FYFD

Tag: manufacturing

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    Hand-Making Artist-Grade Pastels

    I’m constantly fascinated by the intersections of art and fluid mechanics. In this video, we get an inside look at a French atelier making artist-grade pastels using centuries-old methods. And although the final product doesn’t appear to have much to do with fluids — compared to, say, paint — the process behind each pastel involves a lot of fluid mechanics: mixing, pressing, drying, and rolling. It’s a neat look at how a niche product gets made. (Video and image credit: Business Insider)

    P.S. – Next week we’ll kick off our Paris Olympics coverage, but if you’d like a head start on the celebration, you can find our coverage of previous Olympics here. – Nicole

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    Liquid Metal Printing

    Engineers have developed a new 3D-printing technique that uses molten aluminum to quickly manufacture large-scale parts. This Liquid Metal Printing method deposits the metal into a bed of tiny glass beads, which hold the metal in place while it cools. In minutes, they can produce furniture-sized parts, but that speed comes at a cost in resolution; the printed parts are rough, but they have the strength to withstand further machining by bending, milling, etc. The process is also well-suited for reusing scrap metal. The team hopes their method will be a useful prototyping tool as well as a possible manufacturing technique in architecture and construction. (Image and video credit: MIT News; research credit: Z. Karsan et al.)

  • Liquid-in-Liquid Printing

    Liquid-in-Liquid Printing

    With 3D printing and other recent technologies, manufacturing options are always in flux. Here, researchers explore a method for printing a liquid inside of a liquid. Their materials are specially chosen such that the injected liquid forms an emulsion at its interface with the surrounding fluid. Once injection ends, the interface forms a wrinkly, viscoelastic skin that acts like a tube. As shown below, the tube is robust enough that it can be pumped full of yellow-dyed water without any loss of structure. (Image and research credit: P. Bazazi et al.)

  • Dip Coating

    Dip Coating

    Imagine dipping a rod into a liquid mixture filled with particles. When you pull the rod out, do particles stick to it? The answer depends on the relative importance of two sets of forces: the viscous drag as you lift the rod and adhesive power of surface tension. Scientists express this as a dimensionless ratio known as the capillary number.

    When the capillary number is small, viscous drag dominates, and any particles that try to stick to the rod get pulled away (upper left). But as you increase the capillary number, surface tension helps particles clump together and stick to the rod (lower left and right). If the surface tension forces are strong enough – meaning that the capillary number is high –  you can actually get multiple layers of particles adhering to the dipped surface. (Image and research credit: E. Dressaire et al.)

  • Using Instabilities for Manufacturing

    Using Instabilities for Manufacturing

    Manufacturing textured, flexible surfaces can be difficult, but researchers are exploring ways to use fluid dynamical instabilities to make the process easier. They begin with a pourable polymer mixture that cures and solidifies over time. By putting the mixture on a cylinder and rotating it, engineers trigger the Rayleigh-Taylor instability – the same instability that makes dense fluids sink into lighter ones. Here, the instability is driven not only by gravity but by the added acceleration caused by centrifugal force. It causes the fluid film to drain and form arrays of droplets, which then cure into dimples. The researchers can control the size, shape, and spacing of the droplets by changing parameters like the spin rate. And by repeating the process multiple times on the same piece, they can build up spikier shapes, like the ones shown on the poster below. (Image and research credit: J. Marthelot et al., poster)

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    Reminder for those at the APS DFD meeting! My talk is tonight at 5:10PM in Room B206. You’ll probably want to come early if you want a seat!