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part,” he explains. “The press and robot basically handshake on a discreet level. In the case of a hydraulic press and robot, they communicate on a much higher level to actively handshake and know exactly what the other is doing. It is very complementary.
“For example, a hydraulic press can do anything anywhere in the stroke at any time,” Bisbee continues. “So the operation can be programmed to enable the robot to maintain control at a certain point in the stroke, and the press to assume control of the robot in another point in the stroke. Flexi- bility inherent in hydraulic presses enables this level of communication.”
Tandem Technologies in Action
The recent installation referenced above speaks to the efficacy of a hydraulic-press/robot solution. The new $2.2-million cell features a hori- zontal-acting 750-ton Greenerd deep- draw hydraulic press assisted by two Fanuc multi-axis robots. Prior to the installation, several vertical presses performed five draws on 80-100-lb., 0.5-in.-thick aluminum blanks.
“These 72-in.-dia. blanks had to be maneuvered by two or three employees into and out of the press,” recalls Bis- bee. “Being vertical presses, using cranes to place blanks and orient parts proved difficult.”
Given the large and heavy blanks, Greenerd proposed automating the front end with a robot loading the hor- izontally oriented press.
“We provided a cell where, on one side of the press a load robot places a blank in the press, and because the press is horizontal, holds the blank as the ram closes the tooling around the material,” he explains. “Once the press has hold of the blank, the robot exits and after the robot is clear, the press performs a draw. After the draw, a sec- ond robot on the other side of the press enters to remove the drawn part, clear- ing the tool and allowing the first robot to reload another blank for another draw. Here, a cushion assembly used during drawing ejects the part material from the tool.”
Prior to installing the new cell, explains Bisbee, the cushion would push the material part-way off of the tooling, then an operator would come in to manipulate the material, followed by another push and more manipula- tion—a time-consuming process that also required excessive manual reach and handling.
“Now, after the draw, an unload robot holds the drawn part while the cushion ejects it,” he says.
At this point, the robot essentially performs the same duties as employees had in the previous setup, but instead can maneuver material while the press ram opens and the cushion pushes, saving a large amount of time. This is where the robot and press communi- cate back and forth, with each taking direction from the other throughout.
This process repeats for five draws, with dome-shaped parts created from the master blank. Whereas the metal- former had taken roughly a week to run 25 blanks through this process, now, with the new cell setup, that’s been cut to a day-and-a-half, a 233- percent increase in productivity.
With the increase in productivity, the metalformer freed its vertical press- es for more work while improving employee safety, according to Bisbee. One operator still assists with loading pallets of blanks and another with removing drawn-part pallets, and pro- ductivity gains have delivered new work, so no employees have been replaced via this automation.
Consider the Automation Option
Chances are that a robot-press team can pay dividends for metalformers large and small. Dealing with hazardous materials? Experiencing bottlenecks due to manual handling? Manipulating large, heavy and unwieldy blanks or parts? Want to hold a forming operation to perform secondary processes in the press? All of these can be addressed with robotic automation. With costs decreasing and the learning/program- ming curve flattening, now may be the time to see where a robot teamed with a hydraulic press makes sense. MF

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