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Users Opt for Hydraulic Machinery Retrofits
New controls bring added life to older systems
By Design News Staff -- Design News, February 17, 2003
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Falling off a log: By retrofitting a "veneer lathe" with a new motion control system, users eleiminated the need for a brand new machine. |
Newton, MA — Newton, MA—With the economy still struggling, industrial suppliers are watching a new trend emerge in the fluid power sector: Instead of replacing aging hydraulic presses and machine tools, end users are now opting to retrofit their existing hydraulic machines with new controls.
"It's not surprising," notes Curt Wilson, vice president of engineering for Delta Tau Data Systems, Inc. (Chatsworth, CA, www.deltatau.com), a maker of motion control cards. "Companies ideally want new machines, but the controls go obsolete long before the mechanics, so in a recession they opt to replace only the controls."
Makers of the motion control systems, such as Delta Tau, Galil Motion Control (Rocklin, CA, www.galilmc.com), and Delta Computer Systems (Vancouver, WA, www.deltacompsys.com), say they are seeing a sharp jump in the number of hydraulic-based machines that are being retrofitted. The reason, they say, is twofold: Closed loop hydraulic systems require high-frequency processors; and high-frequency processors have dropped enough in price so as to make new controls more attractive. "Sensing the position of a cylinder can be hard," Delta Tau's Wilson says. "You need good sensors and fast processors to do it."
As an example, Delta Computer Systems recently completed a retrofit with Altec Integrated Solutions, Ltd. (Vancouver, BC, Canada) on a "veneer lathe," which uses 32 hydraulic axes to cut blocks of wood into sheets of plywood. Delta's RMC Motion Controller controls the hydraulic cylinders that lift, turn, and line up the wood blocks, as well as those that position the cutting blades, with resolutions of 0.001 inch in most cases. The company's engineers say that the RMC module is a good choice for such tasks because it allows for incorporation of up to four motion control cards, each of which employ field programmable gate arrays (FPGAs) to gather data from transducers around the machine. Using the RMC modules to control the hydraulic cylinders, engineers say that the existing machine can peel a log as efficiently as a new lathe.
Press on
Delta Computer also retrofit an existing bushing press with a new motion controller. That module, capable of controlling position and pressure, replaces an existing system that only controlled position. CEO Steve Nylund says that because the new machine also controls pressure, it's better able to recognize whether a bushing is being properly placed in its housing. Some bushings, he says, fit too snugly; others fit too loosely. The machine "knows" if a bushing is too loose or too snug. The end user now enjoys higher manufacturing yields because fewer housings are damaged during the placement process, Nylund adds.
Similarly, engineers at Delta Tau Data Systems say they are seeing a rise in such press retrofits. These presses, they say, are better than existing ones because new controllers, such as the company's PMAC2, oversee both position and force. That's particularly valuable in sheet metal presses, they note, because it allows for the presses to use position control for initial placement of the press, then switch to force control as the sheet metal bending process takes place.
Makers of motion control systems emphasize that such retrofitting efforts can be a fraction of the cost of a new machine. In many cases new machines may cost as much as $1 million, whereas a retrofit can be less than $100,000, they note. Delta Computer's Nylund says, "If they do a retrofit, the return on investment is very good."
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