officially became president of the company . He was 24 and filled with goals to diversify the customer base, bring in new technology and become more efficient.

Cox made the logical progression of equipment acquisitions as dictated by production opportunities. Having started with Swiss cam machines and purchasing fixed headstock cam machines shortly thereafter, Mr. Cox moved into multis, then two- and three-axis CNC equipment in the ’80s, Swiss CNCs in the early ’90s, and most recently the CNC Swiss Decos.

The company employs 55 people. As labor costs have continued to grow, Mr. Cox has begun to realize that the only way to maintain profit margins is to become more efficient. Analyzing his operation, he honed in on eliminating, or it least drastically reducing, secondary operations.

“All of my initial objectives—diversifying, keeping up with technology and continuing to improve—go hand-in-hand; it’s sort of a ‘Catch 22’. A shop needs modern technology to attract new work, yet shops often need a customer commitment to drive the purchase of new capital equipment,” Mr. Cox says.

So 3 years ago, Mr. Cox decided to install two Tornos Deco 2000 CNC Swiss-type single spindle screw machines. “For over a year, we’d been doing time studies with Tornos engineers in Brookfield, Connecticut. We considered parts already in house and new quote opportunities. I even set up extensive spreadsheets analyzing costs and payback,” Mr. Cox says. “Then a customer came to us with a high volume job that could be made complete in one setup on a Deco. We bid competitively, won the job, and purchased two machines. Unfortunately, as it happens in the jobbing business, the customer’s order didn’t quite match up to the original projections.”

With two new machines practically idle on the shop floor, Mr. Cox and his team went after new work. He primarily placed ads in industrial directories because he did not have a sales force per se. The effort paid off in new customers in the medical, automotive, defense and oil industries. In the meantime, Mr. Cox kept the Decos busy with jobs already in house—jobs that were contentedly running on conventional multi-spindles and Swiss-type CNC machines. According to Mr. Cox, he learned the capabilities of the new technology quickly through tooling up and running these different types of jobs.

“The Deco was a fresh concept from Tornos and a breakthrough from a traditional screw machine shop’s perspective,” Mr. Cox says. “It actually comes close and often beats the cycle times of a cam machine, while providing the accuracy and flexibility of a CNC. The programming is a bit different than a conventional CNC; however it provides significant cycle time advantages.”

Mr. Cox found that the Deco, with its proprietary software method to eliminate non-productive time, could even outperform multi-spindles. Because of the Deco’s ability to completely machine complex parts in one setup and run unattended at high machine efficiencies, Mr. Cox was moving jobs from Davenports to the Deco. Also, compared to the conventional CNCs, the Deco provides cycle times at least 30 percent faster on most of Cox’s work. For instance, Mr. Cox referred to a complex stainless threaded part that previously ran on a fixed headstock CNC and took 3 minutes to produce. Now it takes 2 minutes on the Deco.

“I would say the key benefit is the elimination of secondary operations. They are the nemesis to productivity,” Mr. Cox says.

An example is a 5/16 hex brass center conductor clamp. The blanks were previously run on multis and then milled and drilled on a CNC milling machine. The typical run is 200,000 pieces.

“When we retooled this part to run on the Deco,” Mr. Cox says, “we were able to make the part complete in one setup, unmanned no less, at 16.7 seconds per part.”

In operation, first the front of the part is milled to produce four posts. The spindle is then programmed to halt stop on one of the flats and the part is cross drilled. The part is then cut from the stock and brought up with the subspindle for drilling and tapping the center of the part. While the subspindle is working above, a new piece is fed to the main spindle below, overlapping operations of the next part. With two parts being machined simultaneously, the Deco optimizes machine time, according to Mr. Cox.

Cox is ISO 9001:2000 certified. When a new project comes in, the quality manager develops an inspection procedure for that part. The manufacturing engineers review the procedure and identify the key features that need to be controlled during the process to ensure tolerances are maintained. At the beginning of every attended shift, the operator checks every feature on the inspection procedure checklist and then continues to sample parts at pre-defined intervals. The process is also audited periodically by a quality inspector.

“As a shop owner, I think our biggest challenge is to continue to use technology to reduce the direct labor in manufacturing and to be continuously more efficient. Incorporating Tornos technology, such as the Decos, is one of the best ways to get us there. It’s by far the most efficient equipment in our shop.”