3D printing combines precision digital technology, factory repeatability and craftsman design freedom to free up human ability to create things. This article is a summary of the convenience of the current 3D printing technology, selected from the book "3D printing: from imagination to reality" by CITIC Publishing House.
When most people first heard about 3D printing, they thought of old-fashioned, common desktop printers. The biggest difference between inkjet printers and 3D printers is the dimensional problem. Desktop printers are two-dimensionally printed, color ink is applied to flat paper, and 3D printers can create three-dimensional objects that are held on the hand. The 3D printer manufactures products by stacking raw materials in layers according to computer instructions. For most of human history, we manufacture new physical objects by cutting raw materials or by molding.
The technical name for 3D printing is “additive manufacturingâ€, which is a more appropriate description of the actual printing process. 3D printing's unique manufacturing technology allows us to produce items of all shapes and sizes that we have never seen before. 3D printing is not a new technology, and 3D printers have been working silently for decades in manufacturing machine shops. In the past few years, 3D printing technology has developed rapidly due to computing power, new design software, new materials, innovation promotion and Internet advancement.
The computer plays a key role in the 3D printing process, and without the instructions from the computer, the 3D printer will crash. The prerequisite for a 3D printer to function properly is to enter a well-designed electronic blueprint or design file that tells the 3D printer where to place the raw materials. In fact, a 3D printer without a computer and design files is useless, just like an iPod without music.
The 3D printing process is as follows: The 3D printer, under the guidance of the design document instructions, first ejects solid powder or molten liquid material to cure it into a special flat layer. After the first layer is cured, the 3D printer print head returns, forming another thin layer outside the first layer. After the second layer is cured, the printhead returns again and another thin layer is formed on the outside of the second layer. In this way, the thin layer eventually accumulates into a three-dimensional object.
3D printers do not make articles by cutting or mold molding like traditional manufacturing machines. The method of forming solid objects by layering increases the scope of the digital concept from a physical point of view. For shape designs that require precise internal recesses or interlocking portions, 3D printers are the preferred processing equipment that can be implemented in the physical world.
Ten advantages of 3D printing
People from a variety of industries with different backgrounds and levels of expertise are described in a similar manner, and 3D printing helps them reduce major cost, time and complexity barriers.
Advantage 1: Manufacturing complex items does not increase costs. In the case of conventional manufacturing, the more complex the shape of the object, the higher the manufacturing cost. For 3D printers, the cost of making complex-shaped items does not increase, and creating a gorgeous, complex-shaped item does not consume more time, skill, or cost than printing a simple square. Manufacturing complex items without increasing costs will break the traditional pricing model and change the way we calculate manufacturing costs.
Advantage 2: Product diversification does not increase costs. A 3D printer can print many shapes, and it can make different shapes of items every time like a craftsman. Traditional manufacturing equipment has fewer features and a limited variety of shapes. 3D printing eliminates the cost of training mechanics or purchasing new equipment. A 3D printer requires only a different digital design blueprint and a new batch of raw materials.
Advantage 3: No assembly is required. 3D printing enables the components to be integrally formed. Traditional mass production is based on assembly lines where machines produce the same parts and are then assembled by robots or workers (even across continents). The more components a product has, the more time and cost it takes to assemble. The 3D printer can print a door and the matching hinges at the same time by layering, without assembly. Omission of assembly shortens the supply chain and saves labor and transportation costs. The shorter the supply chain, the less pollution.
Advantage 4: Zero time delivery. The 3D printer can print on demand. Instant production reduces the physical inventory of the company. Companies can use 3D printers to create special or customized products to meet customer needs based on customer orders, so new business models will be possible. Zero-time delivery can minimize the cost of long-haul transportation if the items needed are near-on-demand.
Advantage 5: The design space is unlimited. Traditional manufacturing techniques and products manufactured by artisans are limited in shape, and the ability to make shapes is subject to the tools used. For example, a conventional wooden lathe can only produce round items, a rolling mill can only process parts assembled with a milling cutter, and a molding machine can only produce a molded shape. 3D printers can break through these limitations, open up huge design space, and even make shapes that may only exist in nature today.
Advantage 6: Zero skill manufacturing. Traditional craftsmen need a few years of apprenticeship to master the skills they need. Mass production and computer-controlled manufacturing machines reduce the skill requirements, whereas traditional manufacturing machines still require skilled professionals to make machine adjustments and calibrations. The 3D printer obtains various instructions from the design file and does the same complicated items. The 3D printer requires less operating skills than the injection molding machine. Unskilled manufacturing opens up new business models and provides new ways of production in remote environments or in extreme situations.
Advantage 7: No space, portable manufacturing. In terms of unit production space, 3D printers are more capable of manufacturing than traditional manufacturing machines. For example, an injection molding machine can only manufacture items that are much smaller than itself, and in contrast, a 3D printer can produce items as large as its printing station. After the 3D printer is debugged, the printing device can move freely, and the printer can make items larger than itself. The high capacity per unit of space makes 3D printers suitable for home or office use because they require less physical space.
Advantage 8: Reduce waste by-products. Compared to traditional metal fabrication techniques, 3D printers produce less by-products when making metal. The waste of traditional metal processing is staggering, and 90% of the metal raw materials are discarded in the factory floor. 3D printing reduces the amount of wasted metal. As printing materials advance, "net forming" manufacturing can become a more environmentally friendly process.
Advantage 9: Unlimited combination of materials. For today's manufacturing machines, combining different raw materials into a single product is difficult because traditional manufacturing machines cannot easily combine multiple raw materials during cutting or molding. With the development of multi-material 3D printing technology, we have the ability to combine different raw materials. Raw materials that were previously unmixed will form new materials that have a wide variety of tones and unique properties or functions.
Advantage 10: Accurate physical copying. Digital music files can be copied endlessly and the audio quality does not drop. In the future, 3D printing will extend digital precision to the physical world. Scanning technology and 3D printing technology will work together to improve the resolution of morphological transformations between the physical world and the digital world. We can scan, edit and copy solid objects, create accurate copies or optimize originals.
Some of the above advantages have been confirmed, and others will become a reality in the next one or two decades (or thirty years). 3D printing breaks through the traditionally long-established traditional manufacturing restrictions and provides a stage for future innovation.
There are two types of EPON systems: one is a system that uses 2 wavelengths; the other is a system that uses 3 wavelengths.
For a two-wavelength system, its downlink wavelength is 1510 nm to transmit downlink voice, data and digital video services; the uplink wavelength is 1310nm to transmit uplink voice and video on-demand and download data request signals. The two-way transmission rate of this system is 1.25 Gb/s, even if the OBD split ratio is 32, it can transmit 20km.
For the three-wavelength system, in addition to the downlink wavelength of 1510 nm and the uplink wavelength of 1310 nm, a transmission window with a downlink wavelength of 1550 nm (1530 ~ 1565 nm) is added. The new window is used to transmit downlink CATV service or DWDM service. The CATV service can be either an analog video signal or an MPEG-2 digital video signal. When the splitting ratio of this system is 32, it can transmit 18 km.
EPON is located between the business network interface and the user network interface, connected to the business node through SNI, and connected to user equipment through UNI. EPON system is mainly composed of optical line terminal (OLT), optical distribution network (ODN) and optical network unit.
In the EPON system, the OLT is not only a switch or router, but also a multi-service providing platform, which provides optical fiber interfaces for passive optical fiber networks. According to the development trend of Ethernet to metropolitan area network and wide area network, OLT will provide 1 Gb/s and 10 Gb/s Ethernet interfaces. In addition to supporting traditional voice, ordinary telephone lines, and other types of T1/E1 interfaces, the OLT also supports SONET connections at ATM, FR, and OC3/12/48/192 rates. The OLT in the EPON can be configured with multiple optical line cards as required to connect with 16 to 64 ONUs. In EPON, the maximum distance from the OLT to the ONU can reach 20 km. If an optical fiber amplifier (active repeater) is used, the distance can be extended.
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