Page 23 - MetalForming March 2012

rapid expansion of its new welding facility. Ten robotic-welding cells, for assembling engine mounts and cross- member torsion bars, landed almost immediately on the plant floor, and another pair of robotic-welding cells had moved in by 2001.
“We grew rapidly and significantly,” says Friedman, “but then culture shock hit us in 2004 with the launch of the GMT900 truck platform. That program included a new type of suspension sys- tem that reduced our sales volume for the platform by 65 percent, as most of the parts we were manufacturing were designed out of the vehicles.
“To fill the void, in 2004 we were awarded about $12 million in trailer- hitch business from GM,” continues Friedman, “and by May 2005 we were GM’s sole supplier of trailer hitches for pickups and SUVs.”
Trailer-hitch work from GM, as well as takeover work from other hitch manufacturers, led to the installation of another five robotic-welding cells at the facility, including a quad cell with four robots (from Motoman) added in 2009. The quad cell originally was com- missioned for welding Hummer axle crossmembers, and now is being repurposed for the next generation of
Northern Stamping can track every detail of every weld cell through each cell’s human- machine interface (shown here at far left), including production and downtime and the causes for any hiccups.
GM’s heavy-duty hitches. Also in 2009, the company added its first robotic resistance-welding cell. In total, the welding plant now is home to 70 robots as well as 60 hourly workers—includ- ing three welding engineers and three welding technicians—working across two shifts.
Plugging Away at Productivity and Quality
Slowly but surely, and with impres- sive, consistent year-over-year results,
the company has plugged away at decreasing weld-cycle times, increas- ing quality and optimizing weld-cell uptime. All the while, it’s shifted responsibility for quality to the opera- tors, while providing the required training to allow this shift in responsi- bility to occur. The firm can track every detail of every weld cell, says Sheffield, through each cell’s human-machine interface (HMI), including production and downtime, and the causes for any hiccups.
“The operators’ jobs are to keep the robots moving and the cells in pro- duction,” he says. “And data collection over the company network ties every- thing together. Managers can see live, in real time, exactly what’s happening at every cell in the plant, and who’s responsible at any given time for meet- ing production goals at each cell. In addition, every assembly we produce here has an individual lot-traceability stamp on it—that’s their signature.”
Personal responsibility on the shop floor has positively impacted several measurables at the company. Most notably, weld-cell downtime through- out the facility has dropped from 28.6 percent in 2004 to 16.2 percent in 2011. Downtime is segmented, tracked and recorded by several unique causes:
• Component—out-of-tolerance parts coming to the welding cells;
• Contract—mutually agreed-to
An Impressive Downtime-Reduction Track Record
—a measure of overall robotic-welding cell downtime as a percentage, from 2004 through 2011
Downtime issue
2004
2006
2010-2011
Component
7%
5%
1%
Contract
7.5
7.5
8.33
Management
2
2
1
Maintenance
6
5
5
Operator
1.5
0.25
0.10
Wait
3
2.75
2.57
Overall actual downtime
28.6
24
16.2
Overall goal
27
22.5
18
Northern Stamping segments, tracks and records robotic-welding cell downtime by sev- eral unique causes: component (poor-quality parts coming to the welding cells), con- tract (mutually agreed-to downtime, according to the union labor contract, for personal issues), management-related (for training, scheduled meetings, etc.) maintenance- related, operator-related and wait.
www.metalformingmagazine.com
MetalForming/March 2012 21