concrete formwork · Exposed concrete formwork

exposed concrete formwork using 3D printing

The formwork facing determines the surface finish

With exposed concrete, the concrete surface remains visible, and every imperfection in the formwork can later be seen in the component. Mach-3D manufactures formwork and formwork inserts for special components, sample surfaces and one-off pieces – from a single part, with no need for tooling.

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SB 1 to SB 4Fair-faced concrete classes according to DBV/VDZ
900 × 900 × 1000 mmenclosed build space
from 1 piece onwardsno minimum order quantity

As of September 2026

In short: A 3D-printed formwork is suitable for exposed concrete if the formwork skin is post-treated. Raw printed surfaces show a fine layer structure that is reproduced in the concrete. When smoothed or sealed, the mould produces a smooth, uniform surface. Its strength lies in special components, sample surfaces and small series, not in mass production.

Content

  1. What makes formwork into exposed concrete formwork?
  2. Which exposed concrete class is achievable?
  3. Which formwork sheet suits which result?
  4. Intentional texture instead of a smooth surface
  5. Where the printed formwork does not fit
  6. Conclusion

What makes formwork into exposed concrete formwork?

Architectural concrete is concrete whose surface remains visible after the formwork is removed and is part of the design. In Germany, this is regulated by the Architectural concrete information sheet by DBV and VDZ. It divides areas into four classes, SB 1 to SB 4, and describes requirements for texture, porosity, colour uniformity, flatness, and working and formwork joints for each class.

For the formwork, this means: It is not the supporting structure that is decisive, but the formwork skin, meaning the surface that comes into contact with the fresh concrete. Its smoothness, its absorbency and its joints are replicated one-to-one on the structural element. An absorbent formwork facing results in darker, more matt surfaces with fewer pores, while a non-absorbent one produces lighter, smoother surfaces with a tendency towards more pores. Plastic is one of the non-absorbent formwork facings.

Which exposed concrete class can be achieved with printed formwork?

That depends less on the pressure than on three things: the post-treatment of the formwork skin, the position of the joints and the workmanship in the factory. No reputable person will therefore guarantee a specific class solely for the form, because the concrete mix, release agent, compaction and stripping time also play a part.

What we can influence and openly address:

  • Layer structure: FDM-printed surfaces have visible layer lines. For SB 1 and SB 2 (low to normal requirements), this is often uncritical, but for SB 3 and SB 4, the surface must be smoothed, filled, or sealed.
  • Fugen Up to 900 × 900 × 1000 mm, the mould is produced in one piece, meaning without a formwork joint. We divide larger moulds so that the joint is located on an edge or within an intentional shadow gap.
  • Sample area: The information leaflet recommends trial areas for higher classes. A printed form is precisely suited for this: a test piece with the actual formwork skin before the production mould is built.
Structurally forming formwork insert next to the finished precast concrete element with relief
Technical representation: The formwork facing determines every edge of the subsequent concrete surface.

Which formwork sheet suits which result?

formwork skinConcrete surfaceTypical application
Printed, untreatedfine line structure visibleconcealed surfaces, SB 1, intentional ribbed appearance
Printed, sanded and sealedclosed, even, brightnon-standard components, sample areas, small batch runs
Printed with an elastic insert (TPU)texture, relief, undercutLogos, textures, see structural matrices
Coated wooden boardsmooth, tile joints visibleflat surfaces, standard formwork
Steelvery smooth, very dimensionally stableongoing large-scale production in the precast plant

For the rigid formwork in concrete, we primarily use PP and PP-GF one: chemically resistant in alkaline fresh concrete (pH 12 to 13) and with low surface energy, which makes demoulding easier. For moulds stored outdoors, ASA. The full material overview is on the page concrete formwork.

Intentional texture instead of a smooth surface

Fair-faced concrete does not have to be smooth. Board-marked textures, grooves, exposed aggregate finishes, lettering or a company logo are created via the formwork skin. Traditionally, this requires a matrix and a master model. When printed, the structure is created directly from the CAD file, even as a one-off. Details on this can be found on the page structural matrices.

Where printed formwork is not the right choice

To be honest: For large, flat wall surfaces, panel formwork is more cost-effective. For many hundreds of casts of the same geometry, steel remains the first choice. And for the highest exposed concrete classes, post-treatment of the formwork skin is mandatory, which takes time. Printed formwork plays to its strengths where geometry is complex, the quantity is small and the deadline is tight.

Conclusion

A 3D-printed exposed concrete formwork works if the form lining is suitably post-treated and the joint is planned in. It neither replaces panel formwork for flat walls nor steel moulds for large-scale production. For special components, sample areas according to the exposed concrete code of practice and one-offs, it is the fastest route to the finished mould: from a single part, with no tooling costs, manufactured in Altenholz near Kiel.

discuss exposed concrete project

Send us a STEP, STL or a drawing and the required fair-faced concrete class. We will tell you which formwork skin is needed for this and whether the printed method is suitable.

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Continuing with concrete formwork

Concrete formwork construction overviewAll services, materials and the comparison with steel, wood, EPS and silicone.formerPenetrations, ducts and openings in the precast element, reusable or lost.structural matricesReliefs, logos and surface structures without die tooling.