Buildability
Buildability is the ability of a freshly deposited mix to retain its shape and carry the weight of subsequent layers without excessive deformation, buckling or collapse.
Updated
Buildability is the ability of a freshly deposited mix to retain its shape and carry the weight of subsequent layers without excessive deformation, buckling or collapse. It is the counterpart to extrudability: a mix stiff enough to stack well is usually harder to pump, and the workable window between the two is narrow.
In practice
Failure during printing takes two forms. Plastic collapse occurs when the stress at the base exceeds the fresh material's strength, and shows as bulging in the lower layers. Elastic buckling occurs in tall, thin walls whose stiffness has not developed fast enough, and shows as lateral waviness. Which one governs depends on wall geometry and print rate, so a mix that stacks a thick block may still fail on a slender one. Buildability is improved by raising early stiffness, through thixotropic additions, accelerators or a lower water content, and by print strategy: shorter layers, longer cycle times, or dividing tall elements into stages.
Related terms
- Green strength — the fresh-state strength that buildability draws on.
- Extrudability — the competing requirement that the mix flow through the nozzle.
- Layer cycle time — the interval that gives each layer time to stiffen.
Frequently asked questions
- How is buildability measured?
- There is no single standard test. The most common laboratory approach prints a straight wall or hollow cylinder continuously until it fails, and records the number of layers or the total height reached. Results are only comparable when nozzle size, layer height, layer cycle time and ambient conditions are reported alongside them, since all four change the outcome.