Page 22 - MetalForming November 2022

NO CHOICE BUT TO
fed by feed lines or blank destackers— allowing metal formers to reduce their costs and become more price-compet- itive in the market. The same goes for domestic or offshore competition. Wen- zel notes that not only does automation turn no-run applications and idle press- es into productive stamping lines, but it also can improve the throughput of those lines currently employing manual labor to move material through—some- times dramatically, he says. And, plenty of hand-transfer lines still running are crying to be automated.
“Although it might not always appear that automated lines run more quickly than manually tended lines,” Wenzel says, “we know that while oper- ators often can hand-transfer parts very quickly (while a manager stands by with a stopwatch, for example), they can do so only for a limited time. Even- tually they slow down, and throughput becomes erratic. This, compared to automation which just runs and runs, continuously at the same speed and without pause.”
Therefore, Wenzel stresses that stampers, when evaluating the poten- tial return on investment of process automation, not only evaluate potential improvements in stroke rate, but also focus on total shift throughput.
“We typically see total throughput increase by 30 to 60 percent or more,” Wenzel says, “due not only to increased press stroke rate but to gains in process stability and improved quality. Uptime percentage is very high with automa- tion and plays a key role in increasing output.”
Supporting Wenzel’s ideals, a blog post from the automation experts at Toronto-based Blueprint notes that “the standard average of automation uptime we’ve observed is 92 percent.”
Note: The post goes on to say that while automation should run close to 100-percent on time, it often does not due to a lack of proper maintenance. It also stresses the need for manufacturers to leverage real-time data collection and analysis, dashboards, and analytics to deliver the data and information required to enable the predictive and
preventive maintenance that keep auto- mated lines running at their best.
Uptime Beats Stroke Rate
What can metal formers expect dur- ing their automation journeys? What are the common hurdles along the way?
“I find that expectations always hover lower than reality,” Wenzel notes. “We can calculate the expected improvement in strokes/min., for example, but it’s hard for clients to really trust the gained uptime by automating a press line compared to running it manually until they see it. Stampers often underestimate what the uptime will be with the automation, and overestimate what they believe the uptime is manually.
“I have a client,” Wenzel offers as an example, “whose automated press line actually experienced a reduction in strokes/min., yet shift throughput climbed significantly. Why? Because uptime beats stroke rate. When evalu- ating the potential ROI of automation,” he stresses, “do not underestimate the amount of downtime that actually occurs on a manually tended press line.”
Don’t forget, too, Wenzel adds, the potential to damage parts when hand- transferring them, whether along a press line or during end-of-line oper- ations. “I’ve seen manually tended lines where stampers experience a significant number of damaged, highly cosmetic parts from manual handling,” he shares. “Damaged parts represent lost revenue and wasted production time. Quality levels often can jump when adding automation to production lines.”
Case Study—Automating Hand- Transfer
“One of our clients,” Wenzel con- tinues, “an OEM manufacturer of con- sumer goods, recently reported signif- icant gains from automating a hand-transfer line where multiple oper- ators moved parts through multiple presses. First, a great deal of work in process ( WIP) accumulated between each tool/press. The first stage was coil-fed, the remaining all hand-trans- fer, and output averaged 200 parts/hr.
We added a larger-bed press and automation to the line, while contin- uing to coil-feed the first die station. The automation eliminated WIP and output doubled to 400 parts/hr. And, when stamping smaller parts, the com- pany retooled the line to stamp two out per stroke, so that output rose from 200 to 800 parts/hr.
“In addition, he continues, “while the reduction in manual labor due to the automation varies by job, on aver- age we helped this customer reduce the amount of labor related to material handling by 80 percent. We also elimi- nated lost production caused by the scrapping of cosmetically sensitive parts that experienced scratches and dents during hand feeding. This allows the manufacturer to now sell—for prof- it—thousands of parts per year that otherwise would have been scrapped.”
While automation obviously allows a manufacturer to do more with less, “let’s not forget that even where stam- pers can find operators, often we find that employees are aging out,” Wenzel says. “We’re often automating rigorous, strenuous manual tasks, which allows a company to then reassign older yet knowledgeable and experienced oper- ators to other less-strenuous roles, extending their working life.
“Don’t underestimate the safety and ergonomics benefits to automating,” he adds.
What are the Hurdles
...to implementing part-feed automation? “When you’re trying to add automation to presses running tooling not originally designed for automation,” Wenzel says, “often the parts must transfer at varying heights above the bolster for some die stations. While a simple chore for an operator, automation setups ideally require that part load and unload simultaneously occur at all die stations. Unless the stamper can adjust and modify the tooling, the automation must emulate an operator’s moves, limiting its oper- ating speed.”
Other concerns:
• Scrap must shed automatically, or
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