Apple Watch Series 10 will use parts produced by 3D printing technology starting in the second half of this year. Apple experimented with 3D printing parts on last year’s Apple Watch Series 9, but did not mass-produce them. After extensive testing, the efficiency of 3D printing mass production seems to have improved significantly.
It is reported that the supplier of Apple Watch 3D printer components is Bright. Different from the previous one, Bright was an equipment supplier last year, but this year it changed to a parts supplier.
Apple’s suppliers have begun to substantially adopt this technology to replace traditional CNC machining methods for production. It can be seen that 3D printing technology is being used more widely. Cost advantage may be an important factor in Apple’s decision to use 3D printed parts, and the first use of 3D printed parts may be because this product is not as complex to manufacture as Apple’s other hardware products.
Over the past decade, 3D printing has only appeared in certain specific areas of industry. There has been controversy about the quality, materials, user experience and limited application scenarios of 3D printing, but this has not stopped the development of 3D printing technology. In the fields of dentistry and aerospace, 3D printing new technology has been steadily implemented, which has truly reduced costs and improved efficiency for the industry.
What is 3D printing technology?
There are two main traditional manufacturing methods – equal material manufacturing process, that is, forging and stamping are both plastic processing (or pressure processing), collectively called forging: Casting is to pour liquid metal into a cavity (called a cavity) that matches the shape of the part. For casting molds, the material can be sand, metal or even ceramics) and wait for it to cool and solidify to obtain parts or blanks; stamping relies on presses and molds to apply external force to plates, strips, pipes and profiles to make them A forming process that produces plastic deformation or separation to obtain workpieces (stamping parts) of the required shape and size. Subtractive manufacturing process generally refers to the process method of processing parts on CNC machine tools: turning, milling and planing are four basic processing methods, including turning, milling, planing and grinding. Different parts require There are different processing methods, and some parts require multiple methods to complete the processing of the parts.
The principle of 3D printing technology is mainly based on the additive manufacturing technology of “additive manufacturing”. It converts digital models into physical models by stacking materials layer by layer to achieve rapid manufacturing of objects. In the 3D printing process, each layer represents a cross-section of the layer of objects the printer needs to build. Based on each layer of digital model information, the printer controls nozzles, laser beams, or other mechanical components to accurately deposit the material in the correct location. Interlayer bonding is accomplished by melting, solidifying, or bonding materials to ensure that the entire object is structurally sound. This layer-by-layer approach allows for the fabrication of very complex shapes and structures, making 3D printing a very flexible and innovative manufacturing technology.
Digital Design Model: The first step in printing is to create a digital design model. This model can be created with computer-aided design (CAD) software or by scanning a physical object with a 3D scanner. CAD software allows users to create, edit and optimize three-dimensional models on a computer that can represent objects of any shape and size.
Slicing: Once you have the digital model, the software cuts it into thin layers, called slices. These layers are typically very thin and can be tens to hundreds of microns thick. Each layer represents a cross-section of a layer of objects that the printer needs to build.
Layer-by-layer: The 3D printer builds the object by stacking material layer by layer based on these slices. Depending on the printing technology, these materials can be plastic filaments, powders, resins, etc. Based on each layer of digital model information, the printer controls nozzles, laser beams, or other mechanical components to accurately deposit the material in the correct location.
Interlayer bonding: Each layer of material needs to be bonded to the next layer after being stacked to ensure the structural stability of the entire object. This may be accomplished by melting, solidifying, or bonding the material, and different printing technologies have different ways of bonding between layers.
Repeated accumulation: The printer repeats this layer-by-layer accumulation process until all layers are accumulated to form the final three-dimensional object.
3D printing technology is called “the idea of the last century, the technology of the last century, and the market of this century.” In 1860, Frenchman François Willème first designed a multi-angle imaging method to obtain three-dimensional images of objects, and called this technology photosculpture. 24 cameras were arranged in a 360-degree circle to shoot simultaneously, and then Use a scale plotter connected to a cutting machine to outline the model.
In 1892, Joseph Blanther proposed the “layered topographic map” for the first time in public, and invented the technology of using wax plates to create contour topographic maps. In 1940, Perera proposed an idea that coincided with Blanther’s. He proposed a method of cutting cardboard along contour contours and then laminating them to create three-dimensional topographic maps. Additive manufacturing follows this principle.
In 1979, Professor Takeo Nakagawa of the Institute of Production Technology of the University of Tokyo invented the stacked model modeling method. In 1980, Hideo Hisada of the Nagoya City Industrial Research Institute in Japan invented a three-dimensional model additive manufacturing method using photosensitive polymer molding. In May of the same year, he applied for the first patent related to this technology. In 1986, American inventor Charles W. Hull established 3D Systems, developed the STL file format, triangulated CAD models, and became one of the industry standards for CAD/CAM system interface file formats; 1988 In 2016, two years after its establishment, the company launched the world’s first 3D industrial printer SLA-250 based on stereolithography SL technology.
There was no name for 3D printing before, and the name more accepted in the research field at that time was “rapid prototyping”. In 1993, MIT professor Emanual Saches, as the main developer, and others co-invented 3DP (Three-Dimensional Printing), which is three-dimensional printing technology. It used inkjet printers that were already popular at the time to replace the ink in the ink cartridge with glue. The sprayed glue is used to bond the powder on the powder bed, and as a result, some three-dimensional objects can be printed. They excitedly called this printing method 3D Printing and their modified printer a 3D printer. Since then, the term 3D printing has gradually become popular, and all rapid prototyping technologies are collectively referred to as 3D printing technology.
3D printing technology classification
A variety of 3D printing technologies have been developed with different functions. According to ASTM standard F2792, ASTM divides 3D printing technologies into seven categories: directed energy deposition, material extrusion, material jetting, bonded jetting, powder bed fusion, sheet lamination, and reductive photopolymerization.
·Directed Energy Deposition
Directed energy deposition is a more complex printing process often used to repair or add additional material to existing components. Can be used on ceramics, polymers, but often on metals and metal-based mixtures, in wire or powder form.
· Materials Extrusion
Material extrusion As the name suggests, material is extruded through a nozzle. Typically the material is a plastic filament that is melted and extruded through a heated nozzle. The printer places the material on the build platform along a process path derived through software, and the filament cools and solidifies to form a solid object.
· MaterialsJetting
In material jetting, a printhead drops in cured photosensitive material, selectively depositing building materials drop by drop, building parts layer by layer under ultraviolet (UV) light. The nature of the material jetting process allows different materials to be printed on the same object, making it possible to create parts in a variety of colors and textures.
·Powder Bed Fusion
Powder bed fusion thermal energy selectively melts powder particles (plastic, metal, or ceramic) within a build area to create a solid object layer by layer. Powder bed fusion 3D printers spread a thin layer of powdered material over the print bed, typically using a type of blade, roller or wiper. The energy from the laser fuses specific points on the powder layer, then another powder layer is deposited and fused to the previous layer. The process is repeated until the entire object is manufactured, with the final product being wrapped and supported by unfused powder.
· Binder Jetting
Binder jetting is the selective bonding of a liquid adhesive to an area of a layer of powder. This type of technology combines the characteristics of powder bed fusion and material jetting. Similar to PBF, binder jetting uses powdered materials (metals, plastics, ceramics, wood, sugar, etc.) and, like material jetting, a liquid binder polymer is deposited from an inkjet. Whether it is metal, plastic, sand or other powdered materials, the binder jetting process is the same.
· Sheet lamination
Sheet lamination is the stacking and lamination of very thin sheets of material together to create a 3D object or stack, which is then mechanically or laser cut to form the final shape. Layers of material can be fused together using a variety of methods, including heat and sound, depending on the material, which ranges from paper to polymers to metals. When parts are laminated and then laser cut or machined into the desired shape, more waste is generated than with other 3D printing technologies.
· Vat Photopolymerization
Reductive photopolymerization typically refers to the use of laser, light, or UV light to cure a photoreactive polymer. In other words, the light is precisely directed at specific points or areas of the liquid plastic to harden it. After the first layer cures, the build platform will move up or down (depending on the printer) a small amount (usually between 0.01 and 0.05 mm) and the next layer solidifies, joining the previous layer. Repeat this process layer by layer until a 3D part is formed. After the 3D printing process is complete, the object is cleaned to remove remaining liquid resin and post-cured (in sunlight or in a UV chamber) to enhance the mechanical properties of the part.
Advantages of 3D printing technology
Compared with equal-material manufacturing processes and subtractive manufacturing processes, 3D printing technology has many advantages. For items with complex geometric structures (such as items with very complex topological structures or cavity structures inside), traditional manufacturing processes cannot process them, and the items need to be disassembled, processed separately and then assembled. 3D printing decomposes objects into 2D areas layer by layer, so there is no problem in processing any complex object. The processing accuracy only depends on the smallest material particles that the printer can output.
In some cases, when new parts need to be manufactured or changes need to be made on the original parts, the digital 3D design files can be easily modified without requiring significant reassembly of the production line; in contrast, when the part design needs to be modified, Traditional manufacturing methods such as injection molding or die casting require costly retooling of the production line.
3D printing technology can manufacture products in a “decentralized” manner, which helps reduce the time it takes for products to reach customers, and also helps reduce costs, energy consumption and the environmental impact caused by transportation. The ability of 3D printing to “manufacture on demand” helps manufacturers reduce inventory and has low production preparation costs. In addition, it is suitable for small batch production, which can effectively reduce funds frozen in inventory and related storage and insurance costs.
Disadvantages of 3D printing technology
As a young molding process, 3D printing still has many shortcomings. In 3D printing, the 3D model output is a physical model, and what needs to be considered more is the physical properties (mechanical properties and functional properties) of the physical model. The two major shortcomings of limited mechanical capabilities and insufficient surface accuracy limit the application of 3D printing technology in other fields. If 3D printing wants to be applied in more fields, these shortcomings need to be improved, or the efficiency of the subsequent process must be improved.
Given a 3D digital model, it needs to be discretized into a triangular mesh (STL file), then added with filling structures and support structures, then slice calculation and path planning, and finally sent to a 3D printer to output a physical model through G code. This process is the main work of the slicing engine software of the 3D printer, and involves a lot of geometric calculations. In many cases, the input 3D model has some problems and cannot be directly output to the 3D printer. For example: the topology of the 3D model itself is not standardized and cannot be sliced; printing fails due to the presence of hanging parts; the size of the model is too large. Exceeding the size limit that the printer can print; failing to consider stability, resulting in printed objects that cannot be placed normally, etc.
At this stage, the actual use of 3D printing still falls into the category of rapid prototyping, which provides companies with the manufacturing of product prototypes before producing formal products. It is also called a prototype in the industry. Therefore, the 3D printing molding process currently exists as a complementary method to traditional manufacturing processes, and it will take some time to become a mainstream manufacturing technology.
The future of 3D printing technology
Different combinations of materials can produce objects with different physical properties. Combination optimization is also a spatial distribution optimization of geometry; the design and optimization of different combination materials, functional materials, gradient materials, and the use of multiple material mixed printing are directions worth exploring in 3D printing technology. . Hybrid printing refers to the processing of two different mechanisms on one device, such as 3D printing and cutting processing, electric machining and ultrasonic processing, etc.
Can this new fusion technology replace the original independent 3D printing and CNC subtractive manufacturing and become a new processing method? If you want to achieve hybrid printing, you need to work hard on both hardware and software. In October 2020, the U.S. Department of Commerce added six emerging technologies to the Department of Commerce Control List of the Export Administration Regulations, including hybrid additive manufacturing, involving hardware manufacturing equipment and computer numerical control software. The United States puts hybrid additive manufacturing technology and semiconductor technology together, which is enough to prove the importance of these technologies.
Research on mechanism design of 3D printing technology is still in its infancy. The mechanical structure of 3D printers is relatively simple compared with other manufacturing methods. People’s longing for robots is both an opportunity and a challenge for the research direction of 3D printing mechanism design. . How to design dynamic 3D printing models and even 3D printing robots more simply and efficiently may also become the focus of future research in this area.
