One-hundred-and-thirty years back, Thomas Edison completed the first successful sustained test of the incandescent light bulb. With many incremental improvements along the way, Edison’s basic technology has lit the 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 a lot more energy-efficient lighting solution. Solid state LED lighting will ultimately replace almost all the hundreds of billions of incandescent and fluorescent lights in use around the globe today. In fact, as being a step along this path, President Obama last June unveiled new, stricter lighting standards that will support the phasing out of incandescent bulbs (which already are banned in parts of Europe).
To comprehend precisely how revolutionary led power supply module are in addition to why they may be still expensive, it is instructive to check out how they are manufactured and to compare this to the output of incandescent lights. This article explores how incandescent light bulbs are created and after that contrasts that process having a description of the typical manufacturing process for LED bulbs.
So, let’s start by examining how traditional incandescent bulbs are produced. You will find that this is a classic demonstration of a computerized industrial process refined in spanning a century of experience.
While individual incandescent light types differ in dimensions and wattage, every one of them possess 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 usually manufactured from nickel-iron wire. This wire is dipped into a borax means to fix have the wire more adherent to glass. The bulb itself is made of glass and possesses a combination of gases, usually argon and nitrogen, which boost 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 referred to as the “Edison screw base.” Aluminum is utilized on the outside and glass used to insulate the inside the base.
Originally produced by hand, light bulb manufacturing has become almost entirely automated. First, the filament is manufactured employing a process called drawing, where tungsten is blended with a binder material and pulled by way of a die (a shaped orifice) into a fine wire. Next, the wire is wound around a metal bar called a mandrel to be able to mold it into its proper coiled shape, and then it is heated in a process called annealing, softening the wire and makes its structure more uniform. The mandrel is then dissolved in acid.
Second, the coiled filament is connected to the lead-in wires. The lead-in wires have hooks at their ends that are either pressed over the end from the filament or, in larger bulbs, spot-welded.
Third, the glass bulbs or casings are produced employing 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 inside the conveyor belt into molds, creating the casings. A ribbon machine moving at top speed can produce more than 50,000 bulbs per hour. Following the casings are blown, they are cooled and after that cut off the ribbon machine. Next, the inside the bulb is coated with silica to eliminate the glare the consequence of glowing, uncovered filament. The label and wattage are then stamped on the outside surface of each casing.
Fourth, the bottom of the bulb is additionally constructed using molds. It is produced with indentations in the model of a screw so that it can simply fit into the socket of the light fixture.
Fifth, after the filament, base, and bulb are created, they are fitted together by machines. First, the filament is mounted to the stem assembly, featuring its ends clamped for the two lead-in wires. Next, the air within the bulb is evacuated, and the casing is filled with the argon and nitrogen mixture.
Finally, the base and the bulb are sealed. The base slides onto the end of the glass bulb to ensure that hardly any other material is necessary to keep these together. Instead, their conforming shapes allow the two pieces to become held together snugly, using the lead-in wires touching the aluminum base to make certain proper electrical contact. After testing, bulbs are put in 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 provides a precise way of measuring just how long the bulb may last under normal conditions. Tests are performed at all manufacturing plants along with at some independent testing facilities. The normal life of the normal household bulb is 750 to one thousand hours, based on wattage.
LED lights are designed around solid-state semiconductor devices, and so the manufacturing process most closely resembles that used to make electronic products like PC mother boards.
An easy-emitting diode (LED) is really a solid state electrical circuit that generates light through the movement of electrons in a semiconductor material. LED technology has been available since the late 1960s, but also for the first 40 years LEDs were primarily used in electronics devices to change miniature lights. Inside the last decade, advances inside the technology finally boosted light output sufficient for LEDs to begin to seriously compete with incandescent and fluorescent light bulbs. Similar to many technologies, as the expense 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 procedure isn’t a lot diverse from making a computer motherboard. The businesses making the LEDs are generally not in the lighting business, or it is a minor element of their business. They are usually semiconductor houses that are happy cranking out their product, which is why prices on high-output LEDs has fallen so much within the last 20 years.
LED bulbs are expensive partly because it takes a number of LEDs to get wide-area illumination instead of a narrow beam, and the assembly cost adds to the overall price. In addition, assemblies consisting of arrays of LEDs create more opportunities for product defects.
An LED light consists of four essential components: an LED circuit board, a heatsink, a power supply, and a shell. The lights start off as bare printed circuit boards (PCB) and luminance LED elements arrive from separate factories which specialize in making those components. LED elements themselves create a bit of heat, and so the PCB used in lights is special. Rather than the standard non-conductive sandwich of epoxy and fiberglass, the circuit board is presented over a thin sheet of aluminum which works as a heatsink.
The aluminum PCB utilized in LED lighting is coated using a non-conducting material and conductive copper trace lines to make the circuit board. Solder paste will then be applied in the right places and after that Surface Mount Technology (SMT) machines place the tiny LED elements, driver ICs, along with other components to the board at ultra high speeds.
The round form of a traditional bulb signifies that most LED printed circuit boards are circular, so for ease of handling some of the smaller circular PCBs are combined into one larger rectangular PCB that automated SMT machinery are designed for. Think about it such as a cupcake tray moving from one machine to the next along a conveyor belt, then in the end the individual cupcakes are snapped free from the tray.
Let’s have a look at the manufacturing steps for a typical LED light meant to replace a standard incandescent bulb having an Edison Screw. You will notice that this is a completely different process from your highly automated processes used to manufacture our familiar incandescent bulbs. And, despite what you might imagine, folks are still significantly a necessary a part of manufacturing process, and not just for testing and Quality Assurance either.
When the larger sheets of LED circuit boards have passed via a solder reflow oven (a heat furnace that melts the solder paste), they are separated to the individual small circuit boards and power wires manually soldered on.
The tiny power supply housed in your body in the bulb undergoes a similar process, or could be delivered complete from another factory. In either case, the manufacturing steps are similar; first the PCB passes through SMT lines, it goes to a manual dual in-line package (DIP) assembly line in which a long row of factory workers add one component at the same time. DIP refers to the two parallel rows of leads projecting from the sides from the package. DIP components include all integrated chips and chip sockets.
While LED lights burn many times over incandescent or CFLs and require less than half the energy, they want some kind of passive heatsink keep your high-power LEDs from overheating. The LED circuit board, which is made of 1.6-2mm thick aluminum, will conduct the temperature from the dozen roughly LED elements towards the metal heatsink frame and thus keep temperatures under control. Aluminum-backed PCBs are often called “metal core printed circuit boards,” even though made from a conductive material the white coating is electrically isolating. The aluminum PCB is screwed in place inside the heatsink which forms the reduced half of the LED light.
Following this, the ability connector board is fixed in place with adhesive. The small power source converts 120/240V AC mains power to a reduced voltage (12V or 24V), it fits in the cavity behind the aluminum PCB.
Shell assembly includes locking the shell set up 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 flee. Wiring assembly for plug socket requires soldering wires to 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 can last for half an hour. The completed LED light bulb is then powered up to determine if it is actually working properly and burned set for half an hour. There is also a high-voltage leakage and breakdown test and power consumption and power factor test. Samples from the production run are tested for high-voltage leaks, power consumption, and power factor (efficiency).
The finished bulbs go through the last crimping step since the metal socket base is crimped in place, are bar-coded and identified with lot numbers. External safety labels are applied and also the bulb is inked with information, such as logo and model number. Finally, all that’s left is to fix on the clear plastic LED cover that is glued set up.
Following a final check to make sure all the various 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 lights are extremely expensive today, this explanation of how they may be manufactured and how that compares to the output of traditional lights should help. However, it jrlbac reveals why the fee will fall pretty dramatically within the next couple of years. Just as the cost of manufacturing other semiconductor-based products has fallen dramatically because of standardization, automation along with other key steps over the manufacturing learning curve, exactly the same inexorable forces will drive along the costs of LED light production.