Tight clothes are not always ruled by dress choice. The global pandemic, for example, has underscored the need for face masks that effectively seal around the nose and mouth. But faces and their characteristics differ from person to person and can make one-size-fits-all face masks less effective. Well-fitting masks have proven to be a sought-after accessory.
Lavender Tessmer, a doctoral student in MIT’s Department of Architecture, has developed a new active fiber and engineered a process that, combined with a specific knitted textile architecture, uses heat to activate a mask to conform to a person’s face. individual. With standard textile equipment and the new customization process, any manufacturer can create a personalized mask.
Before coming to MIT in 2017, Tessmer had no formal introduction to textiles. She began working with Skylar Tibbits, an associate professor in the Department of Architecture and founder of the Self-Assembly Lab, where programmable materials — simple materials that can be activated to sense, respond, and transform — are among her research topics. . The following year, the lab purchased an industrial flat-knitting machine, ubiquitous in textile manufacturing across the world, and Tessmer set to work learning how to operate it.
“The learning curve is huge and there are endless things you can do with a machine like this,” says Tessmer.
His early start with the knitting machine was prescient for the work to come.
A step ahead
A few years before the pandemic, Tibbits’ lab received a grant from Advanced Functional Fibers of America (AFFOA) to develop “smarter textiles” that would be able to sense, react and transform. The research led to a partnership with Ministry of Supply – a fashion company specializing in high-tech clothing – to develop a new system of “smart textiles”. Created by MIT graduates, Ministry of Supply uses temperature-regulating materials to design and produce eco-friendly apparel for professionals.
In the spring of 2020, a confluence of events shifted their collaboration. The global pandemic forced businesses to close in March; the Department of Architecture has issued a call for proposals to fund research positions for students to work with faculty on “crisis-related research,” including design responses to the pandemic; and the need for masks to protect first responders and the general public became apparent. Tibbits’ research received funding from the ministry.
“Lavender was already trying to make textile garments with a custom fit, so we could quickly move into making custom masks,” says Tibbits. “But the main challenge with any customization is that you can’t make every mask unique. It becomes a factory logistics problem. You must be able to mass produce them. Customers don’t want to wait weeks or months for their unique mask. »
How, then, is a mass-produced mask suited to an individual face?
“The lavender created the knitted structure – the architecture – of the mask,” says Tibbits. “Material properties alone do not lead to precise transformation behavior. They are basically two or three dimensional knit structures, and with each stitch you can change the structure and materials.
Tessmer also developed one of two active fibers (the other was already commercially available) needed to react to heat so that the fabric could be controlled in a predictable way.
“There had to be a clear relationship between the amount of heat applied, the method of application with the robot, and achieving a predictable result in the dimensional transformation of the fabric,” says Tessmer. “It was an iterative process between developing the multi-layered fabric, measuring its dimensional change, and then allowing the robot to apply heat in a repeatable and predictable way.”
Already in the public domain, there were guidelines for existing ranges of measurements of human facial features. The mask’s starting shape is large enough for almost any face before it’s transformed and customized. From there, Tessmer input the dimensions of an individual’s face and the knit masks were activated with a robotic arm fitted with a heat gun that applies heat in specific patterns to precisely fit them to the body’s measurements. face.
Need for masks motivated by Covid
With their retail operations shut down at the start of the pandemic, the Ministry of Supply shifted from making clothes to making face masks.
“The strength of Lavender and Skylar’s work is that it takes advantage of additive manufacturing techniques, which can be brought into production very quickly,” says Gihan Amarasiriwardena ’11, Ministry of Supply co-founder and company president. . “Working with the self-assembly lab, we were able to design, test and develop a mask in five days and produce 4,000 masks in two weeks for healthcare workers thanks to our ability to use 3D computerized knitting. I think this will be a key asset in being able to repurpose existing materials into masks very quickly in the future.
“The goal was to transform a mask to fit perfectly on anyone’s face, which is a major challenge with masks and other garments,” says Tibbits. “No one has really figured out how to do this other than hiring a tailor or having a lot of standard sizes that don’t fit perfectly.”
It’s important to note that Tessmer and Tibbits’ work focused on the fit of a mask, not the properties required for a mask’s material to filter out airborne particles – although that a standard filter can be included to improve its efficiency. The masks are also reusable and washable.
“Our goal was better fibers and a controllable, repeatable process to create a bespoke mask,” says Tessmer. “We created masks for nine different people to demonstrate the effectiveness of the process.”
Last fall, an article they co-authored, “Custom Knit Masks: Programmable Shape Change for a Custom Fit,” provided instructions for creating “truly customizable masks” that conform to each person’s unique facial features. individual. The Association for Computer-Aided Design in Architecture (ACADIA) awarded Tessmer and Tibbits its Best Paper Award for this groundbreaking work.
“The award recognizes that the article is exemplary, presenting innovative research with a substantial contribution to the field described,” the judges noted in their remarks. “In addition to demonstrating rigorous research methods and disciplinary expertise, the paper is also well-written, bringing new insights to the ACADIA community and beyond.
The evolution of SARS-CoV-2 variants suggests the need for high-quality masks will persist, and the US Centers for Disease Control continues to support their use. Amarasiriwardena believes consumer interest and need for masks will continue to exist, if only seasonally when people are indoors more frequently. He says the fit and comfort of a mask is the second most important question customers ask, after the effectiveness of the filter media.
“Overall efficiency is tied to fit, which is unlocked by custom manufacturing,” says Amarasiriwardena. “The Self-Assembly Lab has really pushed the boundaries of additive manufacturing, and their recent work in textiles combines their expertise in ‘hacking’ CAD-CAM workflows to create truly new flexible products. While much of the attention has focused on 3D printing durable goods, their innovation in textiles shows wide application of self-assembly technology.
Tessmer says the masks were a great case study because they’ve been a sought-after accessory in recent years, and there have been notable issues with how the masks fit. She would like to apply the process to other types of clothing and accessories, such as sweaters and shoes.
“At the end of every project, there are always things you find that need improvement,” Tessmer says. “There are a lot of future fabric developments, for example. But I’m happy with the project because it’s a working proof of concept for my idea, and I’m confident it works.