Beckwood Press Co.
889 Horan Drive
Fenton, MO 63026-2405
(St. Louis)
Phone : 636.343.4100
Fax : 636.343.4424
info@beckwoodpress.com
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Technology Center
Beckwood's Accu-Flex Mixes Electric, Hydraulic Technologies
Beckwood Press Co. has engineered an inexpensive way to use the best of both servo and hydraulic technologies in a maintenance-friendly format. The Accu-Flex (patent pending) is a line of servo-driven hybrid presses, designed to provide users with unlimited flexibility with precision performance for both position and force control. (Click here for examples)
Jeffrey E. Debus, Beckwood's Vice President, says that the idea was to take advantage of widespread servo-motion technology (particularly vector drives), of VFDs-and combine it with hydraulic actuators in a package that can be far less costly in many true servo-hydraulic press applications. "Servo-hydraulics are the right fit for many challenging applications, but can be very expensive in certain cases", Debus says. "Their maintenance costs, their up-front costs and their complexity can be very high and have been excluded from many jobs that could use its benefits."
Beckwood manufactures many presses with servo-hydraulic capability, but noticed certain applications in the 5-
150+ tonnage range were too costly for the application. In response to that cost-versus-need problem, Beckwood wanted to answer the question: How can we do this more effectively and more efficiently for our customers?
The answer is the Accu-Flex press. Accu-Flex users can choose between position control with force override or the inverse, depending on whether precision force or position is more important for that application at hand. The system uses an Allen-Bradley VersaView interface and is completely programmable: Force, approach speed, return speed, distance and dwell time all can be changed instantly. "There's no parameter in the cycle that you cannot program", Debus says.
In addition, the control system provides real-time trending that allows users to plot process variables, such as position or pressure, and observe how they interact. An operator can store those scenarios and download them via Ethernet either to a computer database or a printer. For industries with strict certification requirements, such as aerospace or assembly, those capabilities provide the kind of traceability a shop needs.
The system also has built-in go/no-go gauges that can be programmed to accept or reject parts based on certain user parameters that are needed to produce a part correctly. For instance, Debus says, if you know you need 6 tons of pressure to insert a rod into a bushing 3 in., the system will reject parts if the machine happened to use, say, 5 tons or 7 tons. "It's all programming", Debus says. "If it deviates from what you told it to do, it'll tell you."
"It's really easy to tweak and change; you can change it on the fly", he says. "When you change parameters, the parameter curve will actually change dynamically to match what you programmed."
Beckwood offers the Accu-Flex in tonnages ranging from 5 to 150+ tons. That ‘sweet spot', marks the range where a ball-screw machine can't keep up with the tonnage and a true servo-hydraulic or servo press can't compete with the prices, "Provided that you are in that traditional hydraulic press speed application", Debus says. "We're a custom press builder with an experienced engineering team, so we'll analyze each application and recommend the right solution for each job. If you get to a certain point where your power-drive costs put you into a place where the servo-hydraulic price starts to match, we'll find the most efficient way of engineering your process and recommend that to you."
The blend of technologies might be easy to use, but getting the right mix engineered properly wasn't exactly automatic in the beginning. Beckwood essentially had to bring two disciplines together that don't necessarily intersect in the real world. "When we would say force control, the hydraulics guy completely understood; the servo guy had no idea what we were talking about", Debus recalls with a laugh. "Because in servo-motion, you're dealing with velocity and torque. In hydraulics, you're dealing with pressure and flow. So we had to work to integrate and blend those two technologies together so that they understood what each one correlated to."
"At the end of the day, they were all looking at each other saying, ‘We get it! We understand. This is great.' All the lights were coming on."
The result is a press that is highly applicable for R&D, production and assembly, providing another solution to the many application needs in the industry.