Page 13 - MetalForming December 2017

Overall view of the entry conveyors.
Shown here is the exit (chain conveyor) for removing two sets of stacked parts simultaneously, and extension arms used to address tailout issues.
Blanks are stacked with great precision.
into an auto- mated cell for forming. And, as if multiple-piece sets with irregularly shaped parts isn’t challeng- ing enough, longer blanks exit the blanking press at angles to 45 deg. to maximize material usage, meaning that these parts must be repositioned in
order to stack properly.
Automation Is Key
After receiving a quote package from Magna in early 2015 to take on the work, Shiloh set out to find an automated solution. “We sent BMC (Bachuber Manufacturing, Inc.), a provider of press-automation equipment, an RFQ in Novem- ber 2016, and received and approved BMC’s quote in January
of 2017,” says Mike Cousineau, Shiloh’s continuous-improve- ment manager. “The automated line was implemented soon after. However, Shiloh began processing the parts in 2016, which meant several months of manual unloading and stacking.
“With each stroke making two parts, a left and right part, the parts come off the press one after another,” Cousineau explains. “Initially we lined up four people to pull the blanks off of the conveyor and stack them as the press ran, which, of course, created a lot of ergonomic and safety and issues. The need to automate was clear.”
Equally clear was Shiloh’s requirement to keep it simple. “We did not want a complex six-axis robot system,” says Jason Jones, Shiloh’s plant manager. “We wanted this to be a simple-to-operate two-axis system.”
The end result works like this: Blanks feed from the exit conveyor of the press onto the incoming split conveyor of the stacker, where they are stopped and oriented. The BMC 1401 stacker’s dual 48-in. gantries alternate between picking up both parts with electromagnets, and move them to the parts nests for stacking. The parts nests have adjustable guides to accommodate the different part geometries and enable uniform stacking.
Each parts stack is controlled by the operator, who enters the desired number of pieces per stack in the stacker’s human-machine interface. When the stack count is reached, an integral 15,000-lb. lift table lowers the stacks onto an exit conveyor. The stacks then convey out to a position where a forklift moves them to a shipping location. The press remains in continuous operation throughout.
To arrive at the final system setup took some customiza- tion, says Billingsley. “When the conveyor was originally built, it was a solid shaft that ran both belts at the same speed using one drive,” he says. “Before we put it into pro- duction, we saw that the parts exited at as much as a 45- deg. angle, so we split and modified the conveyor and added a second drive to change the speed in order to rotate the parts into proper position for stacking.”
“The angled exiting of parts is necessary because the exit end of the press measures 75 in. wide and the feed-line width is limited to 72 in.,” explains Cousineau. “Because some of these blanks are up to 97 in. long, the strip layout and dies had to be designed at an angle in order for the blanks to properly exit the press.”
Further, to address tailout issues without interrupting part flow, telescopic arms were added to carry the tail past the part stack before placing it on the floor, says Cousineau. “Our challenge,” he says, “was how to get that tail through the machine without hurting parts flow, and without moving the machine away from our press to ensure that alignment stays true.”
Team Effort
Cross-functional efforts figure prominently into the Shiloh Production System (SPS) continuous-improvement efforts,
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