A large-format cartesian printer built for cementitious material extrusion at scale.
M3-CRETE is an open-source hardware project for building a concrete 3D printer from standard, commercially available components. The system is purpose-built for layer-by-layer extrusion of cementitious materials — no heated beds, no proprietary toolchains, no vendor lock-in.
M³ = Mobile · Modular · Meter³
Developed by Sunnyday Technologies.
| Spec | Value |
|---|---|
| Open BOM component target | Under $5,000 when self-sourced and self-assembled, where current commodity pricing and substitutions allow |
| Build footprint | Sub-1 m³ — fits on a standard US pallet (48×40 in) |
| Printhead weight | ~1.5 kg |
| License | CERN-OHL-W-2.0 |
Most concrete 3D printers are either proprietary industrial systems or one-off research machines tied to specific institutions. M3-CRETE targets the space between — an open, buildable, field-serviceable printer design that teams can replicate, maintain, validate, and scale independently.
- Hardscape and site elements
- Agricultural and industrial processing infrastructure
- Urban water control and drainage components
- Construction and infrastructure parts
- Modular elements for rapid deployment and disaster response
- Digital formwork and precast molds
These are applications where repeatability, throughput, and reliability matter — and where accessible hardware can have the most immediate impact.
The frame is engineered closer to CNC machine standards than desktop 3D printers: rigid, durable, and precise. Every structural component uses standard aluminum extrusions and commodity hardware. If something breaks on a job site, you source a replacement locally — not from a single-source vendor.
With an efficient frame design, the drive system uses motors comparable in size to hobbyist 3D printers while delivering sufficient torque for the full gantry. This provides a significantly safer working envelope for students, researchers, and craftsmen compared to heavy industrial machinery.
Concrete cures by hydration — a chemical reaction — not by melting and cooling. This eliminates roughly 25% of the hardware cost and complexity associated with conventional FDM printers (heated beds, hot ends, cooling fans), resulting in a mechanically simpler, more energy-efficient, and more reliable machine.
Many non-structural components — brackets, guides, and enclosure parts — are designed to be 3D-printable using an existing M3-CRETE unit or any FDM printer. This reduces replication cost and simplifies field replacement. Scalability is a feature, not an afterthought.
M3-CRETE runs on established open-source toolchains. No proprietary software required.
| Layer | Compatible Tools |
|---|---|
| Firmware | Marlin, Klipper |
| Slicers | Cura, OrcaSlicer, PrusaSlicer |
| Controls | Standard stepper drivers, common control boards |
| CAD/CAM | Any tool that exports STL, OBJ, or 3MF |
Standard G-code workflows provide full, transparent control over toolpaths, layer heights, and extrusion parameters.
Firmware configurations are maintained separately: M3-CRETE-FIRMWARE
M3-CRETE/
├── CAD/
│ ├── M3-2_Assembly.step # Full assembly (99 parts, 13.5 MB via LFS)
│ ├── m3_2_assembly.py # CadQuery assembly generator (source of truth)
│ ├── self_check.py # 5-gate automated validation harness
│ ├── kinematics_eval.py # Structural analysis (deflection, torque, belts)
│ ├── Custom/ # 3D-printable brackets (STEP + STL)
│ ├── Components/ # OpenBuilds parts library (CC BY-SA 4.0)
│ └── Advanced/ # Extended parts (C-beam, joining plates)
├── bom/
│ ├── data.json # BOM source of truth (62 parts, v2.5.0)
│ └── index.html # Interactive BOM viewer (bom.m3-crete.com/bom)
├── firmware/ # Klipper configs (kinematics, steppers)
├── blog/ # Build logs and project updates
└── config.js # Model variants (M3-1, M3-2, M3-4)
This project uses CADCLAW — an automated validation framework for STEP assemblies developed during this project. The assembly script generates geometry, the self-check harness validates it (inventory, interference, adjacency, dimensions), and the kinematics module analyzes structural performance. This workflow caught 53 interferences and reduced the STEP file from 70 MB to 13 MB.
See the CADCLAW repo for the generalized, reusable framework.
M3-CRETE is a hardware platform — it does not prescribe a specific concrete mix. The system is designed to work with a range of cementitious formulations optimized for layered extrusion, including OPC, LC3, and specialty blends.
For AI-driven mix design optimized for 3D printing, see CEMFORGE™ — a machine learning formulation engine trained on validated 3D-printed cementitious specimen data, designed to generate candidate mixes and supported performance predictions where sufficient data exists.
M3-CRETE is in active development. Current focus areas:
- Finalizing the open BOM and build documentation
- Validating open assembly notes and build sequence
- Establishing firmware profiles for concrete-specific extrusion parameters
Interested in contributing design feedback, supplier corrections, or field-build notes? Open an issue or start a GitHub discussion.
M3-CRETE is provided as-is for educational and development purposes. Concrete 3D printing involves heavy machinery, cementitious materials, and electrical systems that pose safety risks. Users assume all responsibility for safe design, construction, and operation of any system built from these files. Sunnyday Technologies makes no warranties regarding fitness for any particular purpose and assumes no liability for injury, damage, or loss resulting from the use of these designs. Consult applicable local building codes, electrical codes, and safety regulations before construction or operation.
Any AC mains wiring, control-box integration, grounding, bonding, overcurrent protection, disconnects, emergency-stop power circuits, facility connection, inspection, or code compliance work must be performed by qualified personnel, a licensed electrician where required, or a qualified control-panel shop.
The public M3-CRETE files may identify electrical interfaces, low-voltage controls, and component references, but they are not AC mains wiring instructions and are not a substitute for applicable electrical codes, authority-having-jurisdiction review, or professional electrical judgment.
See DISCLAIMER.md for full details.
This project is licensed under the CERN Open Hardware Licence Version 2 — Weakly Reciprocal (CERN-OHL-W-2.0).
You may use, modify, and distribute this design under the terms of that license. Modifications to covered files must be made available under the same license. This project includes no warranty of any kind.
Dual License Notice: V-Slot component CAD models in CAD/Components/ are based on OpenBuilds designs and are licensed under CC BY-SA 4.0. All other project files (custom parts, BOM viewer, firmware configs, documentation) are licensed under CERN-OHL-W-2.0.
See LICENSES/ for full license texts.
| Resource | Description |
|---|---|
| Convergence Engineering whitepaper | Methodology paper that uses M3-CRETE as a public case study; introduces the time to silence metric. CC BY 4.0 preprint, Zenodo. |
| Sunnyday Technologies | Parent company — concrete 3D printing and engineered cementitious composites |
| M3-CRETE Project Page | Hosted project overview and Sunnyday contact path |
| CADCLAW | Automated STEP assembly validation — extracted from this project |
| CEMFORGE™ | AI-powered concrete formulation platform by Sunnyday Technologies |
| M3-CRETE Firmware | Firmware configurations for Klipper |
Nicholas Sonnentag (ORCID 0009-0002-1897-384X) — mechanical engineer, founder of Sunnyday Technologies. M3-CRETE is designed and maintained by Nick; CAD iteration is LLM-assisted but the engineering judgment, component selection, build decisions, and direction are his.
- LinkedIn: Nicholas Sonnentag
- Email:
info@sunn3d.com
If you use M3-CRETE designs in research, a build, or derivative work, please cite:
Sonnentag, N. (2026). M3-CRETE: Open-Source Concrete 3D Printer.
Sunnyday Technologies.
https://doi.org/10.5281/zenodo.19647436
For the methodology paper that uses M3-CRETE as a public case study, cite:
Sonnentag, N. (2026). Convergence Engineering: Commissioning Autonomous
Software by Measuring the Rate at Which Novel Failures Trend Toward Zero.
Sunnyday Technologies. https://doi.org/10.5281/zenodo.19863080
A CITATION.cff file is included for automated citation tooling.
We welcome issues, pull requests, and design feedback. If you're building a concrete printer or working with cementitious extrusion, your field experience is valuable — open an issue or start a discussion.
Contact: info@sunn3d.com