Fabriweld Senses Big Benefits with Load-Sensing Hydraulic System

“Our customers are telling us our presses are the best they have ever operated. They like the fact that the load-sensing hydraulic system makes the press more energy conscious, more consistent in operation, and quieter. And we all like the fact that our new hydraulic system is
15 percent lower in price than our previous system.”
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Tim Altomare, Fabriweld Controls Engineer
hydraulic press systems

Background

Sometimes a problem may not be evident until a better way is suggested. That’s exactly what happened when Eaton and a distributor Partner, Sentinel Fluid Controls of Toledo, Ohio, took a new approach to hydraulic circuitry on a press made by Fabriweld Corporation of Norwalk, Ohio. Fabriweld has relied on Eaton products and the hydraulics savvy of Sentinel for some 25 years in its fabrication of presses sold to Tier 1 and Tier 2 automotive suppliers and other industries. Among its leading production items is a massive press used to produce headliners in cars and trucks. The forming/trim press is a showcase of Eaton products, including vane and piston pumps and industrial
and proportional valves. The folks at Fabriweld had no complaints about the overall performance of the hydraulic system. Sure there were
issues with the press’ 10-volt command signal and acceleration and deceleration rates, but weren’t these just “normal” quirks?

Challenge

Not to Dan Lindstrom, Sentinel’s vice president of engineering; Rory White, sales engineer at Sentinel; and Fabriweld’s Tim Altomare,
controls engineer. “Together we took a cleanslate approach to the project by analyzing how we would design the system if we could start
from scratch,” Lindstrom says. “The press was equipped with a size 8 proportional valve for 100 gallons per minute of flow. On paper it was the right valve to use. However, depending on pressure drop, system flows varied all over the map, indicating the need for pressure compensation on the proportional valve. “I was also concerned about the valve’s resolution issues that caused the press’ 10-volt command signal to have limited functionality. In fact, any command above seven volts caused the press to operate at full speed, so the customer stuck to using only seven volts and under.” The press’ relatively tight ramp rates for acceleration and deceleration also troubled the
project team. “The pump was set at 2,500 psi—a relatively high pressure—to open and close the press at a rate of one inch per second,” Lindstrom says. “As the press closed and the load on the system started to go up, more and more of … Read more