The Fabricator - November 2013

By Tim Heston, Senior Editor

In one area of Metcam’s shop floor sits a punch press that feeds parts to a robotic press brake, which feeds parts to an area with a hardware insertion press, and manual and robotic gas metal arc welding machines. Workers produce enclosures for a unit that converts the direct current of solar arrays into alternating current. Metcam won that large contract earlier this year, and part of what helped the Alpharetta, Ga.-based fabricator was that cell concept, built to produce the product family (see Figures 1 and 2).

Last year this corner of the shop looked com-
pletely di;erent. Back then workers assembled
components for a large electrical components
company. Metcam still does that work, just in a
di;erent place. Earlier this year that work had to
be moved to another building o;-site. But over
the months the company reduced work-in-process
(WIP) in another area of the plant, allowing it to
move the operation back into the building, trans-
forming inventory space into productive space.
Meanwhile, the company had another bottle-
neck to overcome—the powder coat line. So the
shop installed another paint line, but with an un-
usual parts washing system, a modular one that can
be assembled and disassembled over a few days.

All this change occurred not over years, but months. Adapting cellular manufacturing to the job shop can work wonders when it comes to productivity, scheduling, and on-time delivery. It also requires change—lots of it. But according to managers at Metcam, change is not a bad thing. It’s what continuous improvement is all about.

A Lot of Racking Going On

In February of last year ;e FABRICATOR covered
how the shop rearranged its shop floor into cells,
each with machines for cutting, bending and form-
ing, hardware insertion, and other processes. ;e
argument against manufacturing cells in contract
metal fabrication has always hinged on product
mix. Historically, manufacturers developed cells
that were product-specific. How could cells possi-
bly work for an operation with dozens, hundreds,
even thousands of di;erent part numbers?
Metcam’s managers had a di;erent perspec-
tive. ;ey discovered that for their diverse part
mix, every part was cut, most parts were bent, and
most also required hardware. ;ey also found that
separating these processes by department actually
created tremendous amounts of WIP. ;e cutting
department cut blanks and put them on racks. ;e
bending department retrieved those blanks from
the racks, bent them, and then put them back
on yet another rack. Workers processed the part,
racked it, processed it, and racked it.
So the company set up cells (initially seven, now
eight) designed primarily around—but not exclu-
sively for—product families (see Figure 3). Most
jobs flowing through a particular cell may be part
of the same product family, but not all jobs. Certain
hot jobs or short runs may be assigned to the same
cell, scheduled in between the longer runs.

According to Jerry Ward, vice president of operations, the arrangement promotes high-velocity production. Parts may be cut, deburred, bent, and have hardware inserted in the morning; welded in the afternoon and painted at night; then shipped to the customer the next day.

Ward added that flexibility, including the ability to squeeze in unexpected work, is one of the primary benefits of cellular manufacturing. In the past, if a hot job came in the door, the scheduler had to squeeze in the job between batches at every process: laser cutting or punching, bending, hardware insertion, joining, and assembly. All that squeezing Figure 1

In this new manufacturing cell at Metcam, parts flow from the punch press, to deburring, to a robotic press brake (in the foreground), and then on to manual and robotic welding (in the background).

Figure 2

A robot welds an assembly in Metcam’s newest cell. A robotic press brake is in the background, and to the left (out of shot) is a new turret punch press.