We present DefeXtiles, a rapid and low-cost technique to produce tulle-like fabrics on unmodified fused deposition modeling (FDM) printers. The under-extrusion of filament is a common cause of print failure, resulting in objects with periodic gap defects. In this work, we demonstrate that these defects can be finely controlled to quickly print thinner, more flexible textiles than previous approaches allow. Our approach allows hierarchical control from micrometer structure to decameter form and is compatible with all common 3D printing materials.

In this work, we introduce the mechanism of DefeXtiles, establish the design space through a set of primitives with de-tailed workflows, and characterize the mechanical properties of DefeXtiles printed with multiple materials and parameters. Finally, we demonstrate the interactive features and new use cases of our approach through a variety of applications, such as fashion design prototyping, interactive objects, aesthetic patterning, and single-print actuators.

DefeXtiles are thinner, more flexible, and faster to fabricate compared to other approaches. Since our approach prints the textiles perpendicular to the print bed, complex geometries can be produced including pleated and curved textiles, as well as metamaterial structures. DefeXtiles are quasi-woven textiles in that they appear similar to a woven textile due to their flexibility, have an apparent warp/weft, and stretch along their bias, but lack the sewability, the bias in both directions, and the softness of woven textiles. These quasi-woven textiles, henceforth referred to as textiles for simplicity, have a look and feel comparable to tulle. With our approach, a standard 3D printer can print decameters of fabric in a single print. The use of multi-material printers further extends the design space of this technique, allowing users to embed circuit traces into the textile via conductive filament.

Under-extrusion is often seen as a defect in fused deposition modeling (FDM) 3D printing, as it can result in a 3D print with gaps. In DefeXtiles, we intentionally exploit this phenomenon to introduce gap defects that afford the prints greater flexibility than a continuous sheet of plastic. By leveraging the periodic deposition and stretching of thermoplastics, we generate textiles in a single nozzle pass.

Altogether, the benefit of this approach is that flexible, thin textiles of many materials can be quickly printed into arbitrary shapes with tunable properties using unmodified, inexpensive 3D printers.

DefeXtiles presents the following contributions:

-A fast and accessible approach to 3D print quasi-woven textiles that are much thinner and more flexible than previous methods and can also be structured in complex three-dimensional forms.

-A study of the relevant printing parameters to control the mechanical and aesthetic properties of the textile.

-The development of workflows to enable surface patterning, warp direction control, multi-material printing, and production of ultra-long textiles.

-Demonstration of applications including sensing textiles, actuators, garment design/augmentation.

-A variety of post-processing techniques can be used on such textiles, such as heat-bonding, sewing, and de-pleating.

Additional Lecture Video here: https://vimeo.com/manage/videos/466316695

For thousands of years, the manufacturing of textiles into shaped forms has remained largely the same — fiber be-comes a fabric which is then constructed into a 3D object. Machine knitting has made a considerable advance in changing this paradigm as the fabric and form can be generated simultaneously. Inverse design pipelines for machine knit-ting have further shifted the nature of textile construction towards the computational production of fully shaped textiles. Despite these advances, the ability to generate complex 3D forms with textiles outside of industrial manufacturing settings remains elusive. The high-tech approach, machine knitting, currently use expensive machines with a significant learning curve for programming. The low-tech approach, classic sewing, requires skilled and practiced hands to carry out pain-staking processes such as draping, tracing patterns onto fabric, adding seam allowances, and sewing.

In this work, we demonstrate that under-extrusion can be leveraged to quickly print thin, flexible, textiles. Specifically, as the extrusion multiplier decreases, there exists an ideal regime where globs form with fine strands connecting them.

As the printing continues, the globs continue to stack on top of each other forming a quasi-warp. In between these globs are fines strands of filament that form the quasi-weft. Hence-forth, we will refer to this process as glob-stretch printing, and the quasi-warp/quasi-weft will be referred to as warp/weft. It is important to note that the extrusion rate is not dynamic: it does not extrude slightly more to form each pillar as it passes. Instead, the globing and stretching simply occurs when too little material is extruded to form a solid wall but enough where there is some periodic interlayer adhesion.

The print warp has a tendency to lean opposite the nozzle direction. If the nozzle prints a sheet from left to right, the pillars will drift to the left. Pillars that drift to the right can be achieved by printing from right to left. Finally, straight columns can be produced by alternating the print direction.

Glob-stretch printing does not just yield textile-like aesthetics and breathability, but also textile-like properties such as flexibility and stretchability even with classically rigid materials such as polylactic acid (PLA). The flexibility is due to the many gaps lowering the moment area of inertia during bending (i.e., less material is being bent) compared to a perfect sheet of the same thickness. The stretchability of DefeXtiles is mostly due to the extremely thin weft which can move freely. Acting as hinges connecting the warp pillars, the weft bends in-plane to accommodate stretching.

A key advantage of our approach is it requires no preparatory steps, no mandatory post-processing, no extra nozzle movements, and no specialized printing hardware. Because of this, our approach allows us to combine the affordances of textiles with nearly all the benefits of well-developed 3D printing workflows. That is, support of a diverse range of materials and forms, hands-free fabrication, rapid production and iteration, full use of the print volume, and computer-aided design.

Surface Patterning

In our explorations, we developed multiple ways to pattern the surface of a DefeXtiles. Specifically, images can be encoded by the following approaches:

Variable Opacity: In order to achieve this effect, we designed the pattern in a CAD software as we would with a multi-material print. By splitting the print into two processes, we were able to tell the printer to print part of a pattern with a higher extrusion multiplier that yields a denser mesh, and the other portion of the pattern with a lower extrusion multiplier that yields a sparser mesh.

Varying Column Direction: By splitting the print into two processes, we could control the direction of the pillars for each of the two components.

Multi-Material: Using a multi-material printer we are able to print textiles with varying colors and properties. By using conductive PLA filament, we can integrate conductive traces into our textiles for capacitive sensing. This allows the traces to be precisely integrated into the textile. Additionally, since no material needs to be cut away, waste material is minimized.

Gaps (overhangs): Finally, gaps or cutouts in the textile can be printed without support materials.

Applications:

Lamp Shade

In this application, we demonstrate how multi-material printing allows us to, in a single print, produce a deformable DefeXtile lamp shade with solid conductive pads, which we use for two-wire transmit-receive capacitive sensing. The user can turn the lampshade by pinching the pleats together. The light can be made brighter by pulling the pleats further apart, or dimmer by pushing them together. The lampshade, the solid supports that suspend the lampshade around the bulb, and the conductive pads were all printed as one piece.

Tangible Online Shopping

An unnecessary cause of waste in the fashion industry is clothing ordered online that is returned due to poor fit or misrepresentation on websites. A recent study showed nearly 20-60% of clothing bought online is returned. While virtual dressing rooms are helping address this issue, the user is still unable to physically try on and interact with the garment before shipping. We envision two approaches that DefeXtiles can be used to minimize these unnecessary returns.

The first is to print out miniature versions of garments that look and feel like fabric so the user can get a better sense of the form than that afforded by a rigid print. Additionally, the dresses can be printed around a dress form based on a scan of the customer, allowing for them to physically check for proper fit. The dresses, without the dress-form, took 1-3 hours to print.

We also believe this could be useful for costume/fashion designers who render their design digitally. This would enable them to physically inspect and convey their ideas before moving on to physical fabrication.

4D Printing for Clothing Try-On

In the second approach, full-sized pre-forms of the garments can be tried on. In this scenario, a full-sized skirt is produced in a single print. This was achieved by pleating then compressing the textile to fit within the XY area of the printer. The skirt was then vertically segmented and nested to fit within the height limitations of the printer.

The skirt was designed similar to a telescope, with the bottom of one segment being wider than the top of the next. Once the try-on is complete, the skirt can be remelted and recycled into a new 3D printing filament to be used in the future.

Badminton Shuttlecock

For synthetic shuttlecocks, the presence of gaps in the net is critical to obtain proper aerodynamic properties, particularly the drag coefficient, that mirror those of feathered shuttle-cocks. As printing with TPU produces highly durable textiles, we were able to print tough shuttlecocks. The tail of the shuttlecock is printed as a DefeXtile to mimic feathers, and the head as a solid to mimic the rubber head.

Iron-On Pocket

The ability to heat-bond DefeXtiles allows users to augment existing garments. Here, we added a PLA pocket printed with a pleated structure so it can expand to accommodate more objects, and automatically retracts when those items are removed. This heat-bonding approach allows textiles of any size to be easily augmented.

Variations of Lace

Lace is a decorative fabric knit into complex web-like patterns. In this application, we show how our approach expands the aesthetic capabilities of 3D printers to produce intricate lace-like fabrics. We use different surface patterning primitives to generate lace with subtle nuances in how the pattern is encoded.

Tendon Actuator Toy

In this application, we develop a dancing person toy that can be printed in one piece with no post-processing. Both the tendons and joints are printed as DefeXtiles affording greater flexibility. In our approach, the rigid stiffeners, the textile flexures, and the embedded tendon are all printed at once without post-processing.

Conclusion:

This work has introduced a new approach to quickly print thin, flexible textiles composed of common 3D printing materials with an unmodified 3D printer. Our approach combines the flexible, thin, and breathable properties of textiles with the affordances of 3D printing: rapid iteration, hands-free fabrication, and computer-aided design. Through characterization, we demonstrate how our approach enables tuning of the mechanical and aesthetic properties through material and parameter selection. Through a series of applications, we demonstrated the potential applicability of our approach for smart textiles, tangible online shopping, toys, fabric design, and everyday life.

Due to the widespread use and accessibility of FDM printers, we envision this approach can immediately empower a wide audience with the ability to fabricate fabric into finished forms. We hope DefeXtiles can enrich HCI's maker toolbox and lower the barrier of entry to computational textile design