6 steps to streamline the press brake department

Oct 14, 2024

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Gary Conner has seen it all. He spent decades as a lean manufacturing consultant, most recently with the Oregon Manufacturing Extension Partnership (OMEP), and before that, he spent years in metal fabrication, including time as a night shift operator and lead in what many consider the beating heart of any precision sheet metal shop: the press brake department.

He’s watched shops attempt to streamline flow in bending. They track movements and jobs in software, perhaps rearrange equipment to cut down that excess transportation (classic lean waste) and make better use of space, accumulate mountains of data—and end up putting the cart before the horse. That is, they miss low-hanging fruit and gloss over the lean manufacturing fundamentals that make any improvement meaningful, culturally and financially.

Conner discussed six steps to avoid this conundrum and ultimately set a good foundation for improvement in the press brake department. Over the years, he’s gleaned one immutable fact about improving throughput in bending—not processing more parts per hour, but the right parts, so that more jobs ship out the door in less time. At the end of the day, it all starts with the setup.

Conner recalled his early days working at a precision fabricator in Oregon. “I used to be the frustrated night shift operator in the press brake department.”

The brake department ran production work. It wasn’t running low quantities and prototypes. These were established jobs, with bend programs based on the shop’s available tools. Even so, many operators in production had their own opinions and preferences. They’d select different tools, perhaps arrange them in a different fashion across the bed, and tweak the bend program to their liking.

“I would come in, do my setup, and have it approved,” Conner recalled. “The quality people would sign off on the first article, and then I’d start running parts. The next day, the people running the day shift would say, ‘No, I don’t like that setup. I need to change that.’ There was no standardization. It was like we were reinventing the wheel with every setup. Eventually, everyone got together to establish a standard process, including a setup sheet that everyone could follow.”

Standardization establishes the first building block for the transformation. If setups aren’t consistent, neither is anything else in a press brake operation. Press brake operators can have preferences about which tools should go where. What’s ideal for one person might not be ideal for another—but what’s ideal for an individual doesn’t really matter. It’s about what setup works for everyone.

Conner added that this effort starts to address the cultural transformation needed for continuous improvement. Individual efficiency isn’t what customers are paying for; they’re paying for efficiency of the entire team, from cutting to bending and beyond. Ideas about setup (or anything else) are great to share, and many could be documented and established as best practices across the brake department and elsewhere. But people trudging forward silently and doing things their own way—even if it’s a better way—helps no one. Everyone needs to be on the same page.

Conner recalled visiting one fabricator that moved press brakes closer together to promote better part flow—a classic lean manufacturing strategy to minimize excess transportation. Jobs spend more time between processes than in them, so easing transportation from one machine to another seems like a logical strategy—right? As Conner explained, not necessarily.

Why exactly do jobs spend so much time between processes? Releasing a job too early is a contributing factor, but the root cause often has to do with batch sizes and setup times. He recalled one job at the Oregon shop comprising 40 different components. The customer demanded 600 a month.

Because many setups were so complicated, everyone aimed to minimize the number of them. And so, to maximize “efficiency,” operators relied on classic batch production. They produced 600 pieces of one component, then tore down and set up to produce 600 pieces of another component. They would repeat this 40 times, finally shipping the job in four to six weeks. Over that time, the work-in-process (WIP) built up on pallets and racks until the 600th part of the 40th component was formed. At long last, the entire job could be shipped.

All that WIP hinders cash flow and increases risk. Last-minute engineering changes can make those mountains of WIP obsolete. Rework—the worst kind of waste in custom fab—ensues. And managing all that WIP comes with its own inventory management costs.

The reason large batches dominate, of course, comes down to those arduous setups. But what if those setups weren’t so arduous and lengthy? As the steps that follow show, dedicating more resources to quick setup in bending actually leads to shipping more jobs (more revenue) during a given period—even if it means keeping a machine idle (more on this later).

In Conner’s case, educating the team about the benefits of smaller batch sizes didn’t occur all at once. In fact, the change was driven first by customer demand. “The customer told us, ‘We don’t want you to make 600 a month anymore. We don’t have room to store all that. We’d prefer you ship 150 a week,” Conner recalled. “So, we continued to make 600 and just hold the inventory as the shipping department sent out 150 a week. The customer caught on quickly. ‘No, that’s not what we meant. We want you to manufacture and deliver 150 a week. If we have an engineering change, we don’t want you to be stuck with inventory you can’t use.’

“So, we started making 150 a week, but the setup times were killing us. So we shortened those 36-minute setups to six minutes.”

How this happened involved some common setup reduction methods along with a little out-of-the-box thinking. People stopped focusing on how many parts a machine produced per hour and instead turned their attention to how quickly parts flowed through the entire shop.

Conner attributed some of the setup reduction to common lean tools like 5S. This included changeover and inspection tool organization (no more hunting for the right Allen wrench or caliper), as well as basic cleaning and maintenance—wiping tools, the brake bed, ensuring no stray metal shaving created divots in the tooling or workpiece.

It also involved standardized procedures (including setups); investing in duplicate tooling as needed (so no one needed to wait for the right punch and die to become available); and employing a water spider, who would stage tools in the exact order the operator needed for the next job, alongside a standard job jacket with clear setup instructions.

“The idea was that we never wanted operators to be more than 5 ft. away from anything they needed to set up the next job,” Conner said. “He was delivered everything he needed on a cart and nearby pallets.”

Other setup reduction tactics weren’t used at Conner’s Oregon shop, but they have worked well in other situations. Conner recalled working with a manufacturer with a diverse product line, and how brake personnel strategically designed one staged setup that could handle dozens of different products. The setup incorporated a range of precision and even homemade tools. Dialing it all in took a serious amount of time, but it was time well spent. After that, the brake could handle any part within the product family that came its way—no rearranging of tools required.

Of course, such an arrangement wouldn’t work at a custom fabricator in which a brake could bend thousands of different parts. At Conner’s Oregon shop, developing one staged setup just wasn’t practical.

Some setups simply took time, mainly because the shop formed some seriously complicated work. “I recall some of the worst ones having 26 bends in a single setup,” Conner said.

Here, the press brake team came up with an out-of-the-box solution. The department had five people operating five machines. What if one operator stopped producing parts and simply focused on setups—with only four machines producing at any given time?

Here’s how it would work: The setup person (who doubled as a water spider) would prepare the next job on an idle brake. He’d pull up the program, stage the workpieces and the tools, perform the tryout bends, inspect first articles, and have everything ready. Once a production operator finished the previous run on another brake, he’d move over to the newly set up brake and commence the next job. The setup person would then move to the idle machine to set up the next job. In this way, one person was always setting up while four people were always producing parts.

Conner chuckled. “When I proposed this to my boss, he said, ‘You must be smoking crack. Do you know what a press brake costs me? And you want me to basically keep one press brake idle?’”

Conner eventually convinced his boss to try the arrangement for a month, under one condition—that the shop wouldn’t lose a penny in production. “We typically ran about $800,000 a month through those five press brakes. Producing with just four press brakes, we didn’t drop in sales at all. And we gained 20% in capacity because we now had a free press brake. All you’d need is to hire someone to run the brake.”

Consider the math on this. The freed 20% capacity represents $165,000 of potential revenue a month, or $1.9 million a year. Not all jobs are equally profitable, and there’s no guarantee that the capacity could be sold, so $1 million flat might be more accurate. Still, Conner said, that’s plenty of money for hiring and training an additional operator. And if everything is standardized, organized, clean, and well documented, training becomes easier.

Eventually, Conner’s brake department took this concept in a slightly new direction. Instead of having one brake idle, setup personnel staged tools on a “dummy” press brake that duplicated the real press brake exactly. Specifically, they would stage punches and dies on mock-up rails, mark their exact position, then wheeled the dummy brake up to the machine. Operators called this “presetting.” When the operator finished the previous job, he’d unload the tools, then go to the dummy brake and simply slide all the punches and dies into place, after which the job was almost always good to go.

Nothing in the fab shop happens in a vacuum. Every decision a brake operator makes could affect “internal customers” downstream and “internal suppliers” upstream.

The cutting machine programmer should know which parts are sensitive to grain direction, which microtabs could interfere with press brake backgauges, and which parts might be sensitive to slight changes in material thickness. The last mentioned can affect where programmers place parts on a nest on certain materials, since thickness can vary slightly from one end of a sheet to the other.

Good communication helps part presentation in the bending department. Conner recalled a time when he and the punch programmer discussed challenges with a certain extremely tight-tolerance job that required slight setup adjustments at the press brake. Grouping all those parts on specific areas of a sheet was an option, but if they took that approach, they’d be giving up a considerable amount of material utilization.

So, they took another approach. Certain blanks were stacked and delivered in different places on a pallet, depending on where the part was in the sheet. Some pieces were in the “thin stack” and others were in the “thick stack.” Conner clarified that the thickness differences were extremely minute—just a few thousandths—but the programs had so many bends and the requirements were so tight, the stack-up errors after multiple bends would throw the part out of tolerance.

The part presentation strategy didn’t always work perfectly. So as a second check, Conner took an even simpler approach: He used a digital postage scale. He’d quickly place the blank on the scale and, depending on what the weight was, either run the part or stack it to the side. “I would run all the light parts, then the heavy parts, as a group.”

Weighing every part wouldn’t work in all applications and part sizes, of course, but the practice does show the importance of preparation before the first bend is made. In a sense, weighing the part is a “setup” task, ensuring the material thickness is within tolerance and the precision bending sequence will run without a hitch.

Conner recalled working the night shift next to a brake operator, back in the shop’s batch manufacturing days, when each would produce hundreds of the same parts over a shift. He noticed that his co-worker took more time—a lot more time—and he soon found out why. If a job needed to be bent to within 0.015 in., he’d bend within 0.007 in.

Conner chuckled. “He’d measure every third part and make a slight adjustment, always chasing that next thousandth [of an inch].”

There’s an excessive cost of quality here, but Conner saw opportunity in this situation. When he eventually became press brake department supervisor, he made sure to assign all the precision work to that conscientious operator.

It’s all about having people in the right seat on the bus. Work is work, and sometimes people need to just get a less-than-desirable job done. But if someone enjoys a particular task, they should do as much of it as they can.

Conner spent decades as a lean consultant. As a brake operator, he worked in a world before press brakes with automatic tool change, mature offline bend simulation technology, and sensors that detect and correct for forming inaccuracies in real time.

New technology certainly opens new productivity opportunities, but press brake departments still employ people with different talents and who work in different ways. One fact, however, hasn’t changed over the years: When it comes to better bending, it all starts with the setup. If most setups remain inconsistent and challenging, so will the entire press brake operation.