# overview This recitation represents a quick overview of textile processes and some applications that might be of interest for the <a href="https://fab.cba.mit.edu/classes/863.21/">htmaa</a> audience. Given the broad scope, lots of interesting textiles stuff won't get covered. I will try to provide pointers to more resources throughout! We're going to use a roughly hierarchical organization that follows the textile production process, going from raw material to fiber, to yarn, to textiles, and to textile assemblies/applications. Much of this recitation draws heavily from the <a href="https://akaspar.pages.cba.mit.edu/textiles-recitation/background.html"> 2019 HTMAA textiles recitation </a> by <a href="https://drive.google.com/file/d/16y695HSHqRDHlZZezP63iVEwnH9OCDJG/view"> Alexandre Kaspar</a>, <a href="https://www.kniterate.com/about/"> Alex Zimmer</a>, and <a href="http://www.carmelsnow.com/">Carmel Snow</a>. #### leaving out: history of textiles Some potential resources if you want to know more. As always, [Alex Kaspar's textiles recitation](https://akaspar.pages.cba.mit.edu/textiles-recitation/background.html#laver_costume_2020) contains more pointers. - [here is a book](https://www.worldcat.org/search?q=The+Golden+Thread%3A+How+Fabric+Changed+History+&qt=owc_search) - [and another one](https://www.nytimes.com/2020/11/10/books/review/the-fabric-of-civilization-virginia-postrel.html) # material to fibers to yarn We can split fibers into two categories: natural and manufactured. You might more commonly see natural vs. synthetic, which is another reasonable lens for looking at the fibers world. ## natural Within natural fibers, we can split into three categories: cellulosic (or plant derived), protein (or animal derived), and mineral. Plant and animal fibers are of the most relevance to making cloth. Common examples are shown below (image source: 3.S73, E. Meiklejohn) <img src="img/natural_synthetic.png"> While different fibers will have different processing steps (we wouldn't expect wool and cotton yarns to be produced identically), the steps from producing natural fibers/yarns follow similar-ish contours. We won't go into this too deeply, but here is a good video describing the linen cloth production process from flax to complete dyed cloth: <iframe width="560" height="315" src="https://www.youtube.com/embed/-ZrZZefkohE" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe> The main abstracted steps of this are extracting fiber from the raw material harvest (for cotton, this is called ginning), orienting+sorting fibers (carding), and eventually spinning into yarn. Some more info: - [carding](https://en.wikipedia.org/wiki/Carding)<br> - [carding machine](https://woolery.com/selecting-a-carder)<br> - [combing](https://en.wikipedia.org/wiki/Combing)<br> A historical example of cotton fiber processing (Richard Arkwright's Water Frame):<br> <iframe width="560" height="315" src="https://www.youtube.com/embed/AloWMoc-3WU" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe> ### Staple vs filament Something important to note in this process is that all natural fibers (except for silk) are short in length (mm to up to 10s of cm), so they require the mechanical process of spinning and bundling to form much longer lengths of yarn. The fiber is referred to as staple. The length of staple will also impact material and mechanical properties of the resultant yarn. Longer fibers are referred to as filament. Silk is typically filament fiber, and all synthetic fibers are produced as filament (though these are often later chopped and processed as staple). ## manufactured In the manufactured world of fibers, we can again split into a few categories: cellulosic, protein, mineral, and synthetic. Revisiting the categories from before: In the synthetics category are the fibers that we commonly think of as synthetic :p e.g. polyester, nylon. We have another class of cellulosic fibers here, such as rayon/viscose, because these fibers are made from regenerated or heavily processed Commercial synthetic fibers are made primarily through one of three methods: melt spinning, dry spinning, and wet spinning. These are illustrated in the below image. <p style="text-align:center;"> <img src="https://ars.els-cdn.com/content/image/3-s2.0-B9780857094995500106-f10-01-9780857094995.gif" alt="fiber spinning"> </p> In melt spinning, the polymer is melted and this liquid is extruded into fiber as it hardens. In dry spinning, the polymer is dissolved into solution, and the solution is evaporated out as the fiber is drawn. In wet spinning, the polymer is extruded into a coagulent bath, which either extracts the solvent or else catalyzes a crosslinking reaction to form a fiber. In each of these processes, fibers will typically be extruded through a spinneret. The cross section of the fibers can be fairly precisely controlled by changing the shape of the spinneret extrusion holes, and different material properties correspond to different shapes. For example, a fiber with a more star/gear shaped cross section made of a hydrophobic material will perform better wicking than a circular cross-section will. <p style="text-align:center;"> <img src="https://ars.els-cdn.com/content/image/3-s2.0-B9781855739208500011-f01-05-9781855739208.jpg" alt="fiber cross sections"> </p> The top row are natural fibers (cotton, wool, silk) and the bottom row are synthetic fibers. These fibers are extruded as filament (on the order of many km in length), though are not typically used at this length. Instead, post processing steps such as chopping are performed, and the resultant shorter lengths will be spun into yarns for material qualities more similar to natural fibers. Other post processing steps such as crimping can also be done (see below image). Crimping can be done to improve the thermal insulation of the yarn (more space occupying) or to incorporate mechanical stretch/elasticity into the resultant yarn. Some synthetic fibers will not be chopped, for example aramid (twaron, kevlar) fibers will be spun at longer lengths to preserve the high strength of the yarn (breaking fibers requires more strength than sliding them past each other). ### yarns Once we have a bunch of nice, oriented fibers, we want to produce yarn or thread. (The term thread is more commonly used to refer thread :p heading toward sewing applications, while it seems yarn is more standard for things headed toward getting turned into fabric). The production of yarn typically occurs through a process of twisting and plying. Twisting and plying are similar processes; twisting usually refers to going from fibers to yarn while plying refers to combining yarn. Twisting and plying will both have directionality, referred to as either S or Z twist (see image below). It is very common for yarns to be combined with each other using the opposite twist to help prevent unraveling (e.g. we have made 3 S twist yarns, which we will now spin together into one thicker Z twist yar). This image from the 2019 recitation illustrates this well: <img src="https://akaspar.pages.cba.mit.edu/textiles-recitation/figures/yarn-plies.jpg" alt="zs twist"> If you look closely at the inset, it looks like a bundle of three Z twist yarns plied with a S twist. [Studio Hilo](https://www.studiohilo.com/) has an open source CNC yarn twister that's very cool.<br> <p style="text-align:center;"> <img src="https://images.squarespace-cdn.com/content/v1/60dc17ecc64fbd25e1ef45ad/1633951194118-O61YVATVPKB2QAI45YAO/_DSC9145-Editprint.jpg?format=1500w" width=500 height=auto><br></p> It enables you to design and produce custom yarns that are in some senses asymmetric along the axis. The big exception to the yarn process is monofilament. Monofilament is single fiber that is intended to be used as is, so these will usually have wider diameter than fibers intended for yarns. Monofilament is not as commonly incorporated into garments, but has many other notable applications, including for fiber optics and as fishing line. Monofilament style fibers are also an active research area, which helps us segue into our next mini-section: <br> ### fun fibers We're going to quickly explore some exciting research things happening with fibers. #### Fibers@MIT Fibers@MIT uses a draw tower process to produce functional fibers with electronic properties. (This method is similar to the production process for optical fibers). Material is packed into a preform and then drawn into a fiber. The preform represents something akin to a larger version of the final fiber, i.e., the resultant cross section of the fiber can be pre-determined by the geometry of the preform (e.g. if desired, the fiber cross section could be exactly a miniaturized version of the preform). This strategy allows for the production of multi-material fibers with designed properties (e.g. piezoelectric), embedded electronics (e.g. diodes), or sensor style fibers with more "normal" properties (e.g. conductive fiber that can undergo high strains). <br> <p style="text-align:center;"> <img src="https://news.mit.edu/sites/default/files/styles/news_article__image_gallery/public/images/201105/20110519150154-1_0.jpg?itok=qiBenBY5"> </p> <br>Used preforms<br> <p style="text-align:center;"> <img src="https://media.springernature.com/lw685/springer-static/image/art%3A10.1038%2Fs41467-021-23628-5/MediaObjects/41467_2021_23628_Fig1_HTML.png?as=webp"><br> </p> Diagrams of strategy for embedding ICs into fibers. <br> #### Other cool thing: <p style="text-align:center;"> ![alt text](https://media.springernature.com/lw685/springer-static/image/art%3A10.1038%2Fs41586-021-03295-8/MediaObjects/41586_2021_3295_Fig1_HTML.png?as=webp) </p> #### Bio-fibers and electrospinning - [Electrospinning](https://en.wikipedia.org/wiki/Electrospinning#)<br> - <img src="https://upload.wikimedia.org/wikipedia/commons/thumb/c/ca/Electrospinning_Diagram.jpg/2560px-Electrospinning_Diagram.jpg" alt="electrospinning diagram" width=500 height=auto><br> - This is advantageous for producing extremely small diameter fiber (hundreds of nm) and so is commercially largely only used for producing filters. It is also of interest for wound dressings, tissue scaffolds, and drug delivery, as it is a good process for immobilizing cells. <br> Fibers containing living cells are also of interest in applications such as bioremediation, targeted drug delivery, and tissue scaffolding. Fibers/fiber mats/textiles containing bacteria specifically are fairly common as far as research applications go. <br> The fibers are typically electrospun or wet spun, with some applications using hydrogel coatings over "traditional" fibers. <br> - immobilized bacteria are easier to work with/model the behavior of and are more space efficient <br> - increased stability/activity of bacteria over long time lengths (up to ~weeks on its own) <br> - sheath/core fibers offer increased protections to the bacteria, enabling them to survive in environments they otherwise would not be able to in <br> - Example materials: <br> - [electrospun cyclodextrin containing bacteria](https://www.sciencedirect.com/science/article/pii/S0927776517306975) living bacteria in electrospun for bioremediation of heavy metals and reactive dye from wastewater, fiber matrix serves as a carrier and a feeding source, so encapsulation works better than free bacteria <br> - [electrospun Na-CMC and PEO w/ bacteria](https://www.futuremedicine.com/doi/full/10.2217/nnm-2018-0014) fibers with incorporated commensal bacteria for potential preventive treatment of the diabetic foot, shaping/cultivating skin microbiome to prevent against colonizing microorganisms, and enabling controlled release of viable bacteria. <br> - wetspun alginate fibers containing pigment producing e. coli in a monofilament woven construct: <img src="https://dam-prod.media.mit.edu/thumb/2020/06/22/edited-IMG_8600%20copy_Page_1.png.1400x1400.png" alt="wetspinning photo" width=500 height=auto><br> - A few more non-fibers bio textiles examples <br> - [Smart sensing fabrics for live bacteria detection](https://www.researchgate.net/publication/329224558_Smart_Sensing_Fabrics_for_Live_Bacteria_Detection) - [Light-controlled, high-resolution patterning of living engineered bacteria onto textiles, ceramics, and plastic](https://onlinelibrary.wiley.com/doi/abs/10.1002/adfm.201901788) # yarn to fabric We are going to primarily look at weaving and knitting processes (and we're not even going to go particularly in depth here haha). The below image is from <a href="https://akaspar.pages.cba.mit.edu/textiles-recitation/background.html#textile"> the 2019 htmaa textiles recitation</a>. <p style="text-align:center;"> <img src="https://akaspar.pages.cba.mit.edu/textiles-recitation/figures/topologies.jpg" alt="weaving, knitting"> </p> This shows the basic topologies for weaving, weft knitting, and warp knitting. ## weaving Weaving! (for a more coherent overview of weaving, I would go to <a href="https://akaspar.pages.cba.mit.edu/textiles-recitation/background.html#weaving">here</a>) <p style="text-align:center;"> <img src="https://i.pinimg.com/originals/20/63/69/2063696f2a5c4f2ba19a41b2d5ce9773.gif" alt="weaving diagram"> </p> This diagram shows a traditional loom set up. Individual yarns run along the length of the loom (the warp) and are pulled up and down using heddles. The space formed by one set of warps pulled up is the called the shed (this step is called shedding). The weft yarn runs through the shed (called weft insertion, traditionally, it is moved as a spool (shuttle)) and is packed using a reed (called beating up). As the cloth is formed, it gets collected in the chest beam and more warp is released from the warp beam. This image (sourc: <a href="https://akaspar.pages.cba.mit.edu/textiles-recitation/background.html#weaving">here</a>) shows the structure of the most common weave patterns. These structures can result in very different fabrics! E.g., satin weave is designed to produce glossy fabrics by having longer sections of "floating yarn" (continuous runs of yarn). <img src="https://akaspar.pages.cba.mit.edu/textiles-recitation/figures/weaves.png"> In Jaquard looms, each heddle is individually addressable and the process for choosing them is programmed and automatic. This enabled the production of cloth in a variety of highly complex patterns, with much less overhead for setting up new patterns. This video shows the operation of a historical Jaquard loom: <iframe width="560" height="315" src="https://www.youtube.com/embed/OlJns3fPItE" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe> <br> These days, knitting gets hyped a lot since you can produce continuous 3D shapes using it, but 3D weaving is also a thing! <img src="img/spacer_fabric.png"> These are some space filling woven fabrics. More interesting discussion of that here: <a href="http://cdn.intechopen.com/pdfs/36903/InTech-3d_woven_fabrics.pdf">3D Woven Fabrics</a><br> And this is a cool project: <iframe title="vimeo-player" src="https://player.vimeo.com/video/98775817?h=6b4c35d590" width="640" height="360" frameborder="0" allowfullscreen></iframe> Some other cool things: <a href="https://www.colorado.edu/atlas/loom-hacking">interactive loom </a> ## knitting <p style="text-align:center;"> <img src="https://akaspar.pages.cba.mit.edu/textiles-recitation/figures/topologies.jpg" alt="weaving, knitting"> </p><br> The two main knitting structures are weft knitting and warp knitting. In weft knitting, one continuous yarn is looped around itself, progressing row by row. In contrast, in warp knitting, multiple spools of yarn are knit together in columns. Weft knitting is what most of think of as "normal knitting". The process of producing a weft knit is illustrated below. There are two basic stitch types: a knit and a purl (flipping one results in the other)<br> <img src="https://upload.wikimedia.org/wikipedia/commons/2/20/Maschenbildung_1.jpg" alt="knitting"> <img src="https://www.researchgate.net/profile/Caroline-Schauer/publication/287149572/figure/fig1/AS:332697659559937@1456332711562/Self-folding-in-knits-A-knit-and-purl-stitches-B-transition-line-C-textile.png" width="500" height="auto"><br> <br> This is a diagram of a flat bed knitting machine that knits in a process similar to what's shown above. <img src="https://akaspar.pages.cba.mit.edu/textiles-recitation/figures/flat-bed.jpg" alt="flat-bed-knitting"> <iframe width="560" height="315" src="https://www.youtube.com/embed/BfX6hLAB7xU" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe> <iframe width="560" height="315" src="https://www.youtube.com/embed/fJaGl1mA39I" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe> <br> These are some useful animations for understanding what's going on. This is Alex Kaspar's page on machine knitting (also for HTMAA) (it's not the same page as the other ones! It's much more in depth on machine knitting, for anyone who's interested) https://akaspar.pages.cba.mit.edu/machine-knitting/ ### circular knitting <p style="text-align:center;"> <img src="https://akaspar.pages.cba.mit.edu/textiles-recitation/figures/circular-knitting.jpg"><br></p> A lot of knit fabric is produced on circular knitting machines. The one pictured above is a hobbyist style machine similar to one we have in the lab (THE TUBE MACHINE). T-shirt jersey, for example, is typically producing on large circular knitting machines and later cut into flat sheets. ### kniterate We have a (non?)functional knitting machine: the [kniterate](https://www.kniterate.com/) which may become available for you to use in htmaa. <br> <p style="text-align:center;"> <img src="https://i2.wp.com/www.kniterate.com/wp-content/uploads/2017/07/2_Kniterate_machine_front-yarn-scaled.jpg?resize=1024%2C683&ssl=1"><br> </p> ### Other cool things: cut and sew knit actuators: https://wyss.harvard.edu/technology/soft-robotic-glove/ <br> [self-folding knits](https://www.mdpi.com/2079-6439/3/4/575) <br> From CSAIL, computer aided knitting: <br> <iframe width="560" height="315" src="https://www.youtube.com/embed/q1lsnE5ANuM" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe> <br> KnitCandela: Knitted concrete system from Zaha Hadid and ETH Zurich <iframe width="852" height="479" src="https://www.youtube.com/embed/XW3-Xan_09w" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe> ## other methods of cloth production #### lace, crochet, knotting, non-wovens: felting, tufting, etc. See: https://akaspar.pages.cba.mit.edu/textiles-recitation/background.html#crochet (not covered in this recitation) ### Something important we're really leaving is stuff like dyeing and other post processing! Links: [] # Fabric assemblies By this, I mean sewing hahaha. (or: how to combine fabrics together (or with other things???)) ## Sewing ### Hand sewing https://www.instructables.com/Basic-Sewing-By-Hand-Tutorial/ <br> https://sew4home.com/hand-sewing-basics-tips-tools-techniques/ <h2>Sewing machine</h2> This is how it works: <p style="text-align:center;"> <video controls="" autoplay="" name="media"><source src="https://i.imgur.com/SaNHcqm.mp4" type="video/mp4"></video> <img src="https://doitbetteryourself.club/wp-content/uploads/2017/02/Triple-Straight-Stitch.jpg"> </p> A resource for <a href="https://thefinestthread.com/different-types-of-sewing-machines-explained/"> different sewing machines explained </a> A resrource for <a href="https://drive.google.com/drive/folders/16uhmMb8kE4P_vOSycr6XSa9zpmDijZSd"> how to sew, making sewing patterns, etc. </a> ### Embroidery We have an embroidery machine! Camron's tutorial: https://gitlab.cba.mit.edu/camblackburn/inkstitch Here is a #produced video on machine embroidery that emphasizes a few interesting techniques that could be of interest to you: <iframe width="560" height="315" src="https://www.youtube.com/embed/y9JsSTW7Te4" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe> Some examples of cool stuff: http://fab.cba.mit.edu/classes/863.18/Harvard/people/lara/week13.html [Embroidered Speakers Without Permanent Magnets](https://www.media.mit.edu/publications/sonoflex/) <iframe width="560" height="315" src="https://www.youtube.com/embed/JDuBuy0HntA" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe><br> <a href="http://cba.mit.edu/docs/theses/99.02.post.pdf"> Ernest Rehmatulla Post's CBA masters thesis </a> on embroidered circuitry <br> <a href="https://gitlab.cba.mit.edu/tlutz/sewing_recitation/tree/master">Tom Lutz's sewing recitation</a><br> <a href="https://github.com/CreativeInquiry/PEmbroider"> PEmbroider </a> computational embroidery library using Processing <br> [FIND agnes s slides on using this???] <a href="https://inkstitch.org/"> Ink/Stich</a> machine embroidery based on Inkscape <br> # more resources ### textiles and fibers - <a href="http://go.affoa.org/">Advanced Functional Fabrics of America</a> <br> - <a href="https://boltthreads.com/">Bolt Threads</a> <-- another angle on this type of product in this <a href="http://fibershed.org/wp-content/uploads/2018/09/ETC_SynbioFabricsReport_8Fsm.pdf">2018 review of synthetic biology practices in fast fashion<a/> <br> - <a href="https://www.colorado.edu/atlas/unstable-design-lab"> Unstable Design group at University of Colorado</a><br> - <a href="https://drexel.edu/functional-fabrics/research/projects/">Drexel University Functional Fabrics </a> <br> - <a href="https://textielmuseum.nl/en/textiellab-for-professionals/">Textiel Lab </a> <br> # INFLATABLES! This recitation is allegedly covering inflatables as well... uh Due to time constraints, I will point to Agnes's page from HTMAA 2019 wild card week instead haha: https://gitlab.cba.mit.edu/classes/863.19/site/-/wikis/wildcard/inflatables The short pitch is that inflatables are great for making something actually big (and also distressing)... Other fun points include (arguably) quieter, lighter weight actuation, and the form factor differences in inflated vs. non inflated states. During real recitation, we will also see a couple examples of actuated inflatables/pneumatic actuators (sort of). <img src="img/inflato.jpeg"> <img src="img/inflato_2.jpeg"> ### other inflatables resources soft robotics toolkit: https://softroboticstoolkit.com/ <br>