One-hundred-and-thirty years back, Thomas Edison completed the initial successful sustained test of the incandescent light bulb. With a few incremental improvements in the process, Edison’s basic technology has lit the 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 a lot more energy-efficient lighting solution. Solid state LED lighting will eventually replace almost all the numerous vast amounts of incandescent and fluorescent lights in use all over the world today. In reality, 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 LED power china are as well as why these are still expensive, it is actually instructive to check out the way they are manufactured as well as compare this for the manufacture of incandescent bulbs. This post explores how incandescent light bulbs are made and after that contrasts that process having a description of the typical manufacturing process for LED light bulbs.
So, let’s start by taking a look at how traditional incandescent lights are manufactured. You will see that this is a classic example of an automated industrial process refined in spanning a century of experience.
While individual incandescent bulb types differ in dimensions and wattage, every one of them possess the three basic parts: the filament, the bulb, and also the base. The filament consists of 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 in to a borax solution to make the wire more adherent to glass. The bulb itself is made from glass and contains a combination of gases, usually argon and nitrogen, which boost the lifetime of the filament. Air is pumped out from the bulb and replaced with the gases. A standardized base holds the entire assembly set up. The base is referred to as the “Edison screw base.” Aluminum is utilized on the outside and glass used to insulate the inside of the base.
Originally made by hand, light manufacturing is currently almost entirely automated. First, the filament is manufactured employing a process known as drawing, by which tungsten is mixed with a binder material and pulled by way of a die (a shaped orifice) right into a fine wire. Next, the wire is wound around metallic bar called a mandrel to be able 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 linked to the lead-in wires. The lead-in wires have hooks at their ends which are either pressed over the end from the filament or, in larger bulbs, spot-welded.
Third, the glass bulbs or casings are made utilizing 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 in the conveyor belt into molds, creating the casings. A ribbon machine moving at top speed can produce more than 50,000 bulbs per hour. After the casings are blown, they are cooled and then cut from the ribbon machine. Next, the within the bulb is coated with silica to remove the glare the consequence of glowing, uncovered filament. The label and wattage are then stamped onto the outside top of each casing.
Fourth, the base of the bulb is also constructed using molds. It is made with indentations in the shape of a screw to ensure that it can simply match the socket of any light fixture.
Fifth, once the filament, base, and bulb are created, they are fitted together by machines. First, the filament is mounted for the stem assembly, using its ends clamped towards the two lead-in wires. Next, air inside 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 in the glass bulb in a way that hardly any other material is needed to keep them together. Instead, their conforming shapes permit the two pieces to become held together snugly, with the lead-in wires touching the aluminum base to ensure proper electrical contact. After testing, bulbs are put in their packages and shipped to consumers.
Light bulbs are tested both for lamp life and strength. In order to 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 long the bulb may last under normal conditions. Tests are performed in any way manufacturing plants along with at some independent testing facilities. The normal life of the standard household bulb is 750 to one thousand hours, depending on wattage.
LED bulbs are made around solid-state semiconductor devices, therefore the manufacturing process most closely resembles that utilized to make electronic products like PC mother boards.
A light-emitting diode (LED) is 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 forty years LEDs were primarily utilized in electronics devices to replace miniature bulbs. Inside the last decade, advances in the technology finally boosted light output high enough for LEDs to begin with to seriously contest with incandescent and fluorescent light bulbs. Just like 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 market is well suited to manufacture LED lighting. The process isn’t a lot distinct from building a computer motherboard. The companies making the LEDs are generally not in the lighting business, or it really is a minor a part of their business. They are usually semiconductor houses which can be happy cranking out their product, which explains why prices on high-output LEDs has fallen a lot within the last fifteen years.
LED bulbs are expensive partly since it takes numerous LEDs to obtain wide-area illumination as opposed to a narrow beam, and the assembly cost enhances the overall price. Additionally, assemblies composed of arrays of LEDs create more opportunities for product defects.
An LED light contains four essential components: an LED circuit board, a heatsink, an electrical supply, along with 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, and so the PCB used in lights is special. As opposed to the standard non-conductive sandwich of epoxy and fiberglass, the circuit board is laid out over a thin sheet of aluminum which works as a heatsink.
The aluminum PCB utilized in LED lighting is coated having a non-conducting material and conductive copper trace lines to form the circuit board. Solder paste is then applied inside the right places then Surface Mount Technology (SMT) machines put the tiny LED elements, driver ICs, along with other components onto the board at ultra high speeds.
The round form of a conventional light bulb implies that most LED printed circuit boards are circular, so for easy handling some 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 at the end the individual cupcakes are snapped clear of the tray.
Let’s have a look at the manufacturing steps for a typical LED light bulb designed to replace a standard incandescent bulb with the Edison Screw. You will see that it really is a very different process from your highly automated processes used to manufacture our familiar incandescent bulbs. And, despite everything you might imagine, individuals are still significantly an essential 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 hot air furnace that melts the solder paste), they are split up into the individual small circuit boards and power wires manually soldered on.
The small power supply housed within the body in the bulb undergoes a similar process, or may be delivered complete from another factory. In either case, the manufacturing steps are the same; 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 any given time. DIP refers back to the two parallel rows of leads projecting from your sides in the package. DIP components include all integrated chips and chip sockets.
While LED lights burn repeatedly longer than incandescent or CFLs and require not even 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 warmth from your dozen roughly LED elements towards the metal heatsink frame and so keep temperatures in check. Aluminum-backed PCBs are often called “metal core printed circuit boards,” and though manufactured from a conductive material the white coating is electrically isolating. The aluminum PCB is screwed in position inside the heatsink which forms the reduced one half of the LED bulb.
After this, the power connector board is fixed in position with adhesive. The tiny 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 in place with screws. A plastic shell covers the ability supply and connects with the metal heatsink and LED circuit board. Ventilation holes are included to enable heat to escape. Wiring assembly for plug socket requires soldering wires to the bulb socket. Then shell is attached.
Next, the completed LED light is sent to burn-in testing and quality control. The burn-in test typically can last for half an hour. The completed LED light will then be powered up to find out if it is working properly and burned set for thirty minutes. Additionally there is a high-voltage leakage and breakdown test and power consumption and power factor test. Samples from the production run are tested for top-voltage leaks, power consumption, and power factor (efficiency).
The finished bulbs pass through the last crimping step as the metal socket base is crimped in position, are bar-coded and identified with lot numbers. External safety labels are applied and the bulb is inked with information, including brand 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 ensure all the different areas of the LED light are tight, then its 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 methods these are manufactured and how that comes even close to the manufacture of traditional lights should help. However, it jrlbac reveals why the fee will fall pretty dramatically over the next couple of years. Just like the expense of manufacturing other semiconductor-based products has fallen dramatically because of standardization, automation along with other key steps along the manufacturing learning curve, the same inexorable forces will drive on the costs of LED bulb production.