How Does the Progressive Die Stamping Process Work?

A coil of metal feeds automatically into the first station, and the strip advances a fixed distance after every stroke. Each station downstream performs its own operation until the last station cuts the finished part free. At Trans-Matic, we run 15 progressive die presses globally ranging from 60 to 500 tons of capacity. Bullet-shaped pilots enter previously pierced holes in the strip at each station, which keeps alignment accurate to a few thousandths of an inch as the strip moves.

What Types of Parts Can Progressive Die Stamping Produce?

Progressive die stamping handles both flat stampings and parts that need a deeper draw, which covers most small-to-midsize components used in high-volume assemblies. Automotive brackets, connectors, lawn equipment hardware, and plumbing and HVAC fittings are common examples. Material choice plays a big role in how those stamped metal parts perform once they're in the field, from fatigue resistance to how well they hold a finish. That's usually decided alongside the die design, not after it.

What Materials Work Best for Progressive Die Stamping?

Low carbon steel is the most common choice when it comes to metal forming materials, as it’s prized for its formability, strength-to-weight ratio, and cost. Stainless steel, aluminum, titanium, brass, copper, and bronze all run through progressive dies too, depending on what the finished part needs to do. At Trans-Matic, we process raw material up to 0.180 inches thick for these programs. Materials commonly run through progressive dies include: Low carbon steel, for high-volume, cost-sensitive parts Stainless steel, where corrosion resistance and strength matter Aluminum, for lightweight parts in power storage or battery applications Titanium, brass, copper, and bronze, for specialized strength, conductivity, or corrosion needs

How Is Progressive Stamping Different From Transfer Press Stamping?

Progressive die stamping runs a continuous strip through a single die and suits simple-to-moderate part geometries in thin-to-medium materials at high volume. It's the more economical choice for long production runs. Transfer press stamping loads individual pre-cut blanks and moves them between stations across multiple dies, which is better suited to larger, more complex, deep-drawn parts. Both methods sit under the broader umbrella of metal forming, and the right one depends on part size, complexity, and volume, not a single "better" option.

What Are the Benefits of Progressive Die Stamping?

The biggest advantage is speed at volume: a single die produces a finished part on every stroke, with minimal scrap and low labor input per part. High part-to-part repeatability also means uniform quality across a full production run, not just the first batch off the press. Progressive die stamping allows for: Fast setup and quick changeover between runs Minimal scrap thanks to tight strip nesting Lower labor cost per part than processes requiring manual handling between stations Consistent quality across thousands, or millions, of identical metal stampings

How Fast Can Progressive Die Presses Run?

Speed depends on the part and the tooling, but our progressive stamping presses run at up to 250 strokes per minute. Output ranges from as few as 7 or 8 parts per minute on more complex parts up to 1,500 parts per minute on simpler ones. That range is exactly why progressive die stamping fits high-volume programs so well. A single press can run for an entire shift without slowing down, and the part coming off the die at minute 400 looks the same as the one at minute one.

Can Progressive Die Stamping Support Custom Prototyping?

Yes. Progressive die programs almost always start with prototyping, since tooling built around an unproven design is expensive to fix later. Our custom prototyping services take a part from a rough sketch or CAD file through 3D visualization and feasibility analysis before any production tooling gets cut. Finite element analysis and rapid stereolithography catch design issues early, before they turn into a die that has to be reworked mid-production. Two in-house tooling rooms let our team move from prototype feedback to adjusted tooling without waiting on an outside vendor, through the same product development and prototyping team that builds the final production dies.

Why Does Precision Matter in Progressive Metal Stamping?

Because a progressive die runs the same operation thousands of times in a row, even a small tolerance drift compounds fast. Precision metal stamping depends on pilots holding strip alignment to a few thousandths of an inch at every single station, every single stroke. That precision matters most in applications like automotive and electric vehicle components, where a part that's slightly out of spec can affect how an assembly fits or performs downstream. It's also what makes high part-to-part repeatability possible in the first place, rather than a happy accident of a well-tuned press.

Eddy Current Testing for Drawn Parts

A deep drawn shell can look perfect and still carry a hairline crack near a radius. Eddy current testing finds many of those flaws in seconds, without cutting, coating or marking the part.

As a global metal stamping manufacturer, we use eddy current testing on safety-critical components as a deep draw stamping company in Holland, MI.

Here is how the method works and what it can and cannot see.

How Eddy Currents Work

An eddy current probe holds a coil carrying alternating current. When the coil comes close to metal, its changing magnetic field induces small circular currents in the part.

Those currents push back on the coil. The instrument reads that change as an electrical signal, as the NDT Resource Center explains.

Why Drawn Parts Get a Closer Look

Deep drawn parts at Trans-Matic Mfg Co Inc, Holland MI

Deep drawing stretches a flat blank into a cup, can or housing, and the wall does not thin evenly. Tight radii and deep walls are where splits and thinning tend to start, as we describe in how deep draw forming differs.

Good die and part design prevents most of these problems, a topic covered in designing for deep drawing. Inspection then confirms the result on parts where a failure would matter.

What a Crack Does to the Signal

A crack interrupts the circular path of the eddy currents and weakens them under the coil. The instrument shows a local change as the probe passes over the flaw, according to this guide to surface cracks.

The method is sensitive to small surface and near-surface cracks. Results appear right away, which suits repeat checks on production parts.

Calibrating Against a Known Flaw

Eddy current signals shift with many variables, so the equipment is set up on a reference standard first. That standard should match the test part's alloy, thickness and geometry as closely as possible.

Narrow notches cut by electrical discharge machining often stand in for real cracks. Signals from production parts are then compared with the known reference response.

More Than Crack Detection

The same instrument can measure thin material thickness and electrical conductivity. Conductivity shifts with heat treatment, so a check can flag a part that looks right but missed its heat treatment.

Work hardening from the draw also affects the reading. That ties the test back to material choice for stamped parts, since each alloy hardens differently as it forms.

Where Eddy Current Testing Falls Short

Only conductive metals can be tested, and the probe has to reach the surface being checked. Penetration depth is limited, so a flaw buried in a thick section may not show.

Flaws running parallel to the coil winding, such as some laminations, can go undetected. A rough surface finish can also add noise to the signal.

One Part of a Wider Quality Plan

Eddy current testing works best next to other checks. Our in-house non-destructive testing also includes vision testing and form tracing, listed with our other metal stamping capabilities.

Each method suits a different kind of flaw, which is why most programs combine more than one method.

Frequently Asked Questions

Can eddy current testing find flaws inside the wall of a drawn part?

It finds flaws at or just below the surface, but its reach into the metal is limited. Higher test frequencies give the best sensitivity to surface cracks, while lower frequencies reach deeper with less sensitivity.

Ferromagnetic metals such as low carbon steel need even lower frequencies to reach any useful depth. A flaw buried deep in a thick section may call for a different inspection method.

Does eddy current testing work on stainless steel, aluminum and brass?

Yes, it works on electrically conductive metals, including the low carbon steel, stainless steel, aluminum, brass and titanium Trans-Matic draws. Each alloy responds differently, so the test is set up on a reference piece of the same material.

Magnetic grades such as low carbon steel need lower test frequencies than nonmagnetic aluminum or brass.

Can eddy current testing confirm a part was heat treated correctly?

In many alloys it can, because heat treatment changes how well the metal conducts electricity. A quick conductivity check can catch a part that looks identical to good parts but skipped its intended treatment.

Trans-Matic coordinates annealing and heat treating through local finishing partners as part of its part finishing services.

What other non-destructive tests does Trans-Matic use?

Alongside eddy current testing, Trans-Matic uses vision testing and form tracing to check stamped parts without damaging them. These checks are performed in-house, next to secondary services such as crimping, boring, threading and automated assembly.

Using several methods helps cover flaws that a single test could miss.

Does the eddy current probe have to touch the part?

No, the probe does not need to contact the part, and very little surface preparation is required. The coil only has to sit close to the area being checked.

Keeping that gap and angle steady matters, because probe wobble can change the signal. For repeat checks, fixtures or automated scanners can hold the probe in position.

Plan Inspection Into Your Next Part

If a drawn part is safety-critical, ask about eddy current testing at the quoting stage. As a deep draw metal stamping manufacturer in Holland, MI, we can review your print and suggest the right checks.

Call Trans-Matic at (616) 820-2500 or request a quote online.

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How Does Eddy Current Testing Find Defects in Deep Drawn Parts?