It's Simple: Modifying stroke length for higher productivity, longer die life and reduced maintenance-related downtime

April, 2025- Pioneering architect Ludwig Mies van der Rohe spearheaded the minimalist approach and coined the phrase “less is more.” The well-known adage also describes stroke length, a foundational element to the operation of a stamping press. Whether parts are hand fed or processed in an automated line, a shorter stroke provides advantages that are often missed in press operations.

“Manufacturers either overlook or don’t always have a good understanding of the impact high dynamic forces have on the machine, tooling and part quality,” says Zeb Hassell, sales and marketing, Sangiacomo Presses Americas LLC. “Most people underestimate the consequences of stamping with a longer stroke than is necessary.”

In a vertical industry that is more than a century old, entrenched ideology can contribute to this mindset. Sangiacomo President Rene Zwahlen says legacy operations can trap job shops in a stagnant routine.

“A company may start out by running a prototype or short-run job on a stamping press but when production requirements change, stampers sometimes do not think about how to further optimize the process.” This is often due to a make-it-work mindset. The machinery builder encourages customers “to first look at a simpler solution. We show them how modifying stroke length can deliver big dividends,” Zwahlen says.

More often than not, stroke length is dictated by the visible benefits it affords the operator. With a manual/hand-fed operation for example, a longer stroke length provides more vertical space to maneuver blanks and parts and more visual access to the dies. It also means more room for adjustments and repairs along with use of a wider variety of tools.

DATA POINTS

“However, analysis will show that a longer stroke reduces cutting and forming time and increases dynamic forces,” Hassell says. “It can also result in a significant amount of wasted time and motion, which leads to inefficiencies in throughput and quality. More time is actually spent on the ram traveling to the working portion of the stroke than in the working portion of the stroke.”

Choice of stroke length also impacts automated stamping processes. Typically a stamping process is automated to increase production rates but there are other benefits. “Unlike a manual or hand-fed operation, automation means operators have less influence on production efficiencies,” he continues. “This allows the machinery to play a larger role in determining those outcomes. This is when the use of the shortest stroke really starts to make a difference, especially when jobs are producing hundreds of thousands or even millions of parts.”

Sangiacomo’s staff points potential buyers to the data. If a stamping process uses a stroke length of 10 in., shortening the stroke by half [5 in.] can increase forming time by 42 percent, decrease impact velocity by 30 percent and acceleration by 50 percent. This equals more time for forming and results in higher quality parts.

Decreased impact velocity extends tool life and minimizes the need for repairs. Decreased acceleration means less wear on the press and less maintenance-related downtime. “Considering the hidden costs of using longer strokes, the most optimal stroke is always the shortest stroke,” Hassell says.

To help customers identify the most effective stroke length, Sangiacomo looks at several factors. A job shop or fabricator should consider the time needed for material feeding, lubrication and how much clearance a part requires to move from station to station. Additional factors include material thickness to be stamped and how much energy the forming process will require.

Sangiacomo’s adjustable stroke mechanical presses allow stampers to optimize stroke length for a range of applications.

A shorter stroke length contributes to increased forming times and higher quality finished parts.

Decreased impact velocity extends tool life and minimizes the need for repetitive sharpening and repairs.

Sangiacomo’s adjustable stroke mechanical presses allow stampers to optimize stroke length for a range of applications. 

ADJUSTABLE STROKE LENGTH

The press manufacturer’s servo press technology and unique adjustable stroke mechanical presses help job shops optimize the machine to the application versus “making jobs run according to the presses they have,” according to Hassell.

Its customized and standard press solutions  mechanical or servo-driven C-frame and straight-side are engineered to meet customers’ needs. Sangiacomo also designs complete stamping lines that include coilers, straighteners, feeders, lubrication systems and part handling.

Conventional fixed-stroke mechanical presses restrict companies to a non-adjustable stroke length. “For contract manufacturers with diverse needs, this potentially translates to lost productivity, efficiency and underutilized floor space,” says Hassell. “Both our servo technology and adjustable stroke mechanical presses remove these boundaries and equip metal stamping operations with multiple forming capabilities, including blanking, coining and drawing under a single press.”

Consolidating multiple machines into one press frees up valuable floor space. Premature press wear, repetitive tool sharpening and subsequent recurring maintenance are minimized. Shorter, more efficient stroke lengths increase overall efficiency and productivity. Using the optimal stroke also ensures superior quality for stamped parts.

“Metal stampers should look to the future when considering new stamping presses,” Hassell says. “What may be optimal for one process can differ for future jobs or requirements. Having equipment that can accommodate evolving needs is essential to remaining competitive in the modern metal forming industry.”

Nearly all metal stamping operations can benefit from using the shortest stroke length possible.