One-hundred-and-thirty years back, Thomas Edison completed the initial successful sustained test of the incandescent bulb. With some incremental improvements in the process, Edison’s basic technology has lit the entire world ever since. This is about to change. We are on the cusp of a semiconductor-based lighting revolution that can ultimately replace Edison’s bulbs with a much more energy-efficient lighting solution. Solid state LED lighting will ultimately replace almost all the countless huge amounts of incandescent and fluorescent lights in use around the world today. Actually, as a step along this path, The President last June unveiled new, stricter lighting standards which will support the phasing out of incandescent bulbs (which already are banned in parts of Europe).
To understand precisely how revolutionary Mini power supply are in addition to why these are still expensive, it is instructive to look at how they are manufactured and also to compare this to the output of incandescent light bulbs. This post explores how incandescent lights are created then contrasts that process with a description from the typical manufacturing process for LED bulbs.
So, let’s start with taking a look at how traditional incandescent light bulbs are manufactured. You will see that this can be a classic illustration of an automated industrial process refined in spanning a century of expertise.
While individual incandescent light types differ in dimensions and wattage, them all possess 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 usually made of nickel-iron wire. This wire is dipped in to a borax answer to have the wire more adherent to glass. The bulb itself is made from glass and possesses a blend of gases, usually argon and nitrogen, which raise the life of the filament. Air is pumped out of the bulb and substituted with the gases. A standardized base supports the entire assembly set up. The base is called the “Edison screw base.” Aluminum is utilized on the outside and glass employed to insulate the inside of the base.
Originally created by hand, light manufacturing has become almost entirely automated. First, the filament is manufactured using a process known as drawing, in which tungsten is combined with a binder material and pulled via a die (a shaped orifice) in to a fine wire. Next, the wire is wound around a metal bar called a mandrel so that you can 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 will be dissolved in acid.
Second, the coiled filament is linked to the lead-in wires. The lead-in wires have hooks at their ends that are either pressed within the end in 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 within the conveyor belt into molds, creating the casings. A ribbon machine moving at top speed can produce a lot more than 50,000 bulbs each hour. After the casings are blown, these are cooled then cut off of the ribbon machine. Next, the within the bulb is coated with silica to get rid of the glare caused by a glowing, uncovered filament. The label and wattage are then stamped on the outside top of each casing.
Fourth, the base of the bulb is also constructed using molds. It is made with indentations in the form of a screw so that it can certainly fit into the socket of the light fixture.
Fifth, when the filament, base, and bulb are made, they may be fitted together by machines. First, the filament is mounted towards the stem assembly, with its ends clamped for the two lead-in wires. Next, the environment inside the bulb is evacuated, and also the casing is filled with the argon and nitrogen mixture.
Finally, the base and also the bulb are sealed. The base slides onto the end of the glass bulb to ensure that no other material is necessary to keep these together. Instead, their conforming shapes enable the two pieces to become held together snugly, with the lead-in wires touching the aluminum base to make sure proper electrical contact. After testing, bulbs are positioned in their packages and shipped to consumers.
Bulbs are tested for 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 measure of how long the bulb will last under normal conditions. Tests are performed whatsoever manufacturing plants in addition to at some independent testing facilities. The typical lifetime of the typical household bulb is 750 to one thousand hours, based on wattage.
LED light bulbs are built around solid-state semiconductor devices, so the manufacturing process most closely resembles that utilized to make electronic products like PC mother boards.
A light-emitting diode (LED) is actually 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 replace miniature light bulbs. Inside the last decade, advances within the technology finally boosted light output high enough for LEDs to begin with to seriously contest with incandescent and fluorescent lights. As with many technologies, as the cost of production falls each successive LED generation also improves in light quality, output per watt, and heat management.
The computer market is well suitable for manufacture LED lighting. The procedure isn’t a whole lot distinct from creating a computer motherboard. The businesses making the LEDs are generally not within the lighting business, or it really is a minor part of their business. They are usually semiconductor houses that are happy cranking out their product, which is the reason prices on high-output LEDs has fallen a great deal in the last fifteen years.
LED bulbs are expensive in part since it takes several LEDs to obtain wide-area illumination as opposed to 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 includes four essential components: an LED circuit board, a heatsink, an electric power supply, as well as a shell. The lights begin as bare printed circuit boards (PCB) and high luminance LED elements arrive from separate factories which focus on making those components. LED elements themselves create some heat, therefore the PCB used in lights is special. Instead of the standard non-conductive sandwich of epoxy and fiberglass, the circuit board is presented over a thin sheet of aluminum which acts as a heatsink.
The aluminum PCB used in LED lighting is coated with a non-conducting material and conductive copper trace lines to form the circuit board. Solder paste will be applied in the right places and after that Surface Mount Technology (SMT) machines put the tiny LED elements, driver ICs, and other components on the board at ultra high speeds.
The round shape of a regular light means that most LED printed circuit boards are circular, so for ease of handling a lot 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 in the end the individual cupcakes are snapped free from the tray.
Let’s check out the manufacturing steps for a typical LED bulb designed to replace a standard incandescent bulb having an Edison Screw. You will find that it is a totally different process through the highly automated processes used to manufacture our familiar incandescent bulbs. And, despite whatever you might imagine, folks are still greatly a necessary part of manufacturing process, and not simply for testing and Quality Assurance either.
Once the larger sheets of LED circuit boards have passed via a solder reflow oven (a hot air furnace that melts the solder paste), they are broken up to the individual small circuit boards and power wires manually soldered on.
The small power source housed in the body of the light goes through an identical process, or may be delivered complete from another factory. Either way, the manufacturing steps are identical; first the PCB passes through SMT lines, it goes to a manual dual in-line package (DIP) assembly line when a long row of factory workers add one component at a time. DIP refers back to the two parallel rows of leads projecting from the sides of the package. DIP components include all integrated chips and chip sockets.
While LED lights burn several times over incandescent or CFLs and require less than half the vitality, they need some form of passive heatsink keep the high-power LEDs from overheating. The LED circuit board, which is made of 1.6-2mm thick aluminum, will conduct the heat from your dozen approximately LED elements to the metal heatsink frame and thus keep temperatures in balance. Aluminum-backed PCBs are sometimes called “metal core printed circuit boards,” despite the fact that manufactured from a conductive material the white coating is electrically isolating. The aluminum PCB is screwed in place inside the heatsink which forms the low half of the LED light bulb.
After this, the energy connector board is fixed in position with adhesive. The small power source converts 120/240V AC mains power to a lower voltage (12V or 24V), it fits in 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 using the metal heatsink and LED circuit board. Ventilation holes are included to allow hot air to avoid. 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 working properly and burned in for thirty minutes. There is also a high-voltage leakage and breakdown test and power consumption and power factor test. Samples through the production run are tested for high-voltage leaks, power consumption, and power factor (efficiency).
The finished bulbs go through one final crimping step because the metal socket base is crimped in position, are bar-coded and identified with lot numbers. External safety labels are applied as well as the bulb is inked with information, like brand and model number. Finally, all that’s left would be to fix on the clear plastic LED cover that is glued in position.
After having a final check to make certain all of the different areas of the LED light are tight, then its packed into individual boxes, and bulbs are shipped out.
So, for those who have wondered why LED light bulbs are really expensive today, this explanation of how they are manufactured and just how that compares to the manufacture of traditional light bulbs should help. However, it jrlbac reveals why the price will fall pretty dramatically on the next couple of years. Just as the expense of manufacturing other semiconductor-based products has fallen dramatically due to standardization, automation along with other key steps across the manufacturing learning curve, exactly the same inexorable forces will drive down the costs of LED light production.