In this thesis is experimented the possibility to use Selective Laser Melting (SLM) to produce tooling components for elastoforming processes, for the production of sheet metal decorative embossing. A first research shows which are the actual products for metallic architectural decoration on the market, and how these are nowadays used for the decoration in interior design projects. At the same time the research focused on the most common production technologies that allow the realization of textured complex shaped molds for decorative embossing. From this first analysis emerged the reasons that brought to study the combination of SLM and elastoforming, outlining technological actual technological limits of cold sheet metal working techniques, which represent a gap between art, fashion and industry. In a second research phase included the design of an elastoforming prototyping mold and seven different textured punches. The embossing metal tiles, based on the Planium Tgroup project called AC02 Stick on, where dimensionally adapted to the prototyping instrumentation. The third phase of this thesis is devided in two steps. A first step for the production of the embossing tools, and a second step for the production, through elastoforming embossing, of the sheet metal tiles. The seven textured punches made out of “Maraging” metal, where produced at the laser laboratory “Sitec - Laboratorio per le Applicazioni Laser” of the Mechanical Department of Politecnico di Milano with a Truprint3000 Machine. The print was performed from the researchers of the lab. Thermal treatments and postproduction machining was subsequently performed, from the specialists of the tooling lab of Terenzi S.r.L – TGroup, who also produced the embossing die for the experimentation. The punching department of Terenzi S.r.L. performed the lasercut of 200 tiles envelops out of copper sheet metal (0,3mm thickness) and 200 tiles out of brass sheet metal ( 0,3mm thickness). Half of the tiles envelops where chemically hatched through galvanization process. The embossing of the tiles was eventually performed, with approximately 50 tiles (25 tiles out of copper and 25 tiles out of Brass) for each of the seven textures. The last part of the experimentation was performed with the aim to quantify the loss of resolution and the transfer fidelity of the process, comparing the ideal texture design with the SLM produced surface and the elastoformed surface. For each texture was acquired the topography of the SLM surface, the embossed brass surface and the embossed copper surface. The scan was performed with an Alicona Deep Focus (focus variation technology) at the metrology lab of Politecnico di Milano. The acquired surfaces where analised following the normative ISO 25178 (Geometric Product Specifications (GPS) – Surface texture: areal) with the software MountainsLa-Digital Surf. The study has shown the relation between the SLM process roughness and distorsions, with the ideal designed motif textures. Morover it was analysed the loss of resolution of the hole process, in terms of motifs quantity and surface dimensional accuracy, compared to the original design.
In questa tesi viene sperimentata la possibilità disfruttare la tecnologia additiva SLM (Selective LaserMelting) per la produzione di attrezzatura (punzoni) dedicata alla goffratura decorativa di lamiere metalliche mediante elastoformatura. Una prima indagine espone quelle che sono le soluzioni per la decorazione metallica attualmente presenti sul mercato, e come queste vengano ad oggi utilizzate nel mondo della decorazione di interni. Sono state ricercate in parallelo le tecnologie produttive più comuni, che ad oggi permettono di ottenere stampi decorativi complessi dedicati alla goffratura e al bassorilievo delle lamiere. Da questa analisi sono state quindi riassunte le motivazioni che hanno spinto ad indagare tali combinazioni di tecnologie produttive, evidenziando i limiti tecnologici dedicati alle lavorazioni delle lamiere metalliche, i quali non favoriscono un’interazione dinamica tra arte, moda e produzione. In una seconda fase progettuale è stato concepito uno stampo prototipale e sette punzoni di goffratura, riportanti sette testure differenti tra di loro. Sono state di conseguenza adattate le misure delle piastrelle goffrate, partendo dal progetto originale AC02 Stick-on di Planium_Tgroup. La terza fase, di carattere sperimentale si è distinta in due step. Un primo per la realizzazione dell’attrezzatura di goffratura ed un secondo step per la realizzazione della produzione pilota di lamiere imbutite. I sette tasselli sono stati prodotti presso il Sitec-Laboratorio per le Applicazioni Laser del dipartimento di meccanica del Politecnico di Milano con una TruPrint 3000, dal personale di ricerca del dipartimento. Successivamente sono stati trattati termicamente e lavorati presso l’attrezzeria di Terenzi S.r.L- TGroup, la quale si è occupata di realizzare lo stampo e il sistema portastampo per la produzione pilota. Presso il reparto tranceria di TGroup sono state tagliate tramite tecnologia laser ca. 175-200 piastrelle in lamiera ricotta di in rame con spessore 0,3mm e altrettante piastrelle sono state prodotte in lamiera di ottone ricotta di pari spessore. La metà delle piastrelle sono state successivamente ossidate tramite processo elettrochimico. Infine è stata eseguita l’imbutitura su tutte le piastrelle, ca. 50 piastrelle (25 di rame e 25 di ottone) per ogni grafica progettata. L’ultimo passaggio è stato eseguito con lo scopo di quantificare la perdita di risoluzione e la fedeltà di trasferimento della grafica originale di progetto sulla lamiera metallica. Per ogni testura di progetto, è stata scansionata la superficie motivale del punzone prodotto in SLM e le corrispettive lamiere goffrate in rame e ottone (una per materiale). L’acquisizione dei dati superficiali è stata eseguita presso il laboratorio di metrologia del dipartimento di meccanica del Politecnico di Milano con una Alicona Deep Focus ( variazione di fuoco). I risultati sono stati successivamente elaborati secondo la normativa ISO 25178 (Geometric Product Specifications (GPS) – Surface texture: areal), tramite il software MountainsLab- Digital Surf. L’analsi di qualifica ha evidenziato la relazione tra la rugosità superficiale tipica del processo SLM e le distorsioni da esso causate, con i motivi testurali della geometria ideale. E’ stato inolte possibile quantificare sommariamente la perdita di risoluzione riscontrata sulle lamiere goffrate, in termini di quantità, dimensione e acutezza delle superfici, a confronto con le superfici dei punzoni di goffratura metallici (SLM) e le superfici ideali.
Elastoformatura e additive manufacturing : una indagine sperimentale su possibilità e limiti dell'elastoformatura con attrezzaggio prodotto mediante tecnologia selective laser melting, per la goffratura decorativa della lamiera
Vezzani, Sergio
2019/2020
Abstract
In this thesis is experimented the possibility to use Selective Laser Melting (SLM) to produce tooling components for elastoforming processes, for the production of sheet metal decorative embossing. A first research shows which are the actual products for metallic architectural decoration on the market, and how these are nowadays used for the decoration in interior design projects. At the same time the research focused on the most common production technologies that allow the realization of textured complex shaped molds for decorative embossing. From this first analysis emerged the reasons that brought to study the combination of SLM and elastoforming, outlining technological actual technological limits of cold sheet metal working techniques, which represent a gap between art, fashion and industry. In a second research phase included the design of an elastoforming prototyping mold and seven different textured punches. The embossing metal tiles, based on the Planium Tgroup project called AC02 Stick on, where dimensionally adapted to the prototyping instrumentation. The third phase of this thesis is devided in two steps. A first step for the production of the embossing tools, and a second step for the production, through elastoforming embossing, of the sheet metal tiles. The seven textured punches made out of “Maraging” metal, where produced at the laser laboratory “Sitec - Laboratorio per le Applicazioni Laser” of the Mechanical Department of Politecnico di Milano with a Truprint3000 Machine. The print was performed from the researchers of the lab. Thermal treatments and postproduction machining was subsequently performed, from the specialists of the tooling lab of Terenzi S.r.L – TGroup, who also produced the embossing die for the experimentation. The punching department of Terenzi S.r.L. performed the lasercut of 200 tiles envelops out of copper sheet metal (0,3mm thickness) and 200 tiles out of brass sheet metal ( 0,3mm thickness). Half of the tiles envelops where chemically hatched through galvanization process. The embossing of the tiles was eventually performed, with approximately 50 tiles (25 tiles out of copper and 25 tiles out of Brass) for each of the seven textures. The last part of the experimentation was performed with the aim to quantify the loss of resolution and the transfer fidelity of the process, comparing the ideal texture design with the SLM produced surface and the elastoformed surface. For each texture was acquired the topography of the SLM surface, the embossed brass surface and the embossed copper surface. The scan was performed with an Alicona Deep Focus (focus variation technology) at the metrology lab of Politecnico di Milano. The acquired surfaces where analised following the normative ISO 25178 (Geometric Product Specifications (GPS) – Surface texture: areal) with the software MountainsLa-Digital Surf. The study has shown the relation between the SLM process roughness and distorsions, with the ideal designed motif textures. Morover it was analysed the loss of resolution of the hole process, in terms of motifs quantity and surface dimensional accuracy, compared to the original design.| File | Dimensione | Formato | |
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https://hdl.handle.net/10589/169629