One-hundred-and-thirty years back, Thomas Edison completed the very first successful sustained test of the incandescent light bulb. With some 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 can ultimately replace Edison’s bulbs with a far more energy-efficient lighting solution. Solid state LED lighting will ultimately replace almost all of the countless billions of incandescent and fluorescent lights in use around the globe today. In reality, as being a step along this path, The President last June introduced new, stricter lighting standards that will support the phasing out of incandescent bulbs (which already are banned in areas of Europe).
To understand exactly how revolutionary Lamp bar module power supply are in addition to why they may be still expensive, it is actually instructive to check out how they are produced and to compare this for the manufacture of incandescent bulbs. This short article explores how incandescent bulbs are produced then contrasts that process having a description in the typical manufacturing process for LED bulbs.
So, let’s start with taking a look at how traditional incandescent bulbs are manufactured. You will notice that this is a classic example of an automated industrial process refined in over a century of experience.
While individual incandescent bulb types differ in proportions and wattage, every one of them have the three basic parts: the filament, the bulb, as well as 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 into a borax answer to 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 lifetime 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 referred to as the “Edison screw base.” Aluminum is utilized on the outside and glass utilized to insulate the inside the base.
Originally made by hand, light manufacturing is now almost entirely automated. First, the filament is manufactured employing a process known as drawing, where tungsten is blended 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 a metal bar known as a mandrel so that you can mold it into its proper coiled shape, and then it is heated in a process referred to 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 can be either pressed on the end of 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 a lot more than 50,000 bulbs hourly. After the casings are blown, they are cooled and after that cut from the ribbon machine. Next, the within the bulb is coated with silica to eliminate the glare the result of a glowing, uncovered filament. The label and wattage are then stamped onto the outside surface of each casing.
Fourth, the bottom of the bulb is also constructed using molds. It is made with indentations within the shape of a screw so it can certainly squeeze into the socket of a light fixture.
Fifth, after the filament, base, and bulb are produced, these are 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 air within the bulb is evacuated, and the casing is filled with the argon and nitrogen mixture.
Finally, the base and also the bulb are sealed. The base slides on the end in the glass bulb to ensure that not one other material is required to have them 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 certain proper electrical contact. After testing, bulbs are placed inside their packages and shipped to consumers.
Light bulbs are tested for both 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 provides an exact measure of how much time the bulb will last under normal conditions. Tests are performed whatsoever manufacturing plants along with at some independent testing facilities. The average lifetime of the standard household bulb is 750 to 1,000 hours, depending on wattage.
LED lights are made around solid-state semiconductor devices, and so the manufacturing process most closely resembles that utilized to make electronic products like PC mother boards.
An easy-emitting diode (LED) is really a solid state electrical circuit that generates light from the movement of electrons in a semiconductor material. LED technology has been around since the late 1960s, but for the first forty years LEDs were primarily used in electronics devices to replace miniature light bulbs. Within the last decade, advances in the technology finally boosted light output high enough for LEDs to start to seriously contend with incandescent and fluorescent light bulbs. Just like many technologies, as the cost 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. This process isn’t a great deal distinct from building a computer motherboard. The businesses making the LEDs themselves are generally not within the lighting business, or it is a minor 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 so much in the last 20 years.
LED bulbs are expensive to some extent as it takes numerous LEDs to have wide-area illumination instead of a narrow beam, and the assembly cost adds to 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, as well as a shell. The lights begin as bare printed circuit boards (PCB) and high luminance LED elements arrive from separate factories which concentrate on making those components. LED elements themselves create a 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 presented on the thin sheet of aluminum which acts as a heatsink.
The aluminum PCB found in LED lights are coated with a non-conducting material and conductive copper trace lines to create the circuit board. Solder paste is then applied within the right places and then Surface Mount Technology (SMT) machines position the tiny LED elements, driver ICs, along with other components onto the board at ultra high speeds.
The round model of a regular bulb means 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 are prepared for. Consider it just like a cupcake tray moving from one machine to the next along a conveyor belt, then at the conclusion the individual cupcakes are snapped free from the tray.
Let’s take a look at the manufacturing steps for any typical LED light bulb meant to replace a standard incandescent bulb with the Edison Screw. You will find that it really is a totally different process through the highly automated processes used to manufacture our familiar incandescent bulbs. And, despite whatever you might imagine, people are still greatly an essential part of manufacturing process, and not merely 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 may be split up to the individual small circuit boards and power wires manually soldered on.
The small power supply housed in the body from the light experiences an identical process, or could be delivered complete from another factory. In either case, the manufacturing steps are identical; first the PCB passes through SMT lines, then 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 through the sides in the package. DIP components include all integrated chips and chip sockets.
While LED lights burn several times more than incandescent or CFLs and require not even half the power, they need some type 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 temperature from the dozen or so LED elements to the metal heatsink frame and thus keep temperatures under control. Aluminum-backed PCBs are occasionally 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 lower half of the LED bulb.
After that, the ability connector board is fixed set up with adhesive. The tiny power supply converts 120/240V AC mains capability to a reduced voltage (12V or 24V), it fits in 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 using the metal heatsink and LED circuit board. Ventilation holes are included to allow heat to escape. 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 will last for half an hour. The completed LED light will then be powered up to determine if it is in working order 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 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 in position, are bar-coded and identified with lot numbers. External safety labels are applied as well as the bulb is inked with information, including brand and model number. Finally, all that’s left is always to fix on the clear plastic LED cover that is glued in place.
After having a final check to make certain all the different areas 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 bulbs are extremely expensive today, this explanation of how they are manufactured and how that compares to the creation of traditional light bulbs should help. However, it jrlbac reveals why the cost will fall pretty dramatically on the next couple of years. Just like the price of manufacturing other semiconductor-based products has fallen dramatically due to standardization, automation along with other key steps over the manufacturing learning curve, the identical inexorable forces will drive on the costs of LED bulb production.