Direct digital manufacturing of products based on high content of stone powder

Pereira, João Miguel Júnior Loja

http://hdl.handle.net/10400.8/5682

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Authors

Pereira, João Miguel Júnior Loja

Advisor(s)

Mateus, Artur Jorge dos Santos

Abstract(s)

Residue creation from industrial transformation processes are the focus of circular economy studies with the intent to boost revenue and improve environmental impact. As in the case of stone sludges and powders, residue elimination or re-usage, would bring forth reductions in post processing costs, improve environmental impact, as well as adding new revenue streams with added products to the companies portfolio. This project aims to develop a technical road-map of materials and processes for stone residues and powders, in which they are incorporated and transformed into new products, via additive manufacturing, using thermosetting polymeric materials as binder and incorporating them in different mixture rates. Trial and error experimental processes, using Biresin G26, Pavistone 1K and Pavistone 2K resins, incorporating a variety of filler ratios, determine that, usable compounds have filler contents from 30 to 86% wt. Resulting compounds were extruded manually, via syringes, and approved mixtures undergo mechanically assisted extrusions, via an adapted deposition printer. Materials with promising outcomes for additive manufacturing techniques define the material processing windows. Materials in this study were subjected to tensile testing, hardness tests and micro computed tomography scans. Joint analysis of these properties and produced extrusions then define the admissible additive manufacturing technique for industrialization. This study aims to provide results in the domain of material properties and equipment feasibility. Results show that: filler additions lead to a decrement of the mechanical properties; Losses of properties up to 90% were recorded, with exceptions of minimum gains of 170% for specific binder/filler combinations; filler increase drives increases of porosity; and mixtures with growth in their curing processes are not suitable for additive manufacturing processes that require defined form. The wide range of specifications of these materials and their initial formulations, will provide a wide range of end products that can also be applied in a multitude of applications. Existing technology in conjunction with the concept extruding head of this project, provide a system that is adjustable for a wide latitude of materials and end products.