Deep Drawing: Process, Materials, and Tolerances

A deep-drawn housing part tears on its very first production run, even though the tool and drawing had already been signed off. Failures like this cost time and trust with the manufacturing partner, and the cause almost always comes down to one of three things: the material, the tool, or the part geometry itself.

In brief: Deep drawing is defined under DIN 8584 as tension-compression forming of a flat sheet blank into an open-topped hollow shape, without deliberately changing the sheet thickness. A blank holder prevents wrinkling during the draw. Deep-drawing steels like DC04, along with certain aluminum and stainless steel grades, are the materials best suited to it. There's no fixed minimum batch size: economics depend on part size, material, and the number of draw stages.

What Is Deep Drawing, and How Does the Process Work?

In deep drawing, a punch presses a flat sheet blank through a drawing ring, forming it into an open-topped hollow shape without deliberately changing the wall thickness. That absence of intended thickness change is exactly what sets deep drawing apart from related processes like stretch forming, where the sheet is deliberately stretched and thereby thinned.

A blank holder surrounds the punch and applies just enough pressure to let the sheet slide inward toward the drawing ring while still preventing wrinkles from forming. Rounded edges on both the punch and the drawing ring let the material flow over them without tearing.

How Is a Deep-Drawing Tool Structured?

A deep-drawing tool consists of three central parts. The punch shapes the part from the inside, the drawing ring forms the outer contour, and the blank holder guides the sheet during the draw.

Injection molding forms its entire hollow space at once, using a cavity created by two mold halves. Deep drawing works differently: the final shape comes from the relative motion of punch and drawing ring over the draw stroke. More complex geometries often take several draw stages, each with its own tool set, before the final shape is reached.

Which Materials Are Suitable for Deep Drawing?

The best-suited materials combine high formability with an even flow behavior in every direction, classically cold-rolled deep-drawing steels.

DIN EN 10130 standardizes the common deep-drawing steels as grades DC01 through DC07, with DC07 offering the highest formability as the so-called special deep-drawing grade. How well a sheet material actually behaves shows up in its vertical anisotropy. A good deep-drawing steel reaches a mean anisotropy value rm of at least 1.25, and the higher that value, the greater the achievable draw depth. Differences in anisotropy between sheet directions also cause wavy earing at the rim of the finished part, which usually needs trimming afterward.

Which Parts Are Typically Deep-Drawn?

Deep drawing suits thin-walled, rotationally symmetric or rectangular hollow shapes with even wall thickness particularly well.

Common applications appear in the automotive industry, measurement and control technology, aerospace, electronics, packaging, and sports and leisure equipment. Typical parts include housings and covers, sometimes combined with cast components, as well as containers, cups, and shells.

What Tolerances Are Achievable in Deep Drawing?

Depending on part size, material, and the number of draw stages, tolerances down to ±0.05 mm are achievable, with tighter values realistic more for smaller, simpler drawn parts than for large, multi-stage ones.

These part-specific draw tolerances complement the more general tolerance classes under ISO 2768, which apply to dimensions not directly affected by the draw itself, such as holes added afterward. Tighter-toleranced drawn parts usually mean more draw stages in practice, and therefore higher tooling and inspection cost.

What Volume Makes Deep Drawing Worth It?

There's no blanket minimum volume for deep drawing. Part size, the number of draw stages, material, downstream operations, and required inspections all significantly change the economics.

Each part needs its own, part-specific tool, so that investment has to pay off across the planned volume, much like other forming processes. Machining, by contrast, works without any part-specific form at all. We cover how tooling cost and per-part cost balance out over a component's full service life in more detail in our post on Total Cost of Ownership.

What Sets Deep Drawing Apart from Plastic Thermoforming?

Metal deep drawing and plastic thermoforming, which is colloquially also often called "deep drawing" (Tiefziehen), are two fundamentally different processes that can't really be compared.

Metal deep drawing forms the sheet through mechanical tension-compression without heating. Plastic thermoforming instead heats a plastic sheet first, then usually draws or presses it into a mold using vacuum or compressed air. Anyone specifying "drawn parts" in a technical inquiry should always state the material to avoid confusion with the plastics process.

What Should Buyers Check Before Sourcing Deep-Drawn Parts?

Anyone sourcing deep-drawn parts should spell out at least four points clearly in the technical inquiry:

• the material, including grade, e.g. DC04 rather than just "deep-drawing steel"

• the required tolerance class for the drawn contour

• the number of permitted draw stages and downstream operations

• the intended inspection method for wall thickness and springback

If any of these is missing, the manufacturer sets the parameters at its own discretion, which makes later deviations at incoming goods inspection more likely. Especially on first orders, a first sample before series release pays off, since tearing tendency and springback often only show up on the real part, not in simulation.

Frequently Asked Questions About Deep Drawing

What's the difference between deep drawing and stretch forming?

In deep drawing, sheet thickness stays largely unchanged as material flows into the drawing ring. In stretch forming, the sheet is deliberately stretched and thereby thinned, which suits different part geometries.

What's the difference between deep drawing and plastic thermoforming?

Metal deep drawing forms cold sheet metal through mechanical tension-compression. Plastic thermoforming heats a plastic sheet and draws or presses it into a mold. The two processes only share a common colloquial name.

Which steel is best suited to deep drawing?

Cold-rolled deep-drawing steels in the DC series (DC01 to DC07) under DIN EN 10130 are the standard, with DC07 offering the highest formability for especially complex drawn parts.

What tolerances are realistic in deep drawing?

Depending on part size and the number of draw stages, tolerances down to ±0.05 mm are achievable, with tighter values realistic mainly for smaller, simpler geometries.

What volume makes deep drawing worth it?

There's no fixed minimum volume. Part size, material, the number of draw stages, and downstream operations together determine when the part-specific tool pays for itself.

Conclusion: Deep Drawing Pays Off With the Right Material and Tooling Concept

Deep drawing remains one of the most economical processes for thin-walled sheet metal hollow shapes, provided material grade, draw stages, and tolerances are specified clearly from the outset. Buyers who nail these points down in the technical inquiry avoid tears and rework, and can compare quotes from different manufacturing partners realistically.

Line Up supports buyers through exactly this specification: from material selection through evaluating suitable manufacturing partners in the Far East to quality assurance on the finished drawn part. 👉 Schedule a no-obligation consultation and find out which tooling concept makes the most economic sense for your next drawn part.