One-hundred-and-thirty years back, Thomas Edison completed the very first successful sustained test of the incandescent light bulb. With a few incremental improvements in the process, Edison’s basic technology has lit the entire world ever since. This is going to change. We are on the cusp of a semiconductor-based lighting revolution that will ultimately replace Edison’s bulbs with a much more energy-efficient lighting solution. Solid state LED lighting will eventually replace almost all of the countless huge amounts of incandescent and fluorescent lights in use all over the world today. Actually, as a step along this path, President Obama last June introduced new, stricter lighting standards which will support the phasing out of incandescent bulbs (which already are banned in parts of Europe).
To comprehend precisely how revolutionary Mini power supply are as well as why they may be still expensive, it is instructive to look at the way they are manufactured as well as compare this to the creation of incandescent light bulbs. This short article explores how incandescent lights are produced and then contrasts that process having a description from the typical manufacturing process for LED light bulbs.
So, let’s start with considering how traditional incandescent bulbs are produced. You will notice that it is a classic demonstration of a computerized industrial process refined in over a century of expertise.
While individual incandescent light bulb types differ in size and wattage, all of them hold the three basic parts: the filament, the bulb, and the base. The filament is made from tungsten. While very fragile, tungsten filaments can withstand temperatures of 4,500 degrees Fahrenheit and above. The connecting or lead-in wires are typically made from nickel-iron wire. This wire is dipped right into a borax solution to make the wire more adherent to glass. The bulb itself consists of glass and has a combination of gases, usually argon and nitrogen, which raise the lifetime of the filament. Air is pumped out of the bulb and substituted for the gases. A standardized base holds the entire assembly in position. The base is known as the “Edison screw base.” Aluminum is utilized on the outside and glass employed to insulate the within the base.
Originally made by hand, bulb manufacturing is currently almost entirely automated. First, the filament is manufactured employing a process known as drawing, where tungsten is blended with a binder material and pulled through a die (a shaped orifice) right into a fine wire. Next, the wire is wound around metallic bar called a mandrel so that you can mold it into its proper coiled shape, and then its heated in a process known as annealing, softening the wire and makes its structure more uniform. The mandrel is then dissolved in acid.
Second, the coiled filament is attached to the lead-in wires. The lead-in wires have hooks at their ends which are either pressed on the end in the filament or, in larger bulbs, spot-welded.
Third, the glass bulbs or casings are produced using a ribbon machine. After heating in a furnace, a continuous ribbon of glass moves along a conveyor belt. Precisely aligned air nozzles blow the glass through holes within the conveyor belt into molds, creating the casings. A ribbon machine moving at top speed can produce greater than 50,000 bulbs per hour. Following the casings are blown, they are cooled then cut from the ribbon machine. Next, the inside the bulb is coated with silica to eliminate the glare caused by a glowing, uncovered filament. The label and wattage are then stamped to the outside top of each casing.
Fourth, the lower bulb can also be constructed using molds. It is made with indentations inside the shape of a screw so it can easily match the socket of the light fixture.
Fifth, after the filament, base, and bulb are produced, they may be fitted together by machines. First, the filament is mounted to the stem assembly, with its ends clamped for the two lead-in wires. Next, air in the bulb is evacuated, and also the casing is full of the argon and nitrogen mixture.
Finally, the base as well as the bulb are sealed. The base slides to the end of the glass bulb to ensure that not one other material is necessary to have them together. Instead, their conforming shapes enable the two pieces to get held together snugly, using the lead-in wires touching the aluminum base to ensure proper electrical contact. After testing, bulbs are positioned inside their packages and shipped to consumers.
Bulbs are tested for both lamp life and strength. To be able to provide quick results, selected bulbs are screwed into life test racks and lit at levels far exceeding normal. This supplies a precise way of measuring just how long the bulb will last under normal conditions. Testing is performed whatsoever manufacturing plants in addition to at some independent testing facilities. The typical lifetime of the typical household bulb is 750 to 1,000 hours, based on wattage.
LED light bulbs are built around solid-state semiconductor devices, and so the manufacturing process most closely resembles that employed to make electronic items like PC mother boards.
An easy-emitting diode (LED) is really a solid state electrical circuit that generates light by the movement of electrons in a semiconductor material. LED technology has been around since the late 1960s, but for the first 40 years LEDs were primarily utilized in electronics devices to change miniature light bulbs. Within the last decade, advances in the technology finally boosted light output high enough for LEDs to start to seriously contest with incandescent and fluorescent lights. As with many technologies, as the price of production falls each successive LED generation also improves in light quality, output per watt, and heat management.
Your computer sector is well fitted to manufacture LED lighting. The process isn’t a great deal different than creating a computer motherboard. The firms making the LEDs themselves are generally not inside the lighting business, or this is a minor element of their business. They tend to be semiconductor houses that are happy cranking out their product, which explains why prices on high-output LEDs has fallen a great deal within the last fifteen years.
LED bulbs themselves are expensive partly because it takes several LEDs to have wide-area illumination instead of a narrow beam, and also the assembly cost enhances the overall price. Furthermore, assemblies comprising arrays of LEDs create more opportunities for product defects.
An LED light contains four essential components: an LED circuit board, a heatsink, a power supply, as well as a shell. The lights begin as bare printed circuit boards (PCB) and luminance LED elements arrive from separate factories which focus on making those components. LED elements themselves create a little bit of heat, therefore the PCB utilized in lighting fixtures is special. Instead of the standard non-conductive sandwich of epoxy and fiberglass, the circuit board is organized over a thin sheet of aluminum which behaves as a heatsink.
The aluminum PCB utilized in LED lights are coated with a non-conducting material and conductive copper trace lines to make the circuit board. Solder paste is then applied within the right places and after that Surface Mount Technology (SMT) machines position the tiny LED elements, driver ICs, and other components to the board at ultra high speeds.
The round shape of a traditional bulb means that most LED printed circuit boards are circular, so for easy handling several of the smaller circular PCBs are combined into one larger rectangular PCB that automated SMT machinery are designed for. Consider it just like a cupcake tray moving from a single machine to the next along a conveyor belt, then at the conclusion the person cupcakes are snapped clear of the tray.
Let’s have a look at the manufacturing steps to get a typical LED light meant to replace a typical incandescent bulb having an Edison Screw. You will notice that it really is a completely different process from the highly automated processes employed to manufacture our familiar incandescent bulbs. And, despite whatever you might imagine, individuals are still very much an essential element of manufacturing process, and not simply for testing and Quality Assurance either.
After the larger sheets of LED circuit boards have passed through a solder reflow oven (a heat furnace that melts the solder paste), these are broken up into the individual small circuit boards and power wires manually soldered on.
The tiny power source housed within the body in the light goes through a similar process, or might be delivered complete from another factory. In any case, the manufacturing steps are identical; first the PCB passes through SMT lines, it goes toward a manual dual in-line package (DIP) assembly line in which a long row of factory workers add one component at a time. DIP means the two parallel rows of leads projecting from your sides from the package. DIP components include all integrated chips and chip sockets.
While Leds burn several times more than incandescent or CFLs and require less than half the power, they want some form of passive heatsink maintain the high-power LEDs from overheating. The LED circuit board, which is manufactured out of 1.6-2mm thick aluminum, will conduct the heat through the dozen roughly LED elements to the metal heatsink frame and thus keep temperatures under control. Aluminum-backed PCBs are sometimes called “metal core printed circuit boards,” even though made of a conductive material the white coating is electrically isolating. The aluminum PCB is screwed set up in the heatsink which forms the low 50 % of the LED bulb.
After this, the energy connector board is fixed in position with adhesive. The tiny power source converts 120/240V AC mains power to a lower voltage (12V or 24V), it suits the cavity behind the aluminum PCB.
Shell assembly contains locking the shell in position with screws. A plastic shell covers the energy supply and connects with all the metal heatsink and LED circuit board. Ventilation holes are included to enable heat to avoid. Wiring assembly for plug socket requires soldering wires for the bulb socket. Then shell is attached.
Next, the completed LED light is delivered to burn-in testing and quality control. The burn-in test typically lasts for thirty minutes. The completed LED light bulb will then be powered up to determine if it is actually functioning properly and burned set for 30 minutes. There is also a high-voltage leakage and breakdown test and power consumption and power factor test. Samples from your production run are tested for high-voltage leaks, power consumption, and power factor (efficiency).
The finished bulbs move through the last crimping step since the metal socket base is crimped set up, are bar-coded and identified with lot numbers. External safety labels are applied as well as the bulb is inked with information, like logo and model number. Finally, all that’s left would be to fix on the clear plastic LED cover which can be glued in place.
After a final check to make sure all the different parts of the LED light are tight, then it is packed into individual boxes, and bulbs are shipped out.
So, in case you have wondered why LED light bulbs are so expensive today, this explanation of how they are manufactured and exactly how that comes even close to the output of traditional bulbs should help. However, it jrlbac reveals why the cost will fall pretty dramatically over the next few years. Just as the expense of manufacturing other semiconductor-based products has fallen dramatically because of standardization, automation along with other key steps across the manufacturing learning curve, exactly the same inexorable forces will drive along the costs of LED light bulb production.