One-hundred-and-thirty years back, Thomas Edison completed the first successful sustained test of the incandescent light bulb. With some incremental improvements along the way, 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 the countless vast amounts of incandescent and fluorescent lights in use around the globe today. In fact, as a step along this path, The President last June unveiled new, stricter lighting standards that can support the phasing out of incandescent bulbs (which already are banned in parts of Europe).
To understand precisely how revolutionary Strip power supply are in addition to why they may be still expensive, it is actually instructive to consider how they are made and to compare this to the creation of incandescent lights. This article explores how incandescent lights are produced and after that contrasts that process having a description from the typical manufacturing process for LED bulbs.
So, let’s begin by examining how traditional incandescent bulbs are produced. You will find that this is a classic demonstration of a computerized industrial process refined in more than a century of experience.
While individual incandescent bulb types differ in dimensions and wattage, every one of them have the three basic parts: the filament, the bulb, and also 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 generally manufactured from nickel-iron wire. This wire is dipped in to a borax means to fix have the wire more adherent to glass. The bulb itself is made from glass and possesses a combination of gases, usually argon and nitrogen, which increase the life of the filament. Air is pumped from the bulb and substituted for the gases. A standardized base supports the entire assembly in place. The base is known as the “Edison screw base.” Aluminum can be used on the outside and glass employed to insulate the inside the base.
Originally created by hand, light bulb manufacturing has become almost entirely automated. First, the filament is manufactured using a process called drawing, by which tungsten is combined with a binder material and pulled through a die (a shaped orifice) into a fine wire. Next, the wire is wound around metallic bar known as a mandrel in order to 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 will be dissolved in acid.
Second, the coiled filament is connected to the lead-in wires. The lead-in wires have hooks at their ends which are either pressed within the end from the filament or, in larger bulbs, spot-welded.
Third, the glass bulbs or casings are made 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 each hour. After the casings are blown, these 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 surface of each casing.
Fourth, the base of the bulb is additionally constructed using molds. It is produced with indentations in the shape of a screw to ensure that it can easily fit into the socket of a light fixture.
Fifth, when the filament, base, and bulb are produced, they may be fitted together by machines. First, the filament is mounted towards the stem assembly, with its ends clamped towards the two lead-in wires. Next, the air within the bulb is evacuated, and the casing is stuffed with the argon and nitrogen mixture.
Finally, the base and the bulb are sealed. The base slides onto the end of the glass bulb in a way that not one other material is necessary to keep them together. Instead, their conforming shapes permit the two pieces to get held together snugly, using the lead-in wires touching the aluminum base to make sure proper electrical contact. After testing, bulbs are put within their packages and shipped to consumers.
Light bulbs are tested for both lamp life and strength. So that you can provide quick results, selected bulbs are screwed into life test racks and lit at levels far exceeding normal. This gives an exact way of measuring how much time the bulb may last under normal conditions. Testing is performed whatsoever manufacturing plants as well as at some independent testing facilities. The normal lifetime of the standard household bulb is 750 to one thousand hours, depending on wattage.
LED lights are built around solid-state semiconductor devices, therefore the manufacturing process most closely resembles that employed to make electronic items like PC mother boards.
An easy-emitting diode (LED) is actually 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, as well as the first 40 years LEDs were primarily utilized in electronics devices to replace miniature bulbs. Within the last decade, advances in the technology finally boosted light output sufficient for LEDs to begin with to seriously contest with incandescent and fluorescent light bulbs. Similar to many technologies, as the price of production falls each successive LED generation also improves in light quality, output per watt, and heat management.
The computer sector is well suited to manufacture LED lighting. This process isn’t a great deal diverse from building a computer motherboard. The firms making the LEDs are generally not in the lighting business, or it is a minor a part 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 a lot in the last 15 years.
LED bulbs are expensive to some extent because it takes a number of LEDs to have wide-area illumination rather than a narrow beam, and also the assembly cost enhances 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, an electric power supply, and 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, so the PCB used in lighting fixtures is special. Instead of the standard non-conductive sandwich of epoxy and fiberglass, the circuit board is presented on a thin sheet of aluminum which works as a heatsink.
The aluminum PCB used in LED lights are coated having a non-conducting material and conductive copper trace lines to create the circuit board. Solder paste will then be applied inside the right places and after that Surface Mount Technology (SMT) machines place the tiny LED elements, driver ICs, as well as other components on the board at ultra high speeds.
The round form of a traditional light bulb means that most LED printed circuit boards are circular, so for easy handling a lot of the smaller circular PCBs are combined into one larger rectangular PCB that automated SMT machinery can handle. Consider it like a cupcake tray moving in one machine to the next along a conveyor belt, then in the end the patient cupcakes are snapped clear of the tray.
Let’s have a look at the manufacturing steps to get a typical LED light bulb meant to replace a regular incandescent bulb having an Edison Screw. You will find that it is a very different process through the highly automated processes utilized to manufacture our familiar incandescent bulbs. And, despite everything you might imagine, folks are still very much an essential part of manufacturing process, and not merely for testing and Quality Assurance either.
Once the larger sheets of LED circuit boards have passed by way of a solder reflow oven (a hot air furnace that melts the solder paste), they are broken up in to the individual small circuit boards and power wires manually soldered on.
The little power supply housed within the body in the bulb goes through an identical process, or might 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 where a long row of factory workers add one component at the same time. DIP means the two parallel rows of leads projecting from the sides in the package. DIP components include all integrated chips and chip sockets.
While Leds burn repeatedly more than incandescent or CFLs and require less than half the vitality, they need some kind of passive heatsink maintain the high-power LEDs from overheating. The LED circuit board, which is made from 1.6-2mm thick aluminum, will conduct the heat through the dozen approximately LED elements towards the metal heatsink frame and thus keep temperatures in balance. Aluminum-backed PCBs are occasionally 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 in the heatsink which forms the reduced 50 % of the LED light bulb.
After this, the energy connector board is fixed in place with adhesive. The small power source converts 120/240V AC mains capacity to a reduced voltage (12V or 24V), it suits the cavity behind the aluminum PCB.
Shell assembly includes locking the shell in place with screws. A plastic shell covers the power supply and connects with all the metal heatsink and LED circuit board. Ventilation holes are included to enable hot air to flee. Wiring assembly for plug socket requires soldering wires towards 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 is then powered up to determine if it really is functioning properly and burned in for thirty minutes. Additionally there is a high-voltage leakage and breakdown test and power consumption and power factor test. Samples from your production run are tested for top-voltage leaks, power consumption, and power factor (efficiency).
The finished bulbs pass through one final 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, such as brand name and model number. Finally, all that’s left would be to fix on the clear plastic LED cover that is glued in place.
After having a final check to ensure all the different elements of the LED light are tight, then it is packed into individual boxes, and bulbs are shipped out.
So, if you have wondered why LED bulbs are so expensive today, this explanation of methods they are manufactured and just how that compares to the manufacture of traditional bulbs should help. However, it jrlbac reveals why the fee will fall pretty dramatically within the next several years. Just like the price of manufacturing other semiconductor-based products has fallen dramatically due to standardization, automation as well as other key steps across the manufacturing learning curve, exactly the same inexorable forces will drive along the costs of LED bulb production.