Sanders Solid Terrain Models Stucco High
Most experts will tell you that the key to the perfect paint job or wood-refinishing job is to prep the surface properly before applying the paint or wood stain. That requires sanding to remove old finishes and to level uneven areas. The easiest way to do that is with a motorized sander. Professional-caliber sanders are typically pneumatic, meaning you plug them into an air compressor. Air-driven tools are more powerful than tools than run on electricity. This type of sander is called a straight line, because the pad to which you attach sandpaper moves in a straight line back and forth. Many of the tool's components are made of powdered metal, then machined to exact dimensions on a computer-guided lathe. Powdered metal is iron powder that's compacted with high pressure and heated in a furnace to bond the particles into a solid part. Sometimes they further strengthen the powdered metal by infusing it with copper in the furnace. Using an induction welder, which heats the metal with an electric current, they fuse a powdered-metal gear to each end of a steel shaft by melting on silver. This constructs the sander's timing driveshaft, the regulating component that makes each stroke of the sanding pad just under an inch long. Heating the metal softens it, so they now cool the timing driveshaft in oil. This quenching hardens the component. Meanwhile, they coat a sheet of aluminum rectangles with industrial-strength contact adhesive. Each rectangle is a base for a rubber sanding pad. The rectangular pad, which they coat with the same adhesive, is 6 1/2 millimeters thick, the same dimensions as the base with identical holes for the mounting screws. Once the adhesive becomes tacky, they mate the base to the pad. Using a small pneumatic press, they force out trapped air to ensure a thorough bond. Elsewhere in the factory, they paint the recessed lettering of the polished aluminum plates, two per sander, which bear the manufacturer's name. Once all the remaining components are prepared, technicians begin the assembly. First, the motor's piston. They place the piston rack in an arbor press and push a plastic piece onto each end. Then, on each end piece, they mount a piston ring made of a proprietary wear-resistant material. They insert the now-assembled piston into the sander's aluminum motor block. The ring creates a tight seal to prevent air leakage. Next, a technician installs the timing driveshaft and the idler gear shaft, pressing the gears of both into the piston rack's teeth. The powdered-metal counterweight goes on each side to balance the piston rack, then guides made of that proprietary material to align and lubricate the counterweights. A second set of anti-wear guides goes in the lower part of the motor block. These help balance the sanding pad. Then the start of the valve system, which controls the entry of compressed air into the sander. At the front of the motor block, they install a paper gasket to prevent air leakage, then seal it with an aluminum end plate. Continuing with the valve system, they install the components, which control the timing of the pistons' back-and-forth motion. After sealing the top with a cap, they install the air-valve block, then the handle, which contains the inlet to which the air compressor connects. The handle squeeze trigger is mounted to the cap above the handle. They install the counterweight for the pad. Here, you can see the two shafts the piston rack rotates. Workers connect them to an aluminum drive shoe, which will move back and forth. A pair of side rails holds the drive shoe in place. Where the air exits the tool, they install a muffler made of porous plastic. Finally, when the technician screws the base to the drive shoe, the chain is complete. Compressed air moves the piston, which rotates the shafts, which moves the drive shoe holding the rubber pad with sandpaper. This pneumatic sander is ready to level and smooth a surface in seconds flat. A solid terrain model, "stm" for short, is an exact, three-dimensional, miniature replica of a geographic area. Stms are indispensable tools for museums, visitor centers, and for planning everything from industrial projects to military operations. To create a solid terrain model, the first step is to gather data via satellites and aircraft. Two types of data--  color photographs of the surface showing the precise location of vegetation, rock, buildings, and so on, and elevation measurements, taken with lasers and other equipment. A cartographer digitally merges the black and white elevation diagrams with the color photos and adds artwork for roads and place names. He produces a 3-d computer model of the area. This model will guide the machines that manufacture the physical model out of a block of polyurethane foam. Foam is a durable material and lightweight, making the model easy to transport. A computer-guided cutting machine first shapes a ledge around the block's perimeter. This is for mounting the model on a frame. Then the machine reads the computer model's elevation files and carves a miniature replica of those elevations into foam. The machine first does a rough cut. Then--  and this takes much longer-- it carves the fine details. Depending on the complexity of the terrain, cutting the elevations into the foam can take just a few hours or several days. When the cutting's finished, the technician cleans off the foam dust with compressed air and a brush. The foam goes into a spray booth where it first receives a coat of primer to seal the porous surface, then multiple layers of special coatings to make images printed on the surface sharp and vibrant. Once the coating's dry--  that takes about a day-- technicians put the model into a custom-designed inkjet printer, which reads the computer model's photograph file. Just like an ordinary printer, this printer produces a multitude of shades from just four basic colors-- black, yellow, magenta, and cyan. The jets pass just a few millimeters above the model, emitting one microscopic drop of ink at a time at precisely the correct location. The end result is a miniature replica of what the surface looks like in real life. Other workers, meanwhile, construct a sturdy frame for the model by gluing, clamping, and nailing together four lengths of oak. This frame will protect the model from damage and make it easier to lift and move. Once the glue dries, they remove the clamps, and with a saw, trim each corner to a 45-degree angle. Then they round the edges with a sander. They complete the frame by protecting the wood with a coat of clear polyurethane. When that dries, they spread glue onto the frame's inside edge. Then they position the model so that the ledge along its perimeter sits on top of the frame. After printing, they spray the model with clear polyurethane or lacquer. The protective finish allows people to now touch the model without damaging it. Sometimes, an area they're modeling has buildings, bridges, or other structures. When that's the case, an engineer designs a computer model of the object. Then, guided by this model, a 3-d printer produces a physical model out of plastic, building the miniature replica from the bottom up one thin layer at a time. These mountaintop castles in portugal are the finishing touch on this model that's set to go on display at the local tourist center. Solid terrain models are a creative and valuable tool for educating people young and old. By translating complicated technical data into a unique and scientifically sound visual aid, a solid terrain model delivers a fascinating bird's-eye view from the ground. Stucco is one of the oldest construction materials on the planet. The earliest formulations date back to ancient greece and mayan mexico. Stucco has stuck around, and as an exterior siding, it's come a long way. Modern stucco is more attractive and offers better protection. Whether cement- or acrylic-based, stucco always starts out as a sticky paste, and that's the great thing about stucco. In this wet and gooey form, it can be worked as it's applied to the exterior of a building to achieve a variety of textures. It hardens to provide a tough exterior that shields the building against the elements. To mass-produce cement stucco, they start with tons of silica sand. They unload it into a conveyor and elevator system, which delivers the sand to silos for storage until needed. They select sand with various grades of coarseness for different stucco finishes. They mix it with cement, lime, and other ingredients to create the stucco base. A technician demonstrates how the ingredients come together using this research lab mixer. She blends all the ingredients dry, achieving a consistency that's similar to cake mix from a box. Cement stucco is sold in dry form. Water will be added to liquefy the ingredients on the job site. In this demonstration, she also adds pigment. With the stucco pre-colored, there's no need to paint the building. To mass-produce cement stucco, they use this mega-mixer. The operator adds three or four different pigments to create a custom color in the dry stucco batch. Large paddle blades spiral vigorously. Usually, this is a closed operation, but they've opened it up for our camera. After three minutes of mixing, the dry stucco mix is ready for scrutiny. An employee takes a sample and sends it to the quality control lab for evaluation. At the lab, the technician weighs the stucco mixture and adds water. He keeps an eye on the scale to ensure that the amounts are proportionate. He mixes them and visually checks to confirm that the pigment and raw materials are well dispersed. Acrylic stucco, on the other hand, calls for an entirely different recipe. They use calcium carbonate instead of silica send and acrylic as a binder instead of cement. They mix it with water and sell it wet in a bucket instead of dry. To color it, they use a computerized tint machine, similar to what you find in a paint store. They load the machine with liquid pigments and enter a color formula into the computer. It mixes the pigments to produce the exact color. And it releases the precise amount needed. They blend the color into the acrylic stucco, and the batch ends up looking like blue mud. It's now ready to apply to a home. No prep required. They also sell acrylic stucco with no color at all. It's called tint base. The pigments will be added on the job site, where they can be adjusted if needed. An airtight seal keeps the stucco in its viscous state. Acrylic stucco dries quickly, like paint, while cement stucco takes 28 days to totally cure into a more durable finish. Over on the cement stucco line, a rotating machine handles all the packaging. A suctioning device pulls a paper bag into position under a spout, which then fills it up. It takes just 8 seconds to fill a 90-pound bag. That works out to over 1,300 bags per hour, enough material for 30 houses. The machine transfers the bag to the conveyor belt. This stucco is now ready to provide a strong finish to building projects. Applied to a building's exterior, stucco can be textured to suit the homeowner's taste, and it will harden to provide the building with a tough skin. That's why stucco continues to be part of the urban landscape. An industrial roll-up door opens and closes at least three times as fast as your average residential garage door. That means machines and products can be moved in and out quickly. These heavy-duty rubber doors are also engineered for a good seal, so they're weathertight. In many workplaces, doors are always opening and closing. A high-speed roll-up door is designed for heavy traffic. Coal mines, parking garages, and large food freezer rooms are just a few of the places you will find them in action. They start with rubber panels. Their number and size depends on the width of the door being manufactured. Workers brush high-strength epoxy onto the edges to bind the panels together. The epoxy will take a couple of hours to cure, so there's time to smooth out the air bubbles by applying pressure to the seams with a heavy roller. After the epoxy cures, they map out areas with masking tape to contain glue for the application of extruded rubber strips. The horizontal one is a stiffener, and the vertical strips at the sides are wind blocks. They'll secure the curtain to the building even in bad weather. The employee also applies synthetic fabric to both sides to prevent wear. He adds reflective yellow strips to the front and back to make the black rubber door visible at night. A machine now drills holes in a steel tube. This tube is the header that the rubber curtain will be rolled up on to. The holes will be used to attach the curtain to it. He tack-welds axles onto both ends of the tube. The axles will be attached to mounting plates, so these are critical welds. He measures the axles to confirm that the assembly is level and won't wobble. Satisfied, he welds them permanently to the steel tube. Next, he assembles and welds the side frame for the rubber curtain. He assembles a hinge cover to the front of the frame, creating a compartment for the curtain that can be opened when needed. Then it's on to the paint booth. Here, an employee primes the frame components to protect them from rust and then gives them a coat of paint. A worker assembles the bottom beam now. He bolts an aluminum track for the rubber edging to a heavy steel frame. He screws the box for the wireless transmitter that opens and closes the door to the beam. Two workers now pull the rubber edging through the aluminum track. The edging is equipped with an electric safety wire to detect movement and abort a door closing. This will keep the door from hitting anyone who walks under it. It's now time to pull everything together. The team screws the rubber curtain to the steel tube, making use of those pre-drilled holes. They move down and position the bottom beam on the curtain. They attach it to the curtain with numerous nuts and bolts. They roll up the rubber curtain to prepare for assembly to the mounting brackets. With the attachments, the curtain now weighs over 1,100 pounds. A crane transfers it to the end mounting plates and holds it steady while workers slide the end brackets onto the axles. They build a steel support structure around the brackets and the rolled-up curtain. They attach the motor to one of the axles. This roll-up door is now ready for delivery. Two days in the making, it's ready for whatever comes its way.