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Alberto Garofalo
7 anni fa
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1 Fused deposition Modelling

2 + Question #1 14/10/2015

3 + Question #2 14/10/2015 Indicates which of the following material has the lower working temperature (for FDM technology)

4 + Question #3 14/10/2015 Indicate the working temperature of ABS (FDM technology) T > 300 T <= <T<= <T<= <T<= <T<=150

5 + Fused deposition modelling (FDM) FDM is the second most widely used rapid prototyping technology, after stereolithography. A plastic filament is unwound from a coil and supplies material to an extrusion nozzle. The nozzle is heated to melt the plastic and has a mechanism which allows the flow of the melted plastic to be turned on and off. The nozzle is mounted to a mechanical stage which can be moved in both horizontal and vertical directions. As the nozzle is moved over the table in the required geometry, it deposits a thin bead of extruded plastic to form each layer. The plastic hardens immediately after being squirted from the nozzle and bonds to the layer below. The entire system is contained within a chamber which is held at a temperature just below the melting point of the plastic.

6 + Fused deposition modelling

7 The Rep Rap Project OPEN 3D PRINTING

RepRap takes the form of a free desktop 3D printer capable of printing plastic objects.

8 + Open 3D printing: the RepRap project RepRap is first general-purpose self-replicating manufacturing machine. RepRap takes the form of a free desktop 3D printer capable of printing plastic objects. Since many parts of RepRap are made from plastic and RepRap prints those parts, RepRap selfreplicates by making a kit of itself - a kit that anyone can assemble given time and materials.

9 + The RepRap Project

10 + The RepRap Project

11 + The RepRap Project

12 + The RepRap Project

13 + How many RepRaps?

14 With basics of polymer rheology MATERIALS FOR FDM

15 + Materials FFF = Fused Filament Fabrication Filament: fine diameter plastic that exits from an extruder (some may refer to the plastic feed stock as filament as well) Typically, the diameter of the filament varies between 1 mm and 3mm The standard extruder produces filament using high pressure and heat to force molten plastic thru a very tiny hole.

16 + Materials Standard materials: Poly-Lactic-Acid (PLA) (soft and hard) Acrylonitril-Butadiene-Stiren (ABS) Experimental materials: Nylon Polycarbonate (PC) Poly vinyl alcohol (PVA) Conductive (carbon and graphen loaded materials) Metallic loaded plastics

17 + Rheology

18 + Variabili che influenzano la reologia dei polimeri Variabili reologiche: deformazione velocita di deformazione Variabili strutturali-compositive: peso molecolare medio polidispersita (Mw/Mn) architettura molecolare (es: presenza di ramificazioni) presenza di una fase dispersa (quantita, dimensionale media e distribuzione, forma) contenuto di additivi (es: plastificanti) Variabili termodinamiche: pressione temperatura

19 + Curva di flusso (viscosita in regime stazionario): comportamento shear thinning comportamento shear thinning Viscosità (Pa s) zona newtoniana dati capillare dati piatto-cono best fit eq. Cross Polistirene M w = T=200 C zona di power law h 0 = 7.0 l = 0.14 n = 0.79 h equazione di Cross 0 = 1+ ( l g &) ( 0) n bassi De Shear rate (s -1 ) alti De

20 + Viscosita e condizioni tipiche di processo

21 + Effetto del peso molecolare Effetto del peso molecolare Polistirene M w = h 0 = Pa s Viscosità (Pa s) Polistirene M w = h 0 =7.000 Pa s T=200 C Shear rate (s -1 ) Una caratteristica distintiva dei polimeri ad alto peso molecolare: h µ M w Seminario di Reologia, Università di Padova, 2008

22 + Effetto della polidispersita

23 + Fenomeni dovuti all elasticita del fuso

24 + Il die swell del polistirene

25 + Altra manifestazione dell elasticita del fuso: la pressione di ingresso

26 + La melt fracture aumenta all aumentare della shear rate

27 + Comportamento reologico di sistemi polimerici multifasici Alcuni tipi di sistemi multifase: polimeri rinforzati con cariche minerali o fibre polimeri tenacizzati con fase gommosa dispersa blend immiscibili copolimeri a blocchi schiume Variabili che influenzano la reologia di sistemi multifase: quantita di fase dispersa media e distribuzione delle dimensioni particelle fattore di forma delle particelle distanza inter-particellare media deformabilita della fase dispersa

28 + Un importante effetto della fase dispersa: lo yield stress

29 + polimeri con fase gommosa (reticolata) dispersa

30 A LOOK INTO SLICING PARAMETERS

31 + Cura

32 + Slic3r

33 + Stratasys Catalyst

34 + Stratasys Catalyst

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Fused Deposition Modelling (FDM)

Fused Deposition Modelling (FDM) Micro e Nano Sistemi carmelo.demaria@centropiaggio.unipi.it Fused deposi7on modelling (FDM) FDM is the second most widely used rapid prototyping technology, a?er stereolithography.