Rotary bushings guide and support line-boring bar tools and help to facilitate accurate cutting while controlling heat, wear and chatter during such operations as boring the aligned holes for camshafts and crankshafts on automotive engine blocks. However, when rotary bushings go bad, the result can be costly as parts are scrapped and machines go down. A situation that Galaxy Industries Inc. of Canton, Mich., and Ford Motor Company's engine plant in Romeo, Mich., know all too well.
Galaxy Industries, performs machining work for major equipment manufacturers. It ran into trouble when the three rotary bushings it used to pilot line boring bars wore out near the end of an engine-block job it was doing. The shop had a spare set of bushings and thought it was out of the woods, but the problem turned from bad to worse.
"When the bushings wore out, we were at the point in the job where we were ready to bore seven crank journals in the engine block simultaneously," says Dale Funk, plant manager at Galaxy Industries. "What we didn't realize was that our spare set of bushings was too small, and we had already completely torn down the existing setup to install them."
The boring operation came to a halt for 24 hours, costing the company $150,000, and it had no way to recover that amount. What made the situation worse was that the spare set of bushings cost $25,000, another cost run-up that added to the money the shop already lost in time and on labor spent disassembling the operation. To cut its losses and to get the operation up and running again, Galaxy found and used a rotary-bushing retrofit package from Gatco Inc. (www.gatcobushing.com).
The Gatco package is designed as a quick-change, precision cartridge with a self-contained bearing assembly. It can be installed into a machine in minutes and eliminates much of the time-consuming and expensive replacement of individual detail parts that comprise the bearing supports that are built into machine housings. Rather than removing worn parts, ordering new ones and installing them, shops slip a Gatco cartridge into place and lock it down. Cartridges are pre-adjusted at the factory to customer specifications.
Galaxy Industries was back in operation within 24 hours of installing the Gatco bushings. Funk said his operation could have been down for as long as six weeks if it chose a different solution to the problem.
Ford Motor Co.'s Romeo, Mich., engine plant experienced similar downtime because of rotary-bearing problems. The shop needed to remove more material from engine blocks for a new, beefed-up engine for Ford's Mustang Cobra. Unfortunately, boring the engine blocks shortened bearing lifespans to three months.
"The job was very rough on our equipment," says Jim Malczewski, a manufacturing engineer at the plant. "Old bearings would fail prematurely, destroying tools and creating scrap. We also spent a lot of money replacing the broken tooling. So, when we redesigned our tooling, we incorporated Gatco retrofit bushings," he says.
According to Malczewski, the retrofit has saved the plant roughly $100,000. Some repairs were costing $5,000 each, and the plant was making repairs on a regular basis.