provided by: 
Jeremi Dobbs, plant manager at Muncie, Ind.-based Midwest Metal Products/Sheet Metal Fabrication Division (www.midwestmetal.com), has job routings down to a science. The job shop has invested heavily into automation with two flexible-manufacturing systems. One has a 1,500-watt laser and pallet tower capable of handling 15 to 20 tons of material, and another 4,000-watt system with a tower capable of handling 30 tons. Both loading and unloading are completely automated.
As sources explain, Dobbs has taken an often-missed step when integrating today's extremely fast cutting technology. From the get-go, managers knew the fastest laser-cutting systems wouldn't be worth their salt if bottlenecks ensued before and after the cell. Without planning, the hundreds of thousands spent for a high-end laser could actually increase wait times.
This, say sources, represents a wasted investment and requires shops approach today's blazingly fast lasers from a macro-perspective, analyzing how these systems can help increase, not detract from, the value-added work on the floor.
THE EQUIPMENT-DEPRECIATION ADVANTAGE
About six years ago, when Dobbs was transferred from the skilled trades department to the sheet-metal-fab shop, company managers sent him to Japan and elsewhere to learn the thought process behind lean manufacturing. "I was very fortunate," he says. "Our management team truly believed in the lean way of thinking. It's not just a set of tools. It really entails a true psychological shift in an organization."
The Japanese automation he saw embraced one financial fact: equipment depreciates, becoming cheaper the longer they are in service; highly skilled people, on the other hand do just the opposite (and rightly so). For this reason, any manual labor should add extremely high value, be it design-for-manufacturability work, critical process monitoring or quality checks. Every action a person makes—physical, cerebral or both—should accomplish a lot.
LEAN IMPLICATIONS BEHIND THE HIGH-SPEED LASER
"There's been a lot of focus on high-speed plasma cutting with the laser (see sidebar, page 38)," says Lou Derango, 2D product manager for Mazak Optonics Corp., Schaumburg, Ill. "But it's an undue focus. It's as if, sitting in traffic, I think, 'If I could just drive faster, my commute would be shorter.' So I spend a lot of money to buy a really fast car, only to find I'm still stuck in the same gridlock traffic I was before."
The same can happen when buying a high-speed laser and not accommodating for part flow, be it within a product-oriented factory layout or a process-oriented job-shop layout. A shop should always analyze what the operator is doing while the laser cuts. For extremely high-speed cutting, an operator may continually need to finesse the feeds and speeds, the cutting aperture and gas pressure, as debris and other factors can cause slight changes to the focal point, requiring on-the-fly adjustments.
"Making the process faster means you need more operator utilization at the machine, where he's not doing anything else," Derango explains. "Can you really afford to have highly skilled labor run only one machine?"
Consider the following: Workers demand (and deserve) higher wages year after year; customers, thanks to globalization, demand and get lower prices. According to Derango, the most direct path to close that gap requires a thorough analysis of labor utilization to produce higher sales volumes with less effort. If a company invests in high-speed automated processes, only to find out his employees spend their days unclogging bottlenecks on the shop floor, financial troubles follow. Not only do they spend money on equipment, their labor costs actually rise.
WAYS TO UNCLOG
A laser cell's value-added time occurs when it cuts metal—seemingly obvious. Yet if a high-speed system isn't integrated properly, it can spend remarkably little time cutting. Two major "non-value-adding" points contribute to this: material handling (including raw sheet, finished parts and scrap) and tool change-out. Of the two, tool change-out represents the later development.
To avoid a nozzle change out, manufacturers compromise setup. They may use a generic lens that covers the widest range of material. Yet the laser may be using a little more gas than needed, increasing gas-consumption costs, and speeds may have to be reduced.
Automatic nozzle-lens changes, like automatic-tool-changers in the chip-making world, can cut tool-change time substantially. This allows manufactures to both minimize downtime while still use nozzles specifically engineered for material types and thicknesses. Each setup has optimized focal lengths, meaning the laser heads can cut faster for longer periods. "With this, you've found a way to be more productive, and [after the initial tool-change-system investment] it costs no more than the price of a new lens," Derango says.
Considering tool-change time also puts a broader view on time studies, Derango adds. It's no longer just about how fast a laser can cut; it's about how many parts can be completed within a certain time frame. One laser may cut a part 10 seconds faster than another, but the setups required for the faster laser over an eight-hour period may eat that time up and then some.
SMART AUTOMATION
Dobbs at Midwest Metal Products takes advantage of both paths of automation around its laser operation: automated material handling through FMS towers as well as automatic tool change out. "Our goal," explains Dobbs, "is to be able to handle a five- or 10-piece job as efficiently as we handle a 100-piece job."
Key to this, he says, remains the company's "manufacturing plan" that every job follows, from estimation through scheduling, production, post-process inspection and delivery. Most parts follow four primary paths through the shop floor, and each starts with a different cutting technology: a 4,000-watt laser, a 1,500-watt laser for thinner gauges, the turret for hole-intensive geometries and 3D forms and a saw for structural and other material.
The shop employs three shift operators, one for each shift, to man the two laser machines. Each operator has the experience to set jobs up and fine-tune focal points as necessary. Yet they only have limited intervention for many jobs, and managers want to keep it that way.
After a job comes in and the schedule and routings are put in place, it then goes to the foreman, who manages nesting offline through intelligent software. Next, operators download the program to the machine through the shop's fiber-optic network, select the material, then start the job, with little or no tweaking required.
Management ensures those experienced operators—one of whom has been with the company since it first purchased a laser nine years ago—spend their days with critical, complex jobs. The rest only should require minimal, if any, intervention. Today, thanks to FMS automation and efficient routing, the shop processes up to 1/4-inch mild steel plate, unattended.
VALUING SKILLED LABOR
As Mazak Optonics' Derango puts it, skilled labor often has too much value to manually change out a torch or move material to clear bottlenecks. "Again, that labor is getting more expensive every year—as it should. The automation, however, isn't."
In the coming years, skilled labor will only become more valuable. Most predict that, with the boomer generation retiring, literally millions of job openings will open up within the next decade. Says Derango, "you have to better utilize your labor as best as you possible can, especially considering what's about to come."
Editor's Note: Artwork courtesy of Mazak Optonics, www.mazakoptonics.com.
author: By Tim Heston