Development of a cement-based extrusion system for application in 3D printing

Abstract

Traditional construction has forged a paradigm in which any object made of concrete is limited to having a square or round shape due to the high cost of the molds used to cast the cementitious material. On the other hand, being an activity with a high degree of manpower required, it is highly dangerous since workers are exposed to hazards such as working at heights, in unstable structures, in confined places, and surrounded by heavy materials and machinery.

Additive manufacturing has been implemented in multiple industries; construction is no exception. Where flexibility in design, speed, and automation are the factors that attract the most attention. However, for its application in a context such as the Mexican, ways must be found to develop materials and equipment that allow simplifying the technique, so that its massification is facilitated.

In a context of confinement due to pandemic, this project explored the components and proportions that constitute a basic mortar to be 3D printed by extrusion. Qualitative methods were developed for the evaluation of mortars and compared with quantitative methods.

The design and manufacture by 3D printing of an extruder were carried out that allows depositing layers of material stably and continuously. In addition, its design allows easy material feeding, easy coupling to a printing robot, and easy assembly and disassembly for cleaning.

Finally, with the mortar and extruder developed, they were incorporated into a printer in which an experimentation process was carried out that led to defining the parameters of movement speed, extrusion speed, and distance from the nozzle.

Some of the main contributions of this thesis, apart from the basic mortar for 3D printing with Mexican materials, and the design of the extruder. were the qualitative evaluation methodologies and the definition of printing parameters. that can be used for future projects to scale the technique.