What Is 3D Printing
3D printing is a technology that builds objects based on digital model files, using bondable materials such as powdered metal or plastic, and printing them layer by layer. The printed content comes from 3D models or other electronic data, and the printed 3D objects can have any shape and geometric characteristics.
Main 3D Printing Technologies
3D printing uses computer-aided design (CAD) to create three-dimensional objects through a layered method. Starting from the production of graphic models of the objects to be printed, these are usually designed using computer-aided design (CAD) software packages. Import the files to the 3D printer, and then the 3D printer will complete the work. According to different working principles, 3D printing technology can be divided into the following three types:
FDM(Fused Deposition Modeling) FDM technology to heat and melt the filamentous hot-melt material, and at the same time, under the control of the computer, the three-dimensional nozzle can selectively coat the material on the worktable according to the cross-sectional profile information, and form a layer after rapid cooling section. After the formation of one layer is completed, the machine table is lowered by the height of the one-layer thickness, then form the next layer, work repeatedly until the entire solid shape is formed.
SLS (Selective Laser Sintering) This technology uses powder spreading to spread a layer of powder material on the upper surface of the molded part and heat it to a temperature just below the sintering point of the powder. The control system controls the laser beam to be on the powder layer according to the cross-sectional profile of the layer. After scanning, the temperature of the powder rises to the melting point, sintering and bonding with the molded part below. After one layer is completed, the workbench is lowered by the height of the one-layer thickness, and the spreading roller spreads a layer of uniform and dense powder on it and sinters the section of the new layer until the entire model is completed.
SLA (Stereo Lithography Apparatus) The liquid tank is filled with liquid photosensitive resin, which will quickly cure under the ultraviolet laser beam emitted by the laser (the laser used in SLA and SLS is different, SLA uses ultraviolet laser, and SLS uses infrared laser). At the beginning of forming, the lifting worktable is below the liquid level, exactly one section thick. The laser beam focused by the lens scans the cross-sectional profile along the liquid surface according to the machine’s instructions. The resin in the scanning area quickly solidifies to complete the processing of a layer of cross-section and obtain a layer of plastic sheet. Then, the workbench is lowered by the height of the one-layer thickness, and then the other layer is cured. Such layers are superimposed to construct a three-dimensional entity.
Features of 3D printing service
1. Flexible Design: 3D printing allows for the design and printing of more complex designs than traditional manufacturing processes. More traditional processes have design restrictions that no longer apply with the use of 3D printing.
2. Print on Demand: Print on demand is another advantage as it doesn’t need a lot of space to stock inventory, unlike traditional manufacturing processes. This saves space and costs as there is no need to print in bulk unless required.
The 3D design files are all stored in a virtual library as they are printed using a 3D model as either a CAD or STL file, this means they can be located and printed when needed. Edits to designs can be made at very low costs by editing individual files without wastage of out-of-date inventory and investing in tools.
3. Fast Design and Production: Depending on a part’s design and complexity, 3D printing can print objects within hours, which is much faster than molded or machined parts. It is not only the manufacture of the part that can offer time savings through 3D printing but also the design process can be very quick by creating STL or CAD files ready to be printed.
4. Cost Effective: As a single-step manufacturing process, 3D printing saves time and therefore costs associated with using different machines for manufacture. 3D printers can also be set up and left to get on with the job, meaning that there is no need for operators to be present the entire time. As mentioned above, this manufacturing process can also reduce costs on materials as it only uses the amount of material required for the part itself, with little or no wastage. While 3D printing equipment can be expensive to buy, you can even avoid this cost by outsourcing your project to a 3D printing service company.
5. Environmentally Friendly: As this technology reduces the amount of material wastage used this process is inherently environmentally friendly. However, the environmental benefits are extended when you consider factors such as improved fuel efficiency from using lightweight 3D printed parts.
Drawbacks
1. Limited Materials: While 3D Printing can create items in a selection of plastics and metals the available selection of raw materials is not exhaustive. This is because not all metals or plastics can be temperature-controlled enough to allow 3D printing. In addition, many of these printable materials cannot be recycled and very few are food-safe.
2. Post Processing: Although large parts require post-processing, as mentioned above, most 3D printed parts need some form of cleaning up to remove support material from the build and to smooth the surface to achieve the required finish. Post-processing methods used include water jetting, sanding, a chemical soak and rinse, air or heat drying, assembly, and others. The amount of post-processing required depends on factors including the size of the part being produced, the intended application, and the type of 3D printing technology used for production. So, while 3D printing allows for the fast production of parts, the speed of manufacture can be slowed by post-processing.
3. Part Structure: With 3D printing (also known as Additive Manufacturing) parts are produced layer-by-layer. Although these layers adhere together it also means that they can delaminate under certain stresses or orientations. This problem is more significant when producing items using fused deposition modeling (FDM), while polyjet and multijet parts also tend to be more brittle. In certain cases, it may be better to use injection molding as it creates homogenous parts that will not separate and break.
4. Rapid Prototyping printing can manufacture parts within hours, which speeds up the prototyping process. This allows for each stage to be completed faster. When compared to machining prototypes, 3D printing is inexpensive and quicker at creating parts as the part can be finished in hours, allowing for each design modification to be completed at a much more efficient rate.
5. Strong and Lightweight Parts: The main 3D printing material used is plastic, although some metals can also be used for 3D printing. However, plastics offer advantages as they are lighter than their metal equivalents. This is particularly important in industries such as automotive and aerospace where light-weighting is an issue and can deliver greater fuel efficiency.
Also, parts can be created from tailored materials to provide specific properties such as heat resistance, higher strength, or water repellency.
6. Minimizing Waste: The production of parts only requires the materials needed for the part itself, with little or no wastage as compared to alternative methods which are cut from large chunks of non-recyclable materials. Not only does the process save on resources but it also reduces the cost of the materials being used.
7. Ease of Access:3D printers are becoming more and more accessible with more local service providers offering outsourcing services for manufacturing work. This saves time and doesn’t require expensive transport costs compared to more traditional manufacturing processes produced abroad in countries such as China.
8. Advanced Healthcare printing is being used in the medical sector to help save lives by printing organs for the human body such as livers, kidneys, and hearts. Further advances and uses are being developed in the healthcare sector providing some of the biggest advances from using the technology.
9. Restricted Build Size: 3D printers currently have small print chambers that restrict the size of parts that can be printed. Anything bigger will need to be printed in separate parts and joined together after production. This can increase costs and time for larger parts due to the printer needing to print more parts before manual labor is used to join the parts together.
10. Large Volumes: 3D printing is a static cost, unlike more conventional techniques like injection molding, where large volumes may be more cost-effective to produce. While the initial investment for 3D printing may be lower than other manufacturing methods, once scaled up to produce large volumes for mass production, the cost per unit does not reduce as it would with injection molding.
11. Design Inaccuracies: Another potential problem with 3D printing is directly related to the type of machine or process used, with some printers having lower tolerances, meaning that final parts may differ from the original design. This can be fixed in post-processing, but it must be considered that this will further increase the time and cost of production.
