Better safe than saw awry
Contract manufacturer promotes safety and gains efficiency by relying on lift truck and new saw loader
When a machine operator cut a bundle of barstock open to load into a saw, the bands popped, moving the blocks that were put there to safely contain the bars. The bars fell on the operator's foot and trapped it. Not wanting to duplicate that nightmare, engineers at Kirsan Engineering, Kenosha, Wis., set about to create a method of loading barstock that relied on lift trucks, not cranes.
Safety is the most important, and most often the least appreciated, aspect of manufacturing. Simply put, you can't do the job without healthy people to do the job.
Kirsan Engineering, Kenosha, Wis., kept that in mind when it took a look at the loading process for its band saw. The barstock that was loaded into the band saw's automatic feeder could be 12 feet long, 9 inches in diameter, and weigh as much as 1,500 pounds. The barstock, which was cut into slugs for the company's machining centers, had to be loaded with a jib crane in a multistep process that involved securing the material from the nearby staging area; lifting the load up and toward the saw; balancing the barstock properly to avoid damage to property and injury to the operator; and lowering the material safely and securely onto the saw.
"The thing I never liked about cranes are the straps. When do you change those straps anyway? They always get tattered and nasty-looking,"said Jerry Ring, Kirsan's general manager.
"When we built very large fixtures, I would have my hands under [the load attached to the jib crane] many times tightening fasteners. That's always concerned me. It's just not safe."
Kirsan made a commitment to develop a better way and came up with the Kirsan bar loader that is fed with its Clark CGP30 Genesis™ lift truck, not a jib crane. The extra motivation for the material handling equipment came after a third-shift accident more than three years ago.
Necessity: The Mother of Invention
When metal barstock arrives at Kirsan, the bars are banded together. The number of bars in the bundle varies, but the bundled stock is not to exceed 4,000 pounds per customer request.
One evening a Kirsan machine operator cut open one of the bands off of a bundle of barstock to load the saw. The operator thought he had blocked the bars sufficiently with 4-foot by 4-foot wood blocks, but once the first band was cut, he found out otherwise. The other bands popped, and three bars—12 ft. 8 in. in diameter—pushed past the blocks, rolling onto the operator's foot. The operator yelled for help for several minutes in the remote area of the facility before receiving assistance. He broke bones in the top of his foot and missed several months of work recuperating.
In addition, the company added a second Amada HA250™ band saw with automatic feed in 2004. Now two people were dedicated to keeping the saws up and running for most of the shifts.
"That was when [the need for a change] really showed up, when we had two employees manning the saw,"Ring said. "It's not a real high-value-add process to involve that many people."
The new saw loader eliminates the jib crane from the materials handling equation and—come to find out—the need for a second operator. One operator now uses the lift truck to lower the bundle onto the bar rack, made of 0.25-in.-wall steel tubing. When the bands are cut, steel pins prevent the bars from rolling off the rack.
To move the barstock or tubing into position for sawing, an operator moves the carriage underneath the material, engages the hydraulics that lifts two steel saddles designed to cradle the material as it's lifted off the bar rack, rolls the carriage over saw rollers that will feed the equipment, and lowers the steel saddles. Once the sawing begins, the operator then can load the material into the second saw or stage the material to refeed the first saw upon job completion.
"Once the operators started using this, they loved it. It's safe, simple, and saves them time,"Ring said.
Kirsan management loves it, too, because the operators have redeployed elsewhere.
"The operator is now efficient,"Ring said. "Once he gets the bars loaded and saws running, he can go and help out with assembly or packaging and then come back to feed the next bar or bundle in."
Making Some Changes
Kirsan management thinks this saw loader makes sense for other contract manufacturers and hopes to draw the interest of some saw manufacturers. After spending more than three years working on the overall concept, the company thinks the design is ready for market. In fact, the company owner has applied for a patent on the saw loader design.
Some of the design changes that have occurred include:
- Adding hydraulics with limiting valves, which help the lifting arms and steel saddles lower at a more uniform rate. That helps to prevent dropped barstock that might result from a heavier end dropping faster than a lighter end.
- Steel tubing construction that is much stronger and aesthetically pleasing than the prototype's I-beam construction. The bar rack is capable of holding approximately 36,000 lbs. Meanwhile the hydraulics that run the lifting arms can handle barstock weighing as much as 6,000 lbs. and bars up to 20 ft. long.
The result is much better than any alternative that Kirsan ever considered, according to John Liegakos, Kirsan's engineering manager.
The company considered magnets and claws attached to the overhead jib crane. It even thought about a spreader device attached to the jib crane that was designed to make it easier to balance elongated material stock when lifted. But Ring and Liegakos worried about what would happen to the operators should one of those unsupported ends hit something heavy and force the other end to swing widely as a resulting action.
Now Kirsan doesn't have to worry about the jib cranes. It also doesn't have to worry about pouring a new 36-in.-deep footing—at a cost of $6,000 a job—each time it wants to move the sawing operation to accommodate a different factory layout.
"Let's face it. The guys doing this job are not always our most experienced guys,"Ring said. "There is more of a comfort level now as a manager that some of your lower-skilled guys are using something simpler and safer."
The FABRICATOR is North America's leading magazine for the metal forming and fabricating industry. The magazine delivers the news, technical articles, and case histories that enable fabricators to do their jobs more efficiently. The FABRICATOR has served the industry since 1971.