B. VALENTAN et al.: PROCESSING POLY(ETHER ETHERKETONE) ON A 3D PRINTER ... PROCESSING POLY(ETHER ETHERKETONE) ON A 3D PRINTER FOR THERMOPLASTIC MODELLING OBDELAVA POLYETHER ETHERKETONEA NA 3D-TISKALNIKU ZA TERMOPLASTI^NO MODELIRANJE Bogdan Valentan 1 , @iga Kadivnik 2 , Toma` Brajlih 2 , Andy Anderson 3 , Igor Drstven{ek 1,2 1 Ortotip, d. o. o., Ulica [kofa Maksimiljana Dr`e~nika 6, 2000 Maribor, Slovenia 2 University of Maribor, Faculty of Mechanical Engineering, Smetanova ulica 17, 2000 Maribor, Slovenia 3 Invibio Ltd.,Technology Centre-Hillhouse International, Thornton Cleveleys, Lancashire FY5 4QD, United Kingdom valentan@gmail.com Prejem rokopisa – received: 2012-10-12; sprejem za objavo – accepted for publication: 2013-03-25 PEEK, poly(ether etherketone), is one of the high-quality industrial polymers. It is widely used in extremely demanding areas like automotive, aircraft and space industries. Because of the fact that it is bio-compatible, PEEK is also used for medical implants that are usually made by milling a block of the material. The article presents the results of an investigation of processing PEEK on a 3D printer for thermoplastic modelling. The used procedure is one of the additive manufacturing procedures and, as such, it builds a product by adding material layer by layer to get the finished product. Commercially available machines are unable to achieve the required melting and environment temperatures, so a new machine was developed. The machine was designed and built at the company Ortotip d.o.o. and it is able to produce the parts of up to 130 mm × 130 mm × 150 mm. After the initial testing, test specimens, according to standards EN ISO 527-2: 2012 and EN ISO 178: 2011, were produced and tested at the facilities of the PEEK manufacturer Invibio (from the UK). The article presents the steps taken when developing the PEEK modelling machine, the test methods to verify the mechanical properties of manufactured products and the results of the material testing. The machine was developed to produce medical implants (specific maxillofacial prosthesis), but with additional testing (that will help to improve the mechanical properties of produced parts) practically all bone-replacement implants can be made. Keywords: PEEK, 3D printer, implant, medical application, thermoplastic, FDM, biocompatible, additive technology PEEK, polyether etherketon, je eden izmed visoko kvalitetnih industrijskih polimerov. Uporablja se na zahtevnih podro~jih, kot so avtomobilska, letalska in vesoljska industrija. Zaradi dejstva, da je biokompatibilen, je uporaben tudi za medicinske vsadke, ki so navadno narejeni s frezanjem iz bloka materiala. ^lanek predstavlja izsledke raziskave oblikovanja PEEK s 3D-tiskalnikom za termoplasti~no modeliranje. Uporabljen postopek spada med tako imenovane dodajalne tehnologije in kot tak gradi izdelek po slojih. Komercialno dostopni stroji ne zmorejo dose~i zahtevanih procesnih in okoljskih temperatur, zato je bila razvita nova naprava. Ta je bila oblikovana in izdelana v podjetju Ortotip, d. o. o., in je primerna za izdelke do velikosti 130 mm × 130 mm × 150 mm. Po uvodnih preizkusih so bile izdelane preizkusne epruvete v skladu s standardoma EN ISO 527-2: 2012 in EN ISO 178: 2011 in preizku{ene od proizvajalca PEEK-materiala Invibio (iz VB). Predstavljeni so klju~ni koraki pri razvoju naprave za direktno izdelavo modelov, preizkusne metode za verifikacijo mehanskih lastnosti izdelanih kosov in rezultati meritev. Naprava je bila razvita za izdelavo medicinskih vsadkov (posebno lobanjske vsadke), vendar bo ob dodatnih preizkusih (za izbolj{anje mehanskih lastnosti izdelanih kosov) primerna za vse vrste medicinskih vsadkov. Klju~ne besede: PEEK, 3D-tiskalnik, vsadek, medicinska aplikacija, termoplast, FDM, biokompatibilnost, dodajalne tehnologije 1 INTRODUCTION Today the majority of long-lasting human-body implants are made from three materials. The first is the bone cement, to technicians more known as poly(methyl methacrylate) – PMMA. Its great advantage is that it can be processed during the operation since it can be made of two components (liquid and powder) that are mixed together and directly processed (by hand or with some basic tools) in a short time (the curing time can be as short as 2 min). The production of the implants made from solid PMMA is used only in special cases like the lens for trabeculum. The second material is titanium (actually one of the titanium alloys) that is processed with a conventional machining process (usually the CNC milling or turning) or with one of the additive manu- facturing procedures like SLM (selective laser melting), 1 MLSS (metal-laser-sintering system) 2 or EBM (elec- tron-beam melting). 3 After a long-term use titanium shows some problems, 4 but it is irreplaceable when excellent mechanical properties are needed. The material that promises the most is PEEK – poly(ether etherketo- ne). The implants from PEEK 5–7 are usually made with the conventional machining process or the method, pre- sented in 2010, of direct manufacturing with an SLS (selective laser sintering) machine. 8 Since PEEK is ther- moplastic it can be formed also with the other proce- dures that are widely used for other thermoplastics. 9 The challenges are the specific requirements relating to a higher viscosity (Figure 1) that need to be taken into consideration, so the idea of developing a dedicated device (a 3D printer for thermoplastic modelling) was born. 2 BASIC PRINCIPLES OF THE 3D PRINTER FOR THERMOPLASTIC MODELLING The 3D printer for thermoplastic modelling is basi- cally an FDM (fused-deposition modelling) machine. As Materiali in tehnologije / Materials and technology 47 (2013) 6, 715–721 715 UDK 621.7:004.89 ISSN 1580-2949 Original scientific article/Izvirni znanstveni ~lanek MTAEC9, 47(6)715(2013)