Accordions Pineapples Artificial Joints
The distinctive sound of the accordion appears in almost every kind of music. The piano-style keyboard on the right-hand side produces the melody, while the buttons on the left produce the chord accompaniment. In between are bellows that force air through reeds, producing that unmistakable accordion sound. the accordion is a beautiful and complex instrument. It contains up to 10 sets of steel reeds with different pitches. Each reed set goes into a wooden block. Under every section is an opening called a tone hole. The bellows drives air through it, vibrating the reed above to produce a musical note. These leather-and-plastic pads cover the slots on the accordion's aluminum reed plates. Each plate holds two reeds. Both reeds produce the same note-- one when you push the bellows, the other when you pull. They now apply a special wax to secure the reeds to the block. If they used glue, they wouldn't be able to remove the plate should a reed ever need repair. Each reed played corresponds to a specific note or chord. To assemble the keyboard, they begin with a lever made of fiberglass-reinforced plastic. It has a wooden core to give the keys sufficient weight. A long metal lever goes into the top. When the musician presses a key, its mechanism unblocks the corresponding tone hole, allowing air to flow inside and vibrate one of the plate's two reeds. Next, they drive in the steel axle on which the keys pivot. Then they apply suction to a keyboard-size tray. In it, they line up the plastic key tops. In top-of-the-line models, the white key tops are made of celluloid. With the suction holding the keys down, it's just a matter of flipping the tray and clamping it onto the keyboard frame. The tops adhere to the levers, which have since received a coat of glue. After about an hour, the glue is dry. They cut the suction, and the keyboard is finger-ready. Meanwhile, the reed blocks are in the hands of a tuning specialist, who pumps air with a foot pedal to vibrate the reeds one at a time. He compares each note to a reference tone from a tuning apparatus and files the reeds gradually until their pitches match. Now for the button keyboard. Starting with the valves, they install a wooden pallet over each tone hole. To that, they glue a steel lever. Then to that, they connect a brass rake. When the rake moves, it pulls the lever, which opens the valve, unblocking the tone hole. Air enters and vibrates the reed, producing the note. Each keyboard button opens three valves. That's why pushing one button produces a three-note chord. With the complex connections between buttons and reeds complete, the reed blocks go into a celluloid-on-plywood housing. It'll attach to the bellows made of strong pleated cardboard reinforced with leather and metal corner protectors. but before permanently attaching the bellows, all the reeds have to undergo a final and very extensive tuning adjustment. an accordion can have up to 600 reeds, so this meticulous reed-by-reed tuning can take up to 16 hours. they now pin the bellows' wood frame ends to the treble and bass housings. Then they cap each housing with a cloth-covered grille to keep out dust. After polishing the accordion to a high-gloss finish, it's time for a musical road test in white gloves. There's no sense in leaving fingerprints on that exquisitely polished surface. With the test checklist complete, the inspector signs off on it. You can't say this job's all work and no play. the pineapple is native to south america, but colonization spread it to other tropical areas. The latin name for pineapple is "ananas," which comes from nana, what the natives called the plant. The english word "pineapple" came from the european explorers who thought that this strange but delicious fruit looked like a giant pinecone. Pineapples need temperatures between 73 and 86 degrees fahrenheit and full sun. It takes seven months for the pineapple plant to produce a bunch of little reddish-purple flowers. At this first bloom, as it's called, farmers spray the plant with ethylene, a natural gas that stimulates full flowering. As that happens, the stem of the flower bunch gradually thickens and becomes bulbous. This is the pineapple. Five months after first bloom, a year since the last harvest, a fresh crop of pineapples is ripe for the picking. But not before the farm has tested samples to make sure the sweetness level is just right. This is prickly business, so the workers have to wear gloves, long sleeves, safety glasses, and rubber boots. The pineapples travel from the field to the factory upside down. That way the crown of leaves bears the weight of the fruit during the bumpy ride. Upon arrival at the factory, the pineapples go through a 10-step cleaning in chlorinated water. This washes away insects and frog eggs. Frogs like to lay their eggs in pineapple crowns. A final rinse with clean water removes any chlorine residue. Now workers classify the pineapples and cut off misshapen crowns. A first-class pineapple has a straight crown and no more than three damaged eyes, those diamond shapes on the peel. If a pineapple passes the first-class test, it's fit for export. Second-class sells on the domestic market. Third becomes dried fruit, and fourth, juice. At the drying plant for third-class pineapples, workers first chop off the crown, and then about two inches from the bottom end. With a coring machine, they remove the pineapple's hard center called the heart. Knife-wielding employees work their magic, each peeling five to seven pineapples per minute. The coarse skin dulls the blades quickly, so they have to keep sharpening their knives about every half-hour. The peeled pineapples then move on to a slicing machine, which produces slices a little more than a half-inch thick. The average pineapple yields about seven slices. Workers place the slices on large trays... Load the trays on large racks... Then roll the racks into a gas oven. The slices bake for 24 hours between 147 and 151 degrees fahrenheit. This dries them almost completely. When they come out of the oven, their moisture level is 6%, just enough to ensure the slices are chewy. From the oven to packaging. These preservative-free dried pineapple slices stay fresh in the package for 18 months. Now back to the pineapple factory, where the first-class fruits pass under a shower of hot wax. Fans cool and harden the wax into a coating that creates an air barrier. This slows the ripening process, ensuring the pineapples don't overripen by the time they arrive at their export destination. Last stop is the packaging and labeling department. Workers box pineapples with and without crowns separately. Those with crowns are for export. The crownless ones go to a canning factory to be sliced, diced, or crushed. From the field to your table, pineapples are the fruit of many people's labors. Artificial body parts used to be the stuff of science fiction. Nowadays artificial joints, at least, are routine. An artificial joint is a prosthesis that surgeons insert to replace diseased or worn-out bone and cartilage. In nearly all cases, an artificial joint relieves pain and improves the range of motion. From your knees and hips to your wrists, elbow, and shoulders, if your joints go, you can replace them. An artificial joint has both metal and plastic components. The metal acts as bone, the plastic is cartilage. This factory makes the metal parts three ways. It either casts them, forges them, or machines them. Casting is the most complex method. The first step is to pressure-inject melted wax into an aluminum mold. This makes a pattern, a wax replica of the metal part. Now they build the mold for casting the part in metal. Workers fuse a group of patterns with hot wax to a holder also made of wax. The patterns will shape the cavity in the molds. They submerge the patterns in a thick liquid ceramic which soon hardens into a fragile shell around the wax. Then they sprinkle the shell with a mixture of two minerals-- silica sand and zircon-- to build up a strengthening crust. The shells now go into a furnace for about two hours. The intense heat hardens them and incinerates the wax inside, leaving a cavity in the pattern shape. The shells are now molds strong enough to withstand molten metal. That metal is cobalt chrome. In this crucible, the chrome liquefies in about 10 minutes. They remove the molds from the furnace and lock them to the top of another one above the crucible. Then they flip it over. The molten metal flows from the crucible into the molds. It solidifies within two minutes. Then they transfer the hot molds to a cooling bin. Cold air flows around them for about two hours until they're finally cool enough to handle. Then workers mount each tree on an automated machine that works like a jackhammer. Each mold disintegrates, freeing the cast-metal part inside. They use a saw to separate the parts from the tree, then a grinding belt to remove any unnecessary metal that hardened in the channels. Next, they laser-engrave a unique serial number on each part for tracking purposes. Every part undergoes a thorough inspection. They dust the part with fluorescent powder, then rinse it off. Powder residue settles in any flaw and glows under ultraviolet light. After inspection, they buff every part until the metal's so shiny, you can see a reflection. Another method for making metal parts is forging. They use a titanium alloy, which is more flexible than cobalt chrome, making it better suited for hip joints, in particular. They clean the metal, then heat it in a 2,200-degree furnace. This 660-ton press forms one piece at a time into a preliminary shape. Then they move it to the next die and stamp twice to refine and then finalize the shape. The last stamping on the third die trims off excess metal and adds detail. The forged part now goes into a sandblasting chamber which cleans the metal and gives the surface a matte finish. Here's what the part looks like before sandblasting and after. Now a computer-guided milling machine smooths away the rough edge that trimming the excess metal left behind. This removes all but the last bit, so they get rid of that with a sanding belt. But sanding leaves metal residue behind. So the parts now go for a bath in a water-based citric solution. The metal surface has to be perfectly clean in order to stamp on the serial number in ink. Quite a difference before cleaning and after. Each and every metal part, whether forged or cast, goes to the quality control department. There, using digital calipers, an inspector checks all the dimensions, then examines the part under a magnifying glass. So far we've seen two of the ways they make the metal parts of an artificial joint-- casting and forging. The third method is coming right up. The metal portion of an artificial joint plays the role of bone, while the plastic portion mimics cartilage. However, the plastic isn't your run-of-the-mill plastic. It's medical-grade polyethylene, meaning it's formulated to be lightweight, but also extremely durable so that it withstands years of wear and tear within the body. The type of metal they use to make the bone portion of an artificial joint depends on how flexible that joint has to be. A knee joint requires less elasticity, so they mold it out of cobalt chrome. A hip joint, on the other hand, needs to be more bendable. So for that, they use titanium. They either forge the shape in a press or mount the titanium block on a computer-guided mill. Under a steady shower of lubricant, the mill's 20-odd machining tools carve the block from all angles. After a primary rough machining, the mill's precision tools finalize the shape. From start to finish, machining just one part takes about half an hour. Now a robot takes over. It runs the part against a series of sanding belts, their grits progressing from rough to fine. This removes marks the machining tools left on the metal and polishes the surface to a mirror finish. The robot can't reach the edges, so a worker sands them manually and verifies the dimensions. Then the parts go for a thorough cleaning. The factory puts random samples through wear testing. The machines simulate joint movement, complete with fake joint fluid. The factory sprays some parts with titanium powder to help bone tissue to cling to them. This machine, called an optical comparator, projects an image of the part's coated outline against a technically perfect template. The technician makes sure the part and the template match. To become an artificial joint, the metal bone now needs its plastic cartilage. That requires polyethylene powder. A technician weighs out a specific amount, puts it in the outer sleeve of a mold, then inserts the mold's inner piece. The technician loads the mold into a press that applies both pressure and heat-- 374 degrees fahrenheit. The powder gets squeezed between the mold's two parts and turns into solid plastic. Using various instruments, they measure the molded part to ensure all its dimensions are exact. Now a computer-guided machining tool carves the grooves into which the metal part will slide. These details are far too intricate for a mold to shape. Then some final measurements to make sure the finished part adheres to the engineering specifications. Random samples undergo fatigue testing equivalent to 10 years of wear. Some plastic parts are just too complex to be molded outright, so, instead, the factory molds a block of plastic, then machines it. The block spins on a lathe as various computer-guided tools shape it. Samples of these also undergo wear testing. After a specific number of movements over a specific time period, technicians remove the parts and weigh them. By comparing to the starting weight, they can calculate how much plastic has worn off. The packaging room is what they call a clean room, meaning the air runs through a filter system to keep out dust and dirt. Workers pack the artificial joints against foam to protect the metal surface, because even the tiniest scratch can cause premature wear. After heat-sealing the packages, the factory ships them off to a sterilization plant. There, powerful gamma rays penetrate right through the packaging and kill off any bacteria that might be lurking inside. Make no bones about it, these joints may be artificial, but the movement they restore is as real as it gets.