Wondering about the difference between a “high-speed” stamping press and one that’s just pretty darn fast? Or maybe you’re thinking about adding some accessories to your existing press – high-speed or otherwise – that will improve part quality?
To get some insight, Stamping Productivity sat down for a chat with René Zwahlen, president of Huntsville, Ala.-based Sangiacomo Presses Americas LLC. Zwahlen answered the questions posed, shared some details behind the company’s history and offered a few thoughts on the health of the stamping industry, a market sector he has served for more than three decades. Therefore, if you choose to read on, we’re sure you’ll find his insights valuable, no matter what kind of parts you make.
STP: To start, explain your role with Bruderer and how the company differs from Sangiacomo.
Zwahlen: Bruderer is a Swiss manufacturer of stamping presses. They do one thing – high-speed, high-precision presses – and that’s all they do. Alois Rupp began selling Bruderer machines in the United States in the 1960s and eventually formed Bruderer Machinery, the U.S. distributorship. Because of the demand here, Bruderer Switzerland opened a manufacturing plant in Huntsville that built machines specifically for the U.S. market, including models outfitted with U.S.-specific controls, such as Wintriss.
When the tech bubble burst around 2001, it hit the high-speed stamping industry hard. Bruderer closed the Huntsville plant, and Rupp bought the land, building and inventory to start a rebuild operation. That’s what I oversee today – we rebuild Bruderer machines here, keeping many of the skilled workers who’d been part of the manufacturing operation.
Then, in around 2014, Rupp was approached by Sangiacomo. He saw an opportunity to offer a machine with an adjustable stroke and good quality, comparable in some ways to Bruderer though not at the same level. He created Sangiacomo Presses Americas as the U.S. distributorship for Sangiacomo, which has its factory in Italy. Rupp owns both distributorships, and I work across both companies in different capacities.
Some presses today achieve 2,000-plus strokes per min. (spm), but when does a press qualify as “high-speed?”
There’s no clearly defined threshold. Historically, back in the 1940s, a high-speed press was simply an automated press – something with a feeder – because most of the industry was still running conventional hand-fed presses. People often quote 100 spm as the line, but that number came from the fact that early automated high-speed presses simply didn’t run slower than 100 spm. If you were over 100, you were in a different category.
But technically speaking, high speed has nothing to do with a specific stroke rate. It’s about when dynamic forces start to matter – when velocity and acceleration introduce forces that don’t exist at slow speeds. If you move something slowly, it’s basically static. As velocity increases, dynamic loads increase sharply.
The two things that govern this are mass and velocity of the moving ram. A large press with a long stroke may never run at 100 spm, but it still faces significant dynamic loads. Meanwhile, if you’re running tiny electronic connector parts at a very short stroke, you might run thousands of strokes per minute because the mass is low and the distance is small. It’s a hyperbolic relationship. Once a press is operating near the limits of the dynamic forces it can withstand, that’s when it becomes a high-speed press.
Do most shops understand this distinction and buy the right equipment for their needs?
Unfortunately, no. And even when you explain it to them, most don’t truly grasp it, nor do they see how these concepts translate into money. Tooling must keep up. Lubrication must keep up. Everything changes.
The fact is most people still buy presses in a very traditional way. They celebrate improvements that really are low-hanging fruit – things any high schooler could spot, like tightening brackets. High-speed stamping requires a fundamentally different understanding of stamping, and traditional toolmakers often lack that background.
Do shops tend to buy bigger, heavier presses “just in case” they need to run some big parts, even if much of their work is small?
Yes, and it causes problems beyond simply limiting their speed. You rarely hit the perfect match unless you design a machine for one specific part. But you can get very close. Adjustable stroke is a big part of that.
On servo presses, people learn this because they must program the motion. If they run a servo in full revolution mode, they’ve basically turned it into a mechanical press with a long stroke. The first thing they do is switch to pendulum mode and shorten the stroke. That’s where the gain comes from.
People think that servo technology is responsible for this magic, but in most applications, the benefit is simply stroke reduction. A mechanical press with an adjustable stroke does the same thing.
With Sangiacomo presses, if I have a small part that only needs a small amount of stroke, can I shorten it and get into high-speed territory?
Exactly. For example, a press with a 1-in. stroke might have a 200 spm rating. If you reduce it to a 0.5-in. stroke, you might get 300 spm. But if your press has a fixed stroke, you’re capped at that lower value. You can’t push the press beyond its dynamic limits. With adjustable stroke, you aren’t abusing the machine – you’re reducing the dynamic forces and gaining speed.
On the Bruderer side, what’s new in the high-speed realm?
When you get into high speed, everything – not just the press – must keep up. That includes the feeder, tool protection, electronics, lubrication, scrap management and part handling. You can’t have someone hand pack parts coming out at 1,000 spm. Automation must extend far beyond the press. If you add high-speed quality requirements, you must also automate sample cutout and inspection.
Bruderer has long offered the PSS-40 vision inspection system, which inspects a continuous strip and can trigger a fault. They later added a cutout station that could notch out defective parts but left a gap in the carrier strip. The newest system takes it further: It cuts out the defective part – including the portion of the carrier strip – then laser welds the strip back together, so the progression is maintained. The operator never sees gaps in the reel.
Last question – how’s business?
It’s okay, but slow. Tariffs have impacted Bruderer Switzerland, so our equipment and parts are currently at a premium. We’re hoping those costs come down.
The broader economy has cooled. There was a lot of hype around electric vehicles. However, automakers backed off, leaving many suppliers stuck with specialized equipment nobody needs right now. At a recent Precision Metalforming Association conference, the CEO of Martinrea International Inc., a major Tier 1 automotive supplier headquartered in Vaughan, Ontario, told the audience, “When you buy equipment, make sure it’s flexible.”
Adjustable stroke presses are the perfect example. Many suppliers bought highly specialized systems because their customers told them they’d be building millions of EVs. Now those programs are cancelled, and they’re stuck. Workforce pressure is easing, too. The desperation you saw a couple of years ago seems to have cooled off. With that in mind, I’m very optimistic about the industry, at least in the near future.
MSangiacomo Presses America LLC
