Oct. 27, 2014 | By Alec
Observant readers may have noticed that 3D printing technology has slowly been invading the world of fashion. Just in the past two months or so, we've already seen various 3D printed clothes and accessories emerge on the world's most fashionable runways. Remember these 3D printed pieces at the New York Fashion Week in September, or Chromat's daring creations a few weeks ago?
Sure, these are clothes. But it's not quite fair to call these objects textiles as well. For textiles, following millennia-old production methods, consists of lots and lots of strands covering each other to form cloth. In contrast, most of the pieces of fashion we have seen in recent months consist of solid layering, rather than separate strands pressed together.
But we can hear you thinking: but surely layer-by-layer production isn't that different from strand-over-strand extrusion? Well, theoretically it isn't, but it just remains to be seen if it's practically possible. That's what makes a recent project by German scientists from the Faculty of Textile and Clothing Technology at the Niederrhein University of Applied Sciences so interesting.
A team of scientists consisting of R. Melnikova, A. Ehrmann and K. Finsterbusch sought to artificially recreate textile structures using 3D printing technology. And as different 3D printing technologies and filaments come with different advantages and disadvantages, they even tried several approaches.
All designs, however, used very accessible technologies: the free 3D graphics software Blender was used in the designing phase while tried-and-trusted Netfabb was used to check and repair these before printing. The FDM 3D printer X400 from German RepRap was used for all FDM-based experiments, while the scientists turned to Shapeways services for their SLS trials.
As they explained, 'printing of textile-like patterns is still rare. […] In design, garments such as bikinis, complete dresses, or shoes are 3D printed. These garments, however, are clearly produced for show, not for everyday wearing. Thus, the project described here concentrates on more textile-like patterns which can be combined with traditional textiles or even replace them.'
Overall, they sought to test three different textile structures: weft-knitted structures, as wool would be used for, layered structures and lace patterns. Results were achieved using a number of different materials. The FDM 3D printer relied on PLA and soft PLA (a mixture of PLA and softener). The SLS 3D printer, meanwhile, printed in a nylon material called 'White strong & flexible'.
However, the team from Niederrhein University also relied on some very interesting materials from German inventor and filament wizard extraordinaire Kai Parthy. He is the man behind such interesting and multipurpose filaments as the PORO-LAY line, that consists of a number of sturdy, but flexible and even absorbent filaments. For this experiment, the German scientists also used BENDLAY filament (harder than PLA but not as brittle as ABS) and LAYFELT, that is very sturdy but can be easily softened by immersing it in water. Incidentally, LAYFELT will be made available through Kai's ebay shop and several online dealers in the coming days.
3D printing layered structures
This resulted in some very intriguing textile-like structures. Unsurprisingly, the FDM 3D printer was perfectly capable of reproducing layered cloth patterns with PLA material, as that is what FDM technology is all about. The image above shows a test structure, used to examine whether single strings can be deposited on top of relatively open structures without any support structures. This resulted in a FDM print which was largely similar to the test structure (below).
However, there is a downside: fragility. The strings may sometimes break, even if a minimum diameter of 0.4 mm is maintained. While this is a problem that might be remedied with more futuristic filaments, the limitations of this experiment meant the scientists did not pursue it any further.
3D printing lace patterns
More interesting was the production of lace patterns with a 3D printer, for which Kai's filaments proved very useful indeed. These lace-like structures have been created that start with a partly open base layer, but unlike the previous test, do not include any free-floating areas.
Lace pattern printed in LAYFELT(LayTekkks) material
The lace patterns have been inspired by the well-known Plauen lace, which contain mostly floral and round elements on a base layer connecting these parts. Due to the absence of free-floating areas, printing by the FDM process is unproblematic, if all connection lines have large enough diameters.
As can be seen in the pictures, the extremely flexible nature of LAYFELT made it perfect for this type of cloth. It is transported to the nozzle without the transport problems that soft filaments may generate in several FDM 3D printers. After finishing the printing process, however, it can be put into warm water for a period of minutes to hours, leading to the hard part of the material being dissolved and thus softening the resulting sample more and more, the longer it is immersed in water.
3D printing weft knitted structures
However, most fascinating were their attempts at printing weft-knitted structures, which could closely resemble actually wearable clothes. As can be seen in the pictures below, the results were mixed. The weft-knitted structures have been based on a CAD model made with Blender and Adobe Illustrator. The results reveal a material thickness, as well as a distance between neighboring stitches, that are large enough for the SLS or the FDM technology, respectively. The printability of the design has been verified using Netfabb.
A CAD model of a single face weft knitted fabric made with Blender
The SLS 3D printer worked with a material thickness of 0.8 mm and a minimum distance between the different stitches of 0.4 mm. The resulting model reproduces in principle the look of a single face weft knitted fabric; however, it should be mentioned that the lack of flexibility of the material itself leads to distinctly different mechanical properties of the model, compared with knitted structures created from traditional textile yarns.
SLS technology was thus perfectly capable of recreating textile weft-knitted structures, but these are obviously not very flexible and therefore not suitable to wear. And there's the additional practical problem of all SLS printers: everything is of the same material, meaning that 'multi-material models have to be printed separately and joined afterwards.'
SLS printed results
FDM technology proved to be similarly unsuitable for the time being. The FDM 3D printer principally needed to work with support structures to create the weft-knitted effect in Bendlay filament. A different or the same material as used for the model itself could be used for support, and is absolutely necessary to realize the short distances between the stitches. However, the scientists had some difficulty to realize the support material on such a small scale. Additionally, the design had to be magnified to reach the minimum material thickness (here 1.88 mm) necessary to avoid breakage of the structures.
Nevertheless, the support structures were still too fine to be produced by the printer as desired; instead undesirable clots were created which partly destroyed the model. In this way, it is not possible to build such a relatively fine model by FDM.
FDM BENDLAY results with support structure.
However, soft PLA was more promising, and did not even require support structures to be 3D printed. Unexpectedly, this experiment led to significantly better results. While there were still fine undesirable connections between the stitches, following the trace of the printing nozzle which sometimes extrudes material when this process is stopped, the basic structure is clearly visible.
FDM soft PLA results, without support structures
The stitches are also mostly separated, and the flexibility of the material itself is almost comparable to that of a textile knitted structure. Nevertheless, it should be mentioned that the surface of the soft PLA model still exhibits roughness on a macroscopic scale, contrary to the microscopic roughness of man-made or natural textile fibers.
While in no way ideal, could such flexible materials hold the key to printing actual textiles in the future? The German team behind these interesting experiments believe so. To be sure, 'ABS has turned out to be often too brittle for the desired fine structures, and hard PLA, as well as the nylon used in SLS printing, can be too hard to be used in typical textile applications.'
But other filaments, like soft PLA – especially in combination with sturdier and more durable materials like BENDLAY – has proven to be able to reproduce some textile-based structures: 'These materials enable the development of novel patterns and construction methods for clothing and related areas, allowing for new designs as well as new functionalities that cannot be achieved by conventional textile fabrics.'
Furthermore, the German scientists behind this project also briefly looked into additional multi-material models. After all, no piece of clothing consists of a single material; even if it's just a single piece of fabric, eyelets, buttons and reinforcement mixes are generally included. As it happens, FDM 3D printers with two or more nozzles are already available, and theoretically offer to print these additional components.
A brief experiment of this nature was also done. The figure below shows the construction of a three-layer base. Planned to be printed with soft PLA, it also includes a harder ring (depicted red) which fits in the gap of the soft middle layer to offer support. Using this type of technology, it is thus indeed possible to create multi-material textiles with 3D printing technology. Similarly, lace models with three or more layers of soft PLA can also be created, which contain reinforced parts constructed from hard PLA or BendLay.
Of course, this is still an experiment and has so far proven to be incapable of producing results that are as dense and sturdy as wearable textiles should be. However, this excellent and promising study does suggest that even regular RepRap FDM are theoretically capable of recreating traditional weaving methods when the right filament is used. How long would it take before we can see a 3D printed woollen scarf on the runway?
You can find this paper, entitled '3D printing of textile-based structures by Fused Deposition Modelling (FDM) with different polymer materials', here.
Posted in 3D Printing Materials
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alvaro wrote at 10/28/2014 5:28:53 PM:
We can use it to build scaffolds for regenerative therapy.
Noah Hornberger wrote at 10/27/2014 7:16:55 PM:
Just wondering why the FDM printer is using PLA and not Nylon, given nylon's superior flexing properties and overall stability? Taulman nylon extrudes from about 225-250 C.