The Additive Manufacturing (AM) is comprising many technologies that have become important and strategical for production in the last years. The 3D printing is one of them and is showing many advantages against the others in order to supplant their market. Desktop Metal is an American company, one of the very first industry able to put on the market a machine that offers Bound Metal Deposition technology and spread it worldwide. The aim of this work is to provide a preliminary characterization of Bound Metal Deposition (BMD) process, also known as Fused Filament Fabrication or Metal Free Forming (FFF and MFF), via a unique extrusion-based machine commercialized as Desktop Metal Studio System. The BMDTM is still not known in literature, this thesis tries to investigate the characteristic of 17-4 PH stating from feedstock at green state and following the production chain until a real solid component is realized. Tensile testing analysis on dog-bone specimens were done on multiple geometries dog-bone specimens. Since everything was proprietary of Desktop Metal nothing was left behind, it was put under test mechanical resistance as well as relative density and internal composition of feedstock. Furthermore, the role of internal blemishes was fundamental to understand how the printing parameters are influencing the process, for this reason two further experimentations were considered to study the internal defects and the behaviour of material. Internal porosity and thermal shrinkage were analysed by means of Archimede’s method and via direct measurements on cubic specimens with Mitutoyo Quick Vision Pro system. The work is ended with an industrial application case born from a collaboration between DTU institution and Politecnico di Milano. Preliminary studies were carried out on superficial topography characterization for several samples, operations that added precious value and information on the printing ability of the Bound Metal Deposition.
La Manifattura Additiva (AM) comprende molte tecnologie diventate importati e strategiche per la produzione negli ultimi anni. La stampa tridimensionale è una di queste tecnologie la quale mostra molti vantaggi nei confronti delle altre, tanto da soppiantarne una parte di mercato. Desktop Metal è una compagnia americana, una delle prime capace di mettere sul mercato una macchina con tecnologia adatta alla deposizione tridimensionale di metalli, diffusa ormai nel mondo. Lo scopo di questa tesi è quindi quello di caratterizzare il processo di stampa tridimensionale per estrusione (BMD), altresì definito come modellazione a deposizione fusa (FFF) o formazione libera di metallo (MFF), attraverso una stampante unica nel suo genere e commercializzata come Desktop Metal Studio System. La BMD non è ancora trattata in letteratura, questa tesi prova quindi ad investigare le caratteristiche di componenti in 17-4 PH partendo dallo stato al verde e seguendo la catena produttiva fino alla realizzazione di un componente in metallo pieno. Prove di trazione su provini ad osso-di-cane standardizzati sono state eseguite su molteplici geometrie. Considerando che tutto è stato brevettato da Desktop Metal nulla è stato lasciato al caso, si è testata la resistenza meccanica come anche la densità relativa e la composizione interna della materia prima al verde. Inoltre, il ruolo dei difetti interni è di fondamentale importanza per capire come i parametri di processo influenzano lo stesso, per questa ragione si sono considerate due sperimentazioni aggiuntive, per meglio comprendere il comportamento del materiale.La porosità interna e l’effetto del ritiro termico sono state quindi analizzate, rispettivamente con metodo di Archimede e con misurazioni dirette su provini cubici attraverso Mitutoyo Quick Vision Pro. Il lavoro si conclude con un caso applicativo nato da una collaborazione tra DTU e Politecnico di Milano. Studi preliminari sono stati condotti sulla caratterizzazione topografica della superficie di svariati campioni, operazione che ha aggiunto valore ed informazioni utili riguardo le abilità di stampa della Bound Metal Deposition.
Investigation of mechanical and geometrical properties of 17-4PH additive parts manufactured via bound metal deposition
CHIESI, MIRCO
2019/2020
Abstract
The Additive Manufacturing (AM) is comprising many technologies that have become important and strategical for production in the last years. The 3D printing is one of them and is showing many advantages against the others in order to supplant their market. Desktop Metal is an American company, one of the very first industry able to put on the market a machine that offers Bound Metal Deposition technology and spread it worldwide. The aim of this work is to provide a preliminary characterization of Bound Metal Deposition (BMD) process, also known as Fused Filament Fabrication or Metal Free Forming (FFF and MFF), via a unique extrusion-based machine commercialized as Desktop Metal Studio System. The BMDTM is still not known in literature, this thesis tries to investigate the characteristic of 17-4 PH stating from feedstock at green state and following the production chain until a real solid component is realized. Tensile testing analysis on dog-bone specimens were done on multiple geometries dog-bone specimens. Since everything was proprietary of Desktop Metal nothing was left behind, it was put under test mechanical resistance as well as relative density and internal composition of feedstock. Furthermore, the role of internal blemishes was fundamental to understand how the printing parameters are influencing the process, for this reason two further experimentations were considered to study the internal defects and the behaviour of material. Internal porosity and thermal shrinkage were analysed by means of Archimede’s method and via direct measurements on cubic specimens with Mitutoyo Quick Vision Pro system. The work is ended with an industrial application case born from a collaboration between DTU institution and Politecnico di Milano. Preliminary studies were carried out on superficial topography characterization for several samples, operations that added precious value and information on the printing ability of the Bound Metal Deposition.| File | Dimensione | Formato | |
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https://hdl.handle.net/10589/170059