Additive manufacturing, Rapid Prototyping, FDM, Project RepRap,

Michał OLEJARCZYK

Department of Laser Technologies, Automatisation and Organization of Production Wroclaw University of Technology ul. Łukasiewicza 5, 50-371 Wrocław, Poland

Additive manufacturing- factory on your own desk

Additive technologies are new manufacturing technologies which began in 80s last century and they are still developing nowadays. Together with machining and shaping methods they are the group of technologies which give the possibilities to create real object basing on properly prepared numerical model. These aim of these workshops is to show manufacturing possibilities which are in presented technologies and present the process step by step: from numerical model to real object 1. Additive technologies Generative technologies also called additive technologies starts at 80s in XX century. Despite the fact that first generative process was invented about 30 years ago (stereolitography, 1986, Charles Hull), it is now visible how omnipresent it is in appliances such like medicine, aerospace, architecture or design. The common feature of all additive technologies is fact, that material is added layer by layer to just made fragment of built object. Layers are received by dividing properly positioned 3D CAD model using normal surface. These layers are connected with the object using couple of physically-chemical phenomenon fe. using bonding, fotopolimerisation, solidification after laser melting. Material can be provided as a powder, liquid, dense paste or foil, which are used to build obt object where layer in the place is still on the top. Only additive processes give the possibilities to made objects of very complicated shapes, fe. to build object with closed spaces inside or with inside curved canals. First additive technologies were used to build prototypes. Since then in many sources there is used statement „rapid prototyping” what contains all generative technologies. It is obvious that prototyping is still the biggest area of using these technologies. Classification of additive technologies (divided on processes and materials) are showed on figure 1. [1,2,3]. 1.1. FDM Technology Fused deposition modeling (FDM) is one of additive technologies used in manufacturing prototypes, models and other elements. It is developed and commercialized by company Stratasys Inc. in 80s and 90s. Originator of this method is S. Scott Crump (U.S. Patent 5,121,329, 9 June, 1992). The base for printing is file *.stl (StereoLithographics or Stereolithography Language) enabling conversion of CAD model on machine code (G-code). Method of deposition of melted material consists on putting plastic layer by layer

discrete

droplet spray(BPM)

continuous

layer modelling by stamping (FDM)

point by point

surface by surface

holograhic hardening (HIS)

Rapid PrototypingTechnika 3D (przestrzenna)

mikrometalurgy (SLM) stereolitography (SL)

discrete

powder sintering(SLS) layer sprayings (3DP) melting using electrons (EBM)

point by point

layr by lyer using stamping(FDM) continuous

2D Technic (layer)

layer hardening(SGC)

layer by layer

layr spraying (3DP)

layer foil bonding(LOM)

layer clumping (SAHP)

Rys. 1 Metody wytwarzania w technikach RP na podstawie grafu z [3]

The head which is the biggest subassembly is heating material making it semi-liquid just above melting temperature. Controlled 3 axis kinematic system allows to deposition material in specific place. The first layer is deposited on the special plate/platform. After doing the task in one work plane there is translation of 1 layer thickness in normal direction. The next layer is deposited directly on the layer before, when it is cooling down it permanently joins with previous layer. Repeating this cycle in the effect gives us complete model (Fig 2). To provide stability of process there is used preheated platform to reduce contraction of material and increase its adhesion. Sometimes there is used supporting material to get hanging construction and leveling basis of printing. The model and supporting material is applied sequentially by head. After printing supporting material is removed mechanically (BASS) or chemically (WaterWorks). Models obtained by this technic can be made of ABS (about 90% of all), ABSi, policarbons PC, polyphenysulfone, PPSU, PC-ABS, PC-ISO, PLA ,elastomer and wax. Presented version of printer RepRap do not have this possibility. Simmiliar to FDM is Melted and Extruded Modeling (MEM). MEM technology is invented and developed on Tsinghua University in Pekinie nad since 1996 is is like a trade name in Beijing TierTime Technology Co. Ltd. In open source printers like a RepRap is used Fused Filament Fabrication (FFF) technology which is the same in rules and only want to eliminate patent name of FDM. [4].

Rys. 2 Schemat funkcjonalny technologii FDM [5]

1.2. REPRAP Printer Development and dissemination of additive technologies allowed making conception of low-budget printers for personal use . One of first initiatives was RepRap Project (Replicating Rapid-prototyper) working in FFF technology, started in 2004 at Bath University by Adrian Bowyer. The idea of RepRap cam from the need of having wide-spread and simple in use printer which can generate 3D form. On Open license (GNU General Public License) arised a project of 3D printer which do not only create real models but also in its base assumption has a possibility to replicate itself. Moreover using additive technologies is generally very expensive due to the fact of high cost of materials, machines and its worktime. That’s why originator of RepRap Project wanted to build as cheap printer as it is possible. Taking into account economical aspect dr Bowyer made a machine which consists of very simple, standard and easily accessible components. That’s why this project is very popular in the whole world. 1. 3. Low cost 3D printers The increase of popularity of RepRap Project (and in the effect increase of interest of generative methods) contributed to making low-budget 3D printers for hobbyists, low project or plastic offices. The rule is quite the same as is used in professional printers working in FDM technology. The common feature of these models is method of three-dimensional printing based on FDM technology, low cost of buying ( lower than 2500 Euro) and exploitation (but there is a big amount of machines working in stereolitography or 3D printing). Difference is the size of working area, accuracy of printing and program. Describing the low-cost printers there is possibility to divide it into 3 categories. First one is low cost printers based on open architecture, which allow modification of construction and materials ( RepRap, Mendel, Ulimaker3D Printer, Orca v 0,43) Second category consists of devices which have defined construction without possibility of modification (Solidoodle 3rd, MakerBot Replicator™2 or UP! Plus). The last one are professional printers offered by head companies from area of building Rapid Prototyping Devices (Stratasys, 3Dsystems) in ”desk” version fe. µPrint, Mojo, ProJet™ 1000 Personal 3D Printer, which have to fill this area between professional printers for commercial use and devices like RepRap. It is worth to say that every day low-budget printers are more and more precise, cheaper, low failure and more functional from perspective of user. In Table 2 there are basic features of the most popular low- budget printers in comparison to Mendel

2. Decription of measurement place Tab 1. Specification of PRUSA i3 Features Build method Workplace [XYZ]

describe FFF 200 x 250 x 330 mm

Layer thickness

0,1 mm

Building Speed

370 mm3/min

Engines Printed parts

5

Supports

28 Arduino MEGA (ATmel ATmega 2560) none

Material

ABS, PLA

Elekctronics

i.

.

nozzl e

head

frame guides

X axis Z axis

Preheated table

ends engine

Y axis Rys. 3 PRUSA i3

Literature [1] Chlebus E.; Techniki komputerowe CAx w inżynierii produkcji; WNT, Warszawa 2000. [2] Chlebus E.; Innowacyjne Technologie Rapid Prototyping- Rapid Tooling w Rozwoju Produktu; Oficyna Wydawnicza Politechniki Wrocławskiej; Wrocław 2003 [3] Miecielica M.; Techniki Szybkiego Prototypowania- Rapid Prototyping; PW IPiB; Warszawa 2007. [4] Todd, Grimm. FUSED DEPOSITION MODELLING: A TECHNOLOGY EVALUATION. 11/2, www.timecompression.com: Time-Compression Technologies Europe, 2003, s.3. [5] Additive Fabrication; [online: sierpień 2013]; < http://www.custompartnet.com/wu/additive-fabrication>

Notatki

Tab. 2 Examples of low cost printers

Mendel

Solidoodle rd

MakerBot

RapMan

Ultimaker

UP! 3D Printe

Orca

Replicator™2

RapMan 3.2 3D Printer

Ultimaker 3D Printer

UP! Plus

v 0.43

Mendel M4

Solidoodle 3

5th Generation Electronics

Printrun/Pronterface

MakerWare™ Bundle 1.0.2

BFB Axon 2 software

Cura

UP software

Skeinforge

FFF*

FFF

FFF

FFF

FFF

FFF

FFF

2900

2600

7000

5000

8200

5000

4700

DIY***

zamknięta konstrukcja

zamknięta konstrukcja

DIY

DIY

zamknięta konstrukcja

DIY

Size [mm]

500×400×360

355×355×345

490×420×380

600 ×400×180

340×355×390

245x260x350

280×380×290

Workplace [mm]

200×200×140

205×205×2005

285×153×155

270×205×210

210×210×220

140×140×135

250×220×190

Model

Real view

Software Technology Price [PLN]** 1PLN=0,23EUR Type

Materiał Process features webside

PLA, HDPE, ABS ø 3 mm

ABS/PLA ø 1,75 mm

PLA ø 1,75 mm

ABS/PLA

PLA/ABS

ABS/PLA ø 1,75 mm

PLA/ABS ø 1,75 mm

Layer thickness 0,3 mm

In XY axis to0,01 mm, Layer thickness