PLANTS, APPARATUS,
PLANTS, APPARATUS, COMPONENTS 3D printing of fluoropolymers allows more design freedom PTFE components off the printer 3M has developed a technology to print fully fluorinated polymers in 3D, which is particularly exciting with PTFE applications. Complex structures can be fabricated in one step in this way. In the past, they had to be processed by traditional moulding and assembling the component parts. 3M has selected stereolithography as the additive manufacturing process method for PTFE and other fully fluorinated polymers. The printed parts show similar physical properties to those produced using traditional processing techniques. PTFE is widely used in plant construction. Owing to its chemical inactivity it is well suited for linings, seals and bearings which come into contact with aggressive chemicals. 3M Dyneon Fluoropolymers provide corrosion resistance in chemically and thermally aggressive conditions. They are virtually non-inflammable and have good electrical insulation characteristics. Owing to their high molecular weight and high melt viscosity, it has not been possible in the past to manufacture components such as sliding bearings or PTFE and modified PTFE gaskets from the melt as is the case with other thermoplastics; instead, various pressing and sintering techniques have been employed. The loose powder cover is compacted at a specific pressure during the pressing process. The pressed and compacted material then undergoes a defined sintering cycle. When the crystallisation melting point is exceeded, the PTFE changes to the amorphous state and the powder particles which were compacted previously are sintered together in a homogeneous form. Author Daniela Held Editor, cpp chemical plants & processes With 3D printing technology also complex structures can be produced Complex structures to be generated 3M has now developed a patent-pending technology to print fully fluorinated polymers in 3D. Complex structures, which are otherwise impossible to manufacture or can only be manufactured with expensive traditional processing techniques, can in future be fa - bricated in this way. This flexible new technology paves the way for the production of polymer structures in a single processing step rather than moulding and assembling component parts. Stereolithography is process of choice 3M selected stereolithography, also known as vat polymerisation, as the additive manufacturing process for PTFE and other fully fluorinated polymers. The printed parts exhibit similar physical properties to those produced using traditional processing techniques. Stereolithography involves curing or solidifying a photosensitive material using an irradiation light source. Typical tailor-made formulations for 3D printing of fully fluorinated polymers using stereolithography contain a 46 cpp 1-2017
ASK THE EXPERT 3M combines PTFE knowledge and 3D printing cpp: Mrs. Johnson-Mason, what led to the invention of 3D printing fluoropolymers? Johnson-Mason: 3D printing has become a well-known and respected technology for the manufacturing of products, particularly for prototypes and complex parts. But to date, efforts to apply this technique to fluoro polymers has been a technical challenge. So naturally we looked for ways to apply our materials expertise in that space. cpp: What advantages does this technology offer? Paula Johnson- Mason, Global Director Fluoropolymers, 3M recently at the K Fair involves 3D printing of PTFE via stereolithography, and included the development of a PTFE formulation which could be used with that technique. Every child is one of a kind and unique. Each child needs individual support according to their needs. Please help us by donating. Thank you! Johnson-Mason: 3D printing is particularly useful for producing prototypes or for lowvolume production lots, as the manufacturer does not have to invest in an expensive mold. Additionally, one can produce very complex parts with 3D printing that would otherwise not be able to be produced via injection moulding or machining. One advantage particular to 3D printing of PTFE is material savings. Suspension PTFE is not a melt processable material, so the current method of making a part of S-PTFE is to produce a semi-finished shape (rod stock or blocks) and machine it to the final part, resulting in a significant material waste. cpp: What steps were necessary to make PTFE processable in this form? Johnson-Mason: We have investigated many techniques for 3D printing of fluoro - polymers. The technology we debuted cpp: Is it possible that all Dyneon fluoro - polymers could be processable by 3D printing in the future? Johnson-Mason: We are currently exploring and developing various technologies with multiple fluoropolymers. cpp: Which components could be produced by means of 3D printing? Johnson-Mason: The size of the part is limited only by the size of the vat of the printer, and the technology is particularly useful for complex or intricate shapes that could not be produced by other methods. cpp: In what form is the starting material for 3D printing available? Johnson-Mason: We are still evaluating how 3M will go to market in this space. binder and optional additives as well as the fully fluorinated polymers. The three processing steps required here are aqua gel formation, drying and removal of the binder during heat treatment. This method can also be used for PTFE compounds. It allows 3D printing of spare parts or customised designs with a complex geometry on demand without having to resort to expensive traditional processing techniques. Thanks to the potential material saving and reduced waste, the new technology is also a more sustainable production alternative. Traditional processes for manufacturing parts from PTFE generate substantial quantities of waste. This is reduced to a minimum with 3D printing, however, and any unused material can be reused for the next print job. » www.cpp-net.com Online search: cpp0117dyneon Tel.: 0800/50 30 300 (free of charge) IBAN DE22 4306 0967 2222 2000 00 BIC GENO DE M1 GLS www.sos-kinderdoerfer.de 2016/1 cpp 1-2017 47
