Thermoplastic Fire Helmets Basketry Sculptures Coffee Roasters
Thermoplastic fire helmets are lightweight, but that doesn't mean they aren't tough. Because of their chemical composition, these plastic helmets remain sturdy, even when exposed to temperatures of over 500 degrees fahrenheit. Developed in the 1970s, the helmets have become standard issue at many fire stations. There are few situations more dangerous than entering a burning building. Thermoplastic fire helmets weigh substantially less than other alternatives. These helmets are one piece of equipment that won't slow down the rescue mission. Production starts with a special blend of thermoplastic pellets. A vacuum pulls the pellets into a hopper. The pellets then flow into an injection-molding machine. It melts and molds the pellets into the shape of a fire helmet. A robot retrieves the helmet and transfers it to a cooling station. A worker then clips off plastic that solidified as it flowed through a channel and into the mold. This unwanted bit is called sprue. She wipes off fingerprints and inspects the condition of the helmet shell. The next worker trims the brim to remove excess plastic that formed when the mold closed. For this process, he uses a blade with a curved edge. Next, he applies reflective strips that will allow the firefighter to be seen in the dark. He drills holes for attaching either goggles or face shields. And the worker adds a last reflective strip. He screws a support plate for the i.d. shield to the front of the helmet shell. He uses plastic screws rather than metal because metal is electrically conductive and would put the firefighter at risk in the event of electrical sparking during a fire. Another worker now applies labels to the inside of the helmet shell. The labels indicate that this model of fire helmet is in compliance with the safety requirements. The worker inserts high-density foam padding in the helmet shell. The padded cap will cushion the wearer from the force of an impact. This web of straps will serve as a suspension liner and will also support the helmet on the wearer's head. Another worker installs a ratchet system for adjusting the fit of the liner to the firefighter's head. Positioned at the nape of the neck, the firefighter can turn the knob to pull the suspension web tighter. Attachments on the suspension liner fit into sockets on the helmet to lock it in place. He fastens the chin strap to the helmet by wrapping the ends around molded struts on both sides of the shell. The chin strap has a quick-release button in the event that the firefighter has to remove the helmet fast. Another worker now folds up flame-resistant earflaps. The flaps are equipped with hooked and looped fastening strips that fit to the helmet. He sets the earflaps aside while he inserts snaps for goggles into brackets on the helmet. He screws the snaps snugly to the helmet. The worker then wraps the fire-and-fog-resistant goggles around the helmet and snaps them to it. He tucks the maintenance instructions into the helmet, followed by the folded earflaps. This thermoplastic fire helmet is now complete, but there's still one last bit of official business. The worker screws the large leather i.d. shield to the support plate. The shield bears the name of the fire department and a symbol that denotes rank. This fire helmet is now ready for duty. It will be one of the first things the firefighter reaches for when he or she gets an emergency call. Contemporary artists are challenging our perception of basketry. Focusing on form rather than function, artisans are weaving grasses and other fibers into sculptural art. These basketry sculptures usually aren't meant to contain anything. Instead, they're meant to capture and hold our attention. Is it art, or is it a basket? A basketry sculpture is both. It celebrates the tradition of the craft while elevating basketry to an art form. Materials for a basketry sculpture can include a mix of thing, from natural fibers, to metallic pieces, wire, and beads. Soaking fibers like palm-tree strands in hot water will soften them and make the fibers flexible enough for weaving, but they won't lose their interesting crinkly texture. About two hours in, the artist checks the suppleness of the fibers. They can now be bent without breaking, but they need a bit more softening up. So she covers the fibers with plastic and leaves them to soak a little longer. She turns her attention to the sculpture's centerpiece, which will be made of copper. She draws a design onto the copper's protective plastic liner. Using metal shears, she cuts out the shape. The artist peels off the plastic liner that has protected the copper, revealing the glossy, untarnished surface. She now places the copper above a bag full of small pellets and pounds it using a nylon mallet. This process gives the copper an aged, hammered texture. She gives some areas on the other side the same treatment. The hammering also bowls out the profile of the piece. Using a marker, the artist draws a line about 1/3 of an inch in from the edge. She marks dots onto this newly defined border, spacing them evenly apart. She then punches holes through all the dots, using a lever-operated drill press. She cuts out the space between the holes, and this process creates separate tabs for each hole. The artisan now bends back the tabs, following the marked line. The application of a clear powder coat prevents tarnishing. After a few hours, the palm strands are now sufficiently softened. She retrieves the strands from the hot-water soak and sets them aside. The artist returns to the copper centerpiece and begins to weave, starting with rattan reeds that have also soaked to make them more pliable. She pulls the reeds through the tabs and intercrosses them so that they fan out in two directions. She then braids cotton string against the centerpiece. This creates a neat and sturdy border all the way around. She clips clothespins to the rattan to hold the braided border in place against the centerpiece. She then trims the ends of the strings. Next, the artist weaves rattan reeds parallel to the cotton braid, entwining them with the reeds that extend outward. She creates one row of these rigid fibers for structure. She's now ready for the palm strands. After the soaking, the strands remain soft and pliable for many hours, so she doesn't have to rush the work. As she continues, she alternates rows of palm and rattan fibers. The different textures add visual interest to the basketry sculpture. It will take two months to complete this work. When the basketry work is done, the artist takes the piece outside and airbrushes them with acrylic paint. She sometimes relies on a metal template to more evenly define the paint border. It's the finishing touch to the basketry sculpture, and now it's up to the public to understand the story that the artist has woven. The earliest tools for roasting coffee beans were pans you would hold over hot coals or an open fire, but, today, coffee roasting is a far more sophisticated process, using large, often fully automated machines with built-in gas burners that heat air to roast the beans. This coffee roaster is both programmable and manually adjustable by touch panel. The roast master can tailor the temperature and roasting time to influence flavor, acidity, and other characteristics of coffee. To shape the roast chamber, workers feed a sheet of stainless steel through a sheet-metal roll. The roast chamber is the drum in which the beans roast by convection heat. The next step is to weld the rolled sheet into a cylinder. Then workers grind and polish the welds until they're flat, smooth, and shiny. Another worker makes the cooling tray in a similar way, but with a support band welded to the top. The cooling tray is the drum into which the hot beans drop when they exit the roast chamber. Stirring arms circulate the beans as a fan draws air through the tray to cool the hot beans. Certain parts of the roaster are cut from a stainless-steel sheet. Stainless steel is the ideal material not only because it's stylish, but also because it's durable and corrosion-resistant. This computer-guided laser cutter is slicing out a safety component called the heat shield, which prevents the roast master from accidentally touching a hot surface. The heat shield, like many other parts cut from stainless-steel sheets, has to be formed to a very precise shape. A worker bends angles and curves into the metal with a press brake. Another component, the trier, lets you draw a sample of beans during roasting. A craftsman constructs the trier by welding various smaller parts to a piece of stainless-steel tube, then meticulously grinding and polishing the welds until they're smooth. This high-pressure water-jet cutter also cuts parts from stainless-steel sheets. This component is one of six flights, which is part of the paddle that lifts and mixes the beans inside the roast chamber so that they roast evenly. To form the flights to the required shape, a worker curves them one at a time in a press. Next, the welder places all the paddle components into a specialized fixture, which positions them correctly. First, he aligns the spokes to the paddle shaft. Then he welds the parts in place. He positions the flights, clamps them securely, and welds them on. The combination of inner and outer flights lifts the beans into the airflow, ensuring the beans roast evenly. A custom-designed grinding machine hones the flights to produce a small clearance of around 1/10 of an inch between the edge of the paddle and the wall of the roast chamber. This design ensures the paddle is wide enough to pick up every last coffee bean without touching the wall while rotating. Once they install the paddle, a worker closes up the roast chamber with a faceplate. Alignment pins ensure the faceplate is properly positioned. The paddle shaft protrudes through a bearing in the faceplate. The assembly team uses a hoist to lift the heavy chamber and position it on top of the coffee roaster's stainless-steel support frame. They install the heat shield that was cut by the laser cutter and bent to shape in the press brake. On top, the assembly team mounts the machine's funnel-shaped hopper. The hopper feeds the unroasted coffee beans to the roast chamber below. The hopper's lid has a tube, which connects to a vacuum system that draws the coffee beans up through a plastic hose. On the front of the roasting chamber, an assembler hangs a hinged discharge door that has a viewing window. He plugs in a sensor that measures the temperature of the beans in the roasting chamber and sends that information to the machine's computer. More to come after this coffee break. This coffee-roasting machine has three additional temperature sensors that send data to the computer. These sensors measure the temperature of the air entering and exiting the roast chamber and the temperature of the clean air exhausting from the machine after the burner incinerates the smoke generated by the roasting process. Workers continue assembly by installing the cooling tray beneath the discharge door of the roasting chamber. The cooling tray sits on a support frame, which contains a motor that turns the stirring arms inside the tray. At the back of the machine, a worker installs the tray's cooling fan and the motor that drives it. This gauge measures the pressure of the air that mixes with the gas going into the machine's burner. Next, they install the circulation fan. The fan is designed to withstand high heat and move air efficiently throughout the coffee roaster. The bottom end of this stainless-steel tube connects to a vacuum motor. The top end connects to the tube protruding from the feed hopper's lid. To fill the roasting chamber, the vacuum motor sucks the raw green coffee beans up into the hopper, which drops the beans into the chamber, where, as they roast, their papery skin, called the chaff, breaks off. This separating device, known as a cyclone, connects to the circulation fan. The fan blows hot air returning from the roasting chamber into the cyclone at high velocity. The air circulates in a downward spiral past the burner at the base of the cyclone, incinerating the smoke. This also draws the chaff out of the air into a barrel. Nozzles spray water on the chaff to prevent it from catching fire, which is a common hazard with traditional coffee roasters. The circulation fan then forces the clean, hot air up and out the top of the cyclone, through this "s"-shaped, insulated air duct, back into the roasting chamber. A technician in the factory's electrical department assembles the machine's control panel. Among other components, the circuitry runs control systems and the machine's six electric motors, which operate moving parts, such as the bean-drawing vacuum motor, the circulation fan, the cooling-tray fan, the roasting-chamber paddle, and cooling-tray stirring arms. Workers then install the control panel in a cabinet on the side of the machine. They connect all the wires. They mount the machine's computer adjacent to the control-panel cabinet. Next, a worker assembles the cooling-tray system. A motor under the tray drives the stirring arms. The hot roasted coffee beans sit on top of the stainless-steel screen. The cooling fan pulls ambient air through the beans, down through the openings of the screen, then out an exhaust pipe to the outdoors. The stirring arms move the beans around so that they cool quickly and evenly, which prevents the beans from continuing to roast. The factory runs every finished coffee roaster through multiple test roasts. After heating the roast chamber to a specific temperature, the operator uses the touch screen to release the beans into the chamber. The hot air travels from the cyclone to the roast chamber, then through a return pipe back to the cyclone, where it's cleaned and sent back to the chamber. To know when to manually end the roast cycle, the operator views, smells, and listens to the beans. That's because coffee beans make crackling noises as they expand and shed their chaff. The machine can also be set to end the roast cycle automatically when the beans reach their target temperature. A trapdoor opens to draw in ambient air. This cooler air pushes smoke in the roasting chamber up to the cyclone for incineration. The computer can automatically open the roast chamber's discharge door, or the operator can do so manually. As soon as the roasted coffee beans drop into the cooling tray, the stirring arms and cooling fan automatically start up. If the beans are perfectly roasted, the machine is ready to be shipped to a coffee-roasting business.