SPI

Technology

Selective Paste Intrusion, or SPI, is a novel method for 3D concrete printing that was first used at Scawo3D in 2022. Today, we invent, advance and produce SPI technology for and with you.

Our SPI technology applies cement paste onto loose aggregate beds through automated print heads. This approach completely eliminates formworks whilst achieving structural integrity and surface quality across all sorts of applications – from design through architectural and structural components.

The layer-by-layer construction process deposits cement paste, creating intrusion patterns that bond with underlying materials. Each layer builds upon the previous foundation, enabling complex geometries whilst maintaining dimensional stability throughout the manufacturing cycle.

Post-printing procedures involve removal from the particle bed followed by curing under controlled conditions. Components undergo cleaning processes to reveal surface characteristics, with finishing treatments available depending on application requirements and environmental exposure.

The manufacturing process accommodates diverse component sizes within our print chamber, handling everything from decorative elements to structural components. Production scheduling adapts to project timelines whilst maintaining consistent output standards across all manufactured elements throughout the fabrication process.

Our SPI facility

Since 2022, our large format SPI facility is operational. The SPI printer itself features a particle bed measuring 4 x 2.5 x 1.5 m³ allowing for the production of architectural-scale components. Multiple silos store different aggregates, filling the particle bed, as well as different cement types that are fed automatically to the cement mixer and printhead.

Step by Step

1. 3D File Preparation

a) 3D modelling
When modelling your 3D file, make sure you follow our guidelines.
b) Slicing
Send us your file in one of the 3D formats and specify the desired dimensions, material and finish.
c) Particle bed arrangement
Go through our offer and make sure everything is according to your needs.

2. Selective Paste Intrusion

a) Dry particle bed
SPI's advantage lies in its particle bed filled with loose and dry concrete aggregate. Unlike other binder jetting technologies, no binder is mixed into the aggregate.
b) Application of cement paste
Onto the loose particle bed, Scawo3D's printhead applies cement paste with high precision. The perfect cement mixture allows for an accurate intrusion to connect with the previous layer.
c) Aggregate layer
After one applied layer of cement paste, another layer of aggregate is deposited. The process is repeated layer by layer until the print job is complete.

3. Unpacking & Finishing

a) Unpacking
After an initial period of curing inside the constraints of the particle bed, the loose aggregate surrounding the part is removed.
b) Retrieval & cleaning
The part is retrieved from the particle bed and cleaned. Depending on the requirements, the part is stored under standardised conditions.
c) Finishing
In a final and optional step, the part receives a finish. Depending on its later usage – for example in- or outdoors – it can be sanded, sealed or coated.

SPI material mixtures are highly flexible and capable of featuring a multitude of aggregate and cement types. Choose from our catalog of tested materials or configure your own mixture with our help.

Lightweight expanded clay

Lightweight expanded clay

Quartz sand

Quartz sand

Are you interested in a specific material or in developing your own? Let us know!

Our machines are tailored to your production's requirements. Get in touch to start specifiying!

Bold ideas deserve bold solutions. We turn your vision into concrete reality.

Is your stair design too complex for conventional production? Get in touch!

Get in touch with us to print your file in 3D concrete.

Contact