Inspection of printed structures

Introduction

3D printing in construction covers several technologies (mainly layer-by-layer extrusion and processes with binders) applied to the manufacturing of elements and buildings. Among the potential advantages noted in the literature are the reduction of execution times, less dependence on labor and a more efficient use of materials, with the possibility of reducing waste; However, recent academic reviews emphasize that the comparative evidence of costs and productivity continues to be case-dependent and that the technology "has not yet reached its full potential."[1][2] In particular, various analyzes point out that the mere printing of the envelope does not resolve time- and cost-intensive items of work—such as reinforcements, installations and, above all, finishes—which limits the overall competitiveness of the process compared to conventional methods in many scenarios.[2] Based on these limitations, over the years In 2020, proposals have emerged that seek to automate additional tasks beyond deposition - configuring a "second generation" - through robotic platforms that integrate printing with complementary operations (handling, drilling/cutting, placing or inspection) and the use of sensors and AI, with the aim of improving the efficiency of the process.[1] As an example of this second approach, Evocons develops a multifunctional robotic platform that integrates concrete 3D printing with other automated operations aimed at accelerating the process and the finishes. In 2024–2025, various media reported projects and demonstrations in Spain, including the inauguration of a building built with 3D printing, robotics and artificial intelligence with automated finishes and certification in accordance with Spanish regulations.[3][4][5] This development is associated with patent EP3733354B1.

History

The technological development related to this technique began in the 1960s, with the pumping of concrete and isocyanate foams.[6] At the end of the 1990s, experiments began with the construction of 3D printed houses by extruding concrete from a computer-controlled robot and in 2014 the first 3D printed house was made on the banks of the Amsterdam canals.[7][8] This house is not was 3D printed in its entirety, but the pieces of it were printed separately and later put together to create the final structure of the house. The main construction material was bioplastic, a type of plastic derived from plants or other biological materials instead of petroleum.[9][8].

Introduction

History

Advantages

• - Possibility of providing a high level of detail and ornamentation to the construction, unlike buildings built with concrete.[8][20].

• - Unlimited design possibilities: ease of customizing each part of the house according to the client's needs and tastes.[8].

• - Sustainability: because 3D printing is an additive construction model, the raw material is converted directly into the final material. Construction materials are used more and the need for transportation is reduced.[8][10].

• - Reduction of waste because molds are not needed to pour the concrete[21].

• - Economic benefits: for the reasons mentioned above, the cost of materials is greatly reduced, as well as the cost of transportation and labor, which is reduced by up to 95%. It is estimated that in total the price is reduced by 35%.[22].

• - The complexity of manufacturing does not increase the cost. Because the cost is the same for building simple or complex shapes, complicated structures can be created without investing as much money as a more traditional construction method would require.[17][20].

• - 3D printing of constructions offers a wide range of shapes, not like traditional industrial machinery that is limited to manufacturing a short range of shapes.[17].

• - Assembly is unnecessary because the 3D printer is capable of manufacturing and attaching the same parts of a product at the same time.[17].

• - Unlimited design possibilities, since there are no obstacles in the product manufacturing process related to the tool as in other disciplines (for example, ceramics and traditional sculpture).[17].

• - Facilitates the reconstruction of monumental buildings that have been destroyed through the 3D digital replica of a building that subsequently allows its reconstruction.[23].

• - Minimal need for qualified personnel, because the printer works automatically using the guidelines of a modeling file.[17].

• - Possibility of reproducing exact replicas: by scanning a specific object, the printer is capable of reproducing an object identical to the one analyzed.[17].

• - Speed: a home takes about ten days to be built.[23].

• - Possibility of building faster than traditional methods, reducing total operating costs by up to 30% and reducing CO₂ emissions by up to 80%, thanks to its on-site automated factory concept..[24].