Prince Mfg. Corp., North Sioux City, S.D., makes a variety of components essential to hydraulic systems: pumps, valves, and cylinders—especially cylinders. Prince’s welded hydraulic cylinders are manufactured in four locations, and its Lewis & Clark facility, Yankton, S.D., is a 40,000 ft2 plant that typically produces as many as 400 cylinders per day in small-batch runs.
As you would expect, Prince are always looking for ways to increase productivity without sacrificing quality. Plant officials at Lewis & Clark identified an opportunity to improve production of a manual skiving-roller burnishing process that required frequent setups and multiple part programs. Discussions with Sunnen Products, St. Louis—well-known for its honing equipment—led to the development of a new automatic skiving and roller burnishing system, the SHD.
“Flexibility is key to our success,” says Colin Kathol, general manager of Prince’s Lewis & Clark plant. “Custom cylinders are designed to perform a specific function, and we need to be ready to produce when called upon.” Kathol explains that teams identified setups and part programs as areas where production time could be slashed, creating “a huge impact on our business.”
Prince Manufacturing installed an automatic skiving and roller burnishing system in a welded-cylinder production line to slash machine setup times 33% to 90%, depending on the procedure.
The Numbers Don’t Lie
The SHD is putting up impressive numbers at Lewis & Clark, as setup times alone are a fraction of what they were. “We’ve got frequent changeovers on four major types of set-ups on a daily basis,” reveals Kathol. “We may run 20 parts, do a changeover, run 20 parts, then do another changeover. So the faster we can get out of one job and into another, the more productive we are. When we compared manual to automatic processing, the time savings per setup was as much as 20 minutes. Considering the number of part sizes we produce and different setups they require, it was like creating extra hours in the day. This translates directly to more parts per shift and, ultimately, higher profitability.”
The shop’s four typical setups have gone from 10 min to less than one; from 10 min to five; from 18 min to 12; and from 40 min to 20. In addition, fewer operator hours were required due to the machine’s easy-to-use control that stores part programs and runs them at the push of a button.
Most cylinders at the Lewis & Clark facility are 6- to 60-in. long, with 2- to 4-in. diameters, and surface finish specifications of 4- to 10-µin. RMS. “We actually have to be careful not to drop below 4 RMS, because the machine is certainly capable,” explains Kathol. “We’re getting a better finish and we are able to pick up the feed rate because this is very stout machine–built for heavy-duty operation and no vibration at all.
“The control’s ability to save, store, and recall part programs is also a major time-saver. We put a barcode that carries the part program information on each cylinder tube,” adds Kathol. “We scan the bar code, and the machine automatically sets up to that part program. Just push a button, and we’re making parts.
“A new operator can learn to run the SHD in a week or less because the control panel and all the sensors and safety features make it easy to learn and run. That puts more operators per shift on the floor who are trained to run this machine and lets us assign operators around in our shop to satisfy our workload. This is a big plus when it comes to scheduling our shop floor.”
The SHD’s integrated safety system features a light curtain, interlocks, hard guarding, and cages on the back of the machine. Machine overloads are avoided because sensors trigger an alarm if the oil level or spindle load exceeds a threshold.
A Combined Effort
Sunnen and Prince worked together in developing the new SHD skiving and roller burnishing system. “We learned a lot from the team at Prince regarding the features that maximize productivity and ease the stress on operators,” says Phil Hanna, product manager at Sunnen. “Their ‘shop floor view’ input was very important to the setup and safety features we built into the SHD, but we also received a lot of data from their engineers during the testing that allowed us to determine the proper spindle loads and other details of part programs and the machine’s operation. Coupled with our experience in honing, we’ve got the background and knowledge to offer the most cost-effective bore finishing solution based on the application.”
The companies plan to continue their collaboration to further refine specific part programs, develop improved tooling, and collect production data to ensure smooth, consistent operation. Kathol concludes, “Sunnen provides a complete solution with machine, tooling, cutters/rollers, coolant system, and training. Floor managers now can plan work flow, develop schedules, and even handle on-demand work, all because we automated our skiving/roller burnishing operations.”
For more information on Sunnen Products Co., call (513) 831-0010, or click here. For more information on cylinders, pumps, valves, and accessories form Prince Hydraulics, call (605) 235-1220 or click here.