Page 29 - MetalForming June 2009

that moved forward to another piece of equipment that then loaded the part onto the next press. In the late ’80s and early ’90s, these setups got the call over robots owing to higher cycle times. But diesetting was a challenge.
“To dieset these lines, we would have to unplug everything, pick up the shut- tles with cranes and move them out of the way, then put everything back after exchanging dies,” Dively says. “Doing all of this at least once per day (tandem lines at Ford Woodhaven typically undergo one or two job changes daily), over the course of 20 years we had pins wearing out, cables getting crushed... very uncompetitive diesets.”
Robots Help Double Line Productivity
Ford replaced the straight-path automation on Line 8 with Fanuc R-2000iB/100P six-axis robots located between presses, along with Fanuc and R-J3iC controllers. The difference?
“Now we produce up to 550 to 575 parts/hr.,” says Dively, “and do so reliably. Quality is improved because the robots better locate parts on the dies.”
Also, diesetting has improved on a similar scale.
“One switch locks all of the robots, and we go in and replace the robot tool- ing arms, then command the robots to ‘go to dieset,’ where they position them- selves out of the way for die change, then we hit startup for the next job,” Dively explains. “That is much quicker and easier than with the old straight- path automation.”
On Line 8’s entry end, a robot loads the press with mild-steel blanks, 0.031 to 0.040 in. thick, from a manually stacked tray. After forming, the stamped doors, dash panels and reinforcement bars, primarily for F-150s and Explor- ers, are gathered, aided by an air-clutch- driven exit conveyor and automation that enables limited stacking prior to manual handling and rack storage.
“We may be able to stack four parts and then index for a couple of seconds, so the worker at the end of the line is not overwhelmed with parts rolling at him,” says Dively. “He receives a stack of
parts and racks them, and by the time he turns around he has another stack of parts waiting.”
Line 8 is dedicated to six or seven jobs, but took on three more jobs after a similar line went down a few months back. That speaks to the flexibility and speed built into the line, especially in the automation.
“We were running the original jobs on Line 8 six days per week to cover a
five-day production schedule, and now we are running those plus the three new jobs on a four-day schedule, and are lucky if we have stock to run on Fridays,” says Dively. “That’s what speed can provide. And we don’t store inventory, so the line has to be up and running.”
With assembly plants sending in orders, and blanks arriving from an outside sup- plier to meet orders for a particular week, if the line doesn’t run, assembly isn’t
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