From amusement park rollercoasters to cranes, mining equipment, conveyors, automotive assembly lines, and many other applications, SEW-Eurodrive manufactures the gearmotors, electronics, and software that keep things moving. Based in Bruchsal, Germany, the company maintains a network of 16 production plants and 79 Drive Technology Centers in 50 countries around the world. The plant in Lyman, South Carolina, one of the four facilities in the U.S., is staffed by the 300 employees and incorporates more than 100 robots in its automated production processes. 

One of the principal products produced at the Lyman plant is the K series helical-bevel gear motor line, designed to deliver maximum efficiency and with low maintenance requirements with optimum ratio and torque. 

Main/Sub Spindle TOPlus mini chucks showing (left side pinion shaft, right side pinion head).

Larry Neely, toolroom supervisor at SEW-Eurodrive, comments, “Because our K box line is extremely popular and is used in many diverse industries, everything we have made for the last couple of years has been for customer orders. We don’t retain any inventory. In fact, demand is so high that, in the near term, we’re looking to double our production and, at present, we’re delivering more than 600,000 gear sets and housings per year,” said Larry Neely, toolroom supervisor at SEW-Eurodrive.

Quality control is critical to the manufacturing process, and tolerances are measured in microns. Robots are used to ensure maximum efficiency and accuracy. 

“Among the most challenging applications is the turning of the high-ratio pinion. Machined from 8620 steel, the process involves two separate chucks—one for holding bar stock, where we turn the bearing journals, and the other for finishing the head. Parts are run on two Okuma twin-spindle turning centers. Because we are turning the bearing journals and the head on two different chucks, given our tolerances the machining process is exacting and complex,” said Neely. “When we initially evaluated the Hainbuch system of precision workholding, we reviewed our entire production strategy and realized extensive benefits in both time and money.”

Originally, parts were produced from individual 2-inch diameter blanks that were held between centers. This required the cutting and facing of each part. Because parts were held by the pinion faces, using face drivers, they would have inconsistencies on runout and need to be processed after heat treat, after which a press was used to correct runout. 

Automated cell w/robot unloading finished pinions.

“Subsequently, we went with a quick-change collet system. Because the clamping force was not sufficient, we had to use a Carbonite coating to ensure rigidity while turning. The addition of foreign material also adversely impacted our tolerances. We had to chamfer the bars when bar feeding, and this, of course, increased our cost,” explained Neely. 

Edward Reames, southeast regional sales manager at Hainbuch America Corp., explained, “When we first saw the setup being used at SEW-Eurodrive, we knew that we could help. We recommended the Hainbuch TOPlus chuck and clamping heads. The superior clamping capability eliminated the need for Carbonite, and the unique hexagonal design allows quick-change capability with maximum repeatability. The geometry provides superior resistance to contamination and absorbs vibration. Larry agreed to a trial run, and we shortly discovered benefits that extended well beyond conventional workholding.”

“Thanks to the Hainbuch TOPlus system,” stated Neely, “we were able to eliminate the need for individual blanks and replace them with bar stock. This eliminated cutting, facing, and chamfering, as well as the need for Carbonite. We also eliminated runout and could change the tolerance from a 20-micron tolerance to 10 microns. The Carbonite we previously used resulted in excessive wear on our collets, requiring frequent replacement, and we no longer have that experience. We’ve also been able to increase speed and feed and extend tool life. 

The finished pinion blank.

“Because we turn the bearing journals on the bar stock side, we use serrated collets on the main spindle/bar feed side and smooth collets on the sub spindle side for the finished surface to prevent the part from getting marked up. All of the collets are from Hainbuch’s standard product line, so we don’t have to incur the cost of special tooling. All in all, the incorporation of the Hainbuch system and the many advantages we derived is one of the most dramatic improvements I’ve been able to make—and the most painless and least disruptive.”

“By taking the ‘long view,’ Larry was able to visualize changes that would impact not just workholding but the entire production process. Two of the machines at SEW-Eurodrive are now equipped with the Hainbuch TOPlus system, and another is on order,” Reames added.

Thanks to the improvements realized in part turning, Neely and his team are considering incorporating Hainbuch workholding equipment in generating high-precision gears, while eliminating expensive fixturing.

“We manufacture a series of high-performance gearmotors. The more accurate the gears, the more efficiently the motor can perform from an energy standpoint. That is critical as a means of cost savings,” Neely said. “We plan to incorporate the Hainbuch system in the process because Hainbuch products have quality that meets our own exacting standards, and quality is always worth more. The numbers prove it.”

seweurodrive.com

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