What is 3D Printing? | What is additive manufacturing?
The phrase 3D printing refers to processes that produce three-dimensional things one incredibly thin layer at a time. The melted or partially melted substance in each subsequent layer adheres to the one before it. Computer-aided design (CAD) software is used to generate files that, in essence, slice objects into incredibly thin layers. Components are digitally described by CAD programme. The path of a nozzle or print head as it precisely deposits material upon the previous layer is guided by this CAD information. Materials combine to form three-dimensional objects as they cool or cured. A wide range of materials, including metal alloys, thermoplastics, thermoset polymers, and composites, can be used in additive manufacturing, depending on the 3D printing method and application. A relatively recent method of production is additive manufacturing, or 3D printing. Rapid prototyping was an early use for additive manufacturing, and it was immediately embraced for usage with polymer materials. Because the procedure required no tools, prototypes could be quickly made and tested for shape, fit, and function, allowing for quick innovation in product creation. The stereo lithography technique, in which thin layers of UV-sensitive resin were cemented with a laser, served as the foundation for the earliest AM machines, or 3D printers. The first company to put a commercial stereo lithography machine on the market, 3D Systems, commercialized this method in 1987. Shortly after, several polymer-based 3D printing technologies reached the market, the most noteworthy of which were fused deposition modelling (FDM), a Material Extrusion (MEX)-based process, and selective laser sintering.
3D printing technology can be broadly divided into three types
(a) The first of these is sintering, which involves heating the material without liquefying it to produce intricate, high-resolution shapes. While selective laser sintering employs a laser to make the particles of thermoplastic powder stick together, direct metal laser sintering uses metal powder.
(b) With the second AM technique, the materials are completely melted. This technique uses electron beam melting and direct laser metal sintering to melt layers of metal powder.
(c) The third broad technology category is stereo lithography, which employs a method called photo polymerization in which an ultraviolet laser is blasted into a vat of photopolymer resin to produce torque-resistant ceramic pieces capable of withstanding high temperatures.
How Does 3D Printing Works
(a) Modelling
The first stage in 3D printing is modelling. Object models are often created by manufacturing organisations utilising a specialised computer programme called a computer-aided design (CAD) package. The object model is finished and saved in the stereo lithography (.STL) or additive manufacturing file (AMF) formats.
(b) Export the .STL File
You must download or export the STL file after creating or selecting a design. The data about our hypothetical 3D item is kept in the STL file.
(c) Slicing
When you have a developed model, you can utilise specific slicing software to slice the model. Slicing serves as a tool for the 3D printer to determine the path and quantity of filament needed to manufacture the model. Powerful slicing software called Idea Maker can provide customised setups for various printers, filaments, and model designs.
(d) Choose printing Parameters
The next step is to choose the various specifications for your product and the printing procedure. This includes deciding on the size and placement of your print.
(e) Printing
The object will be built up by the printer layer by layer. The task can be completed in a few minutes or over the course of several hours, depending on the size of your object, your printer, and the materials used.
There may be extra post-processing stages after printing, such as painting, brushing off powder, etc., depending on what you want the final product to be or the material you used.
(f) Post-processing
Parts created using 3D printing techniques typically need some sort of post-production work. Post-processing is the term for this crucial stage of 3D printing. Post-processing, in the context of 3D printing, broadly refers to any operation that must be performed on a printed component or any method applied to improve the final product. Consider the treatment and refinement of 3D-printed items as a last touch. Removing support or extra material, washing and curing, sanding or polishing a model, and painting or colouring a model are all choices for post-processing 3D printed items.
Which are the various 3D printing methods?
1. Vat photo polymerization
Vat Photo Polymerization is a form of additive manufacturing that uses light-activated polymerization to selectively cure photopolymer liquid resin in order to create 3D objects. A photopolymer, also known as light-activated resin, is a type of polymer that changes the way its molecules behave when it is subjected to light, typically light that is in the ultraviolet or visible spectrum of the electromagnetic spectrum. All types of vat photo polymerization printers employ special resins called photopolymers as the printing medium. The molecules of liquid photopolymers swiftly link together and cure into a solid state when exposed to particular wavelengths of light; this process is known as photo polymerization. Using data from a CAD file, the printer controls a light source to selectively cure the liquid photopolymer into a solid layer. The process is then repeated for the successive layers, up till the full design is produced, submerging the construction platform once more in the resin that was previously used.
Types of Vat photo polymerization
1.1 Stereo lithography (SLA)
SLA is known for being the first 3D printing method ever developed. Chuck Hull created stereo lithography in 1986; he applied for a patent on the idea and established the business 3D Systems to market it. Galvanometers or galvos, which are mirrors, are used in a SLA printer, one on the X-axis and the other on the Y-axis. These galvos quickly direct a laser beam across a resin vat, selectively curing and hardening a cross-section of the object inside this building region, and layer by layer builds it up. A solid-state laser is typically used by SLA printers to cure items.
1.2 Digital light processing (DLP)
In DLP, a shallow vat holds a liquid photopolymer resin. The DLP approach employs a video projector equipped with a digital micro-mirror device, a micro-opto-electromechanical mirror array, to modulate a collimated UV light source that is then focused to an imaging plane positioned on the bottom surface of a transparent vat. The work piece is pushed upward layer by layer as the desired geometry is constructed by modulating image masks corresponding to a sliced representation of the created geometry as the vertical stage of the machine. Based on the form of the layer, UV light is used to project the image of each layer across the entire surface.
1.3 Continuous liquid interface production (CLIP)
Continuous Liquid Interface Production, or CLIP, is an additive manufacturing technique that creates components with exceptional mechanical qualities by combining UV light, oxygen, and programmable liquid resin. It is sometimes referred to as Digital Light Synthesis (DLS) technology, and it entails producing objects as a whole rather than layer by layer as with other 3D printing techniques. In comparison to existing additive manufacturing technologies, this allows for up to 100 times faster production times. The synthetic resin is put into a flat container as part of the CLIP procedure. There, a UV laser projector placed underneath the container melts the resin before solidifying it into the desired shape. The substance and projector are separated by a window that lets air and light in. Through this window, oxygen is slowly released to stop the liquid resin from setting up too quickly.
2. Material Jetting
Similar to 2D printers in operation, material jetting (MJ) is an additive manufacturing technique. In material jetting, a print head sprays droplets of a photosensitive substance that solidifies under ultraviolet (UV) light, layer-by-layer constructing a part. The thermoset photopolymers (acrylics), which are available in liquid form, are the materials utilised in MJ. High dimensional accuracy components with a very smooth surface finish are produced by MJ 3D Printing. Material jetting offers multi-material printing and a large selection of materials, including totally transparent and rubber- and ABS-like polymers. These features make MJ a particularly alluring choice for the production of visual prototypes and tooling. Drop-On-Demand (DOD) print heads are used in a version of the MJ process to distribute viscous liquids and produce pieces that resemble wax. Nearly all of the process parameters in material jetting are pre-set by the machine’s manufacturer. Due to the intricate physics involved in droplet production, even the layer height is related to each distinct material. Material jetting typically uses layers that range in height from 16 to 32 microns. One of the most accurate 3D printing techniques is material jetting. Dimensional precision for MJ systems is 0.1%, with a common lower limit of 0.1 mm. Although warping can happen, it is less frequent than with other technologies, such FDM or SLS, because printing takes place at close to ambient temperature. Because of this, extremely large pieces can be produced precisely.
3. Binder Jetting
An additive manufacturing technique called “binder jetting” uses targeted deposition of a liquid binding agent to bind powder particles together. After that, the material is bonded together to create an item. The binder is carefully deposited into the powder by the print head. A second layer of powder is distributed, and binder is then applied while the job box is lowered. The part evolves over time as layers of powder and binder are added. Metals, sand, and ceramics are just a few of the materials it can print. Sand is one of the resources that don’t need to be processed further. Depending on the application, other materials are commonly cured, sintered, and occasionally infiltrated with another material. Similar to conventional paper printing, hot iso-static pressing can be used to generate high densities in solid metals. As it flows through the layers of powder, which are created like sheets of paper, the binder acts like ink. Binder jetting is frequently regarded as the ideal choice for online 3D printing in India because of its capacity to build solid layers. Large things can also be printed using India’s binder jetting 3D printing technology. Binder jetting has been used to create architectural constructions that are the size of rooms.
4. Material Extrusion
A spool of material (often thermoplastic polymer) is forced through a heated nozzle in a continuous stream and selectively placed layer by layer to construct a 3D object using the additive manufacturing (AM) approach of material extrusion. Material extrusion techniques include fused filament fabrication (FFF) and fused deposition modelling (FDM). Compared to other forms of additive manufacturing, material extrusion is often slower and less precise. However, material extrusion technology and appropriate raw materials, such as Nylon and ABS plastic, are widely available and reasonably priced. As a result, material extrusion is the most widely used method for hobbyist-grade 3D printing at home. Material extrusion is frequently utilised in manufacturing and industrial contexts to create non-functional prototypes or cost-effective rapid prototyping for several iterations of the same thing. The basic idea behind material extrusion AM techniques is to extrude heated plastic via a nozzle and eject it onto a build surface.
4. 1 Fused Deposition Modelling (FDM)
Since FDM is the most popular method of additive manufacturing and is therefore the most accessible to both industry and hobbyists, it is what most people think of when they think of 3D printing. Since many thermoplastics can be printed with FDM, it also has a sizable array of materials that can be used. ABS and PLA are the two polymers most frequently used.
In FDM, a spool of plastic is used to feed a filament—a thread of plastic—through a nozzle. The nozzle is located on a print head that mechanically forces filament through a cold portion, melts the filament in a hot section, and then extrudes the melted filament through the nozzle. The plastic is now melted and extruded, and it is printed continuously right onto a build’s surface. To regulate where the plastic is put, the print nozzle travels in the x-y plane. After the layer is finished, the platform the object is on can shift slightly downward in the z direction so that the following layer can be constructed. Since the plastic is heated when it is deposited, it can soften and bond to the surface of layers below by fusing to them. Due to the fact that this fuse is weaker than the extruded thread of material, printed items are often weaker in the z-direction. This results in anisotropic qualities.
4.2 Fused Filament Fabrication (FFF)
A plastic wire is melted and extruded via a nozzle using an FFF machine. On a build platform, the molten material is applied and allowed to cool and cure. Layer after layer of molten filament is deposited during 3D printing using FFF, or fused filament fabrication. It is a technique for 3D printing that is employed in a variety of fields including aircraft, architectural, automotive, moulding, industrial design, and many others to produce prototypes, tools, as well as finished goods. The material is fed in the form of a filament, which is a plastic thread. The embossing of the filament and layer-by-layer application of material results in the creation of the finished model.
5. Powder Bed Fusion
A powdered raw material is used in the additive manufacturing technique known as powder bed fusion. The powdered material is fused together in predetermined patterns layer by layer by applying an energy source selectively. This area of additive manufacturing includes a variety of distinct technologies. The best applications for powder bed fusion are high-precision designs and quick prototyping. A top-tier 3D printing technique is powder bed fusion. It stands out since it is generally appropriate for industrial or commercial purposes.
5.1 Multi Jet Fusion (MJF)
Hewlett-Packard created the exclusive PBF technique known as MJF, which can produce parts in as little as one day. HP does this by using a multi-station strategy for powder bed fusion. Similar to previous techniques, powdered material (nylon/other polyamides) is fed into a build chamber by a roller and is gradually built up in a layer-by-layer process. However, an inkjet array selectively applies fusing and detailing agents across the layer of powder, which are then applied across the layer of powder and selectively applied to solidify upon the second pass with a thermal energy source. More powder is added as the build platform descends, and so on until the entire part is printed. As the agents sprayed onto the powder chemically react and fuse particles upon contact with heat, this procedure uses substantially less energy. The item is taken out of the printer after printing (while still inside the modular powder bed) and put in a different processing station where the loose powder is recovered and the pieces are bead blasted before being used. Because it doesn’t use laser technology and generates a lot less heat than other thermal designs, the PBF process stands apart from the other types. MJF has a high output volume, offers high-quality surface finishes, fine feature resolution, and uniform mechanical qualities throughout all parts. MJF’s modular, station-based design is simple to use and enhanced by software that makes understanding how to utilise this technology simpler than with other PBF printers.
5.2 Selective Laser Sintering (SLS)
Selective laser sintering (SLS) technique was created and patented in 1989 by Carl Deckard and Joe Beaman. A tiny layer of metal powder is targeted with a powerful laser in this technique. After heating the layer, the subsequent procedures for attaching the metal particles together begin. In order to complete this stage, material must be moved from inside the powder to the points and regions where particles are in contact with one another. Volume diffusion, grain-boundary diffusion, surface diffusion, viscous or plastic flow are among the five potential transport mechanisms. High porosity is a characteristic of SLS-made elements.
5.3 Direct Metal Laser Sintering (DMLS)
Selective laser melting is another name for the standard 3D printing or additive manufacturing process known as direct metal laser sintering (DMLS) (SLM). In this method, a CAD (computer-aided design) file is used to direct the laser as it is pointed at the powder bed to manufacture each layer of a part. The machine applies more powder to the part and repeats the procedure once the first layer has been produced. Printing accurate, high-resolution parts with intricate geometries is perfectly suited for this method. In a digital process that does not require actual moulds, DMLS machines use a laser to heat the particle matter to its melting point. The final pieces are precise, have superb surface quality, and have mechanical qualities that are almost wrought. When you want to print a small quantity of industrial objects that would be difficult or impossible to construct due to hollow areas, undercuts, difficult angles, and other complications, DMLS printers are advised.
6. Sheet Lamination
Sheet lamination, often known as laminated item fabrication, is one of the less well-known 3D printing techniques (LOM). Due to the layer-by-layer procedure used to bind one sheet of material to another, it is regarded as additive. Ordinary paper was used in early sheet lamination systems, possibly coated with a binding agent or having one sprayed on during the process. Modern techniques switched to coated paper, which streamlined the apparatus. To create a coloured three-dimensional item, coloured paper was occasionally utilised. Other times, coloured inks were applied to the paper. The final portion was typically sliced with a laser or a blade layer by layer. This technique was mostly employed for “look and feel” or prototype proofs of a design. The binding agents gave things created by sheet lamination frequently wood-like characteristics. To make them survive longer, they might be sanded and painted. Depending on the design of the object, this procedure may result in significant material waste. Using heat and/or pressure to bind the layers together, the LOM technique has a tendency to fuse layers (often of paper with a binding agent). Similar to sheet lamination, the final shape was achieved by removing extra material with a laser or cutting blade. Ultrasonic vibrations are one method of sheet lamination that is used to fuse the layers together.
7. Directed Energy Deposition
A metal 3D printing technique called Direct Energy Deposition (DED) creates objects by melting and fusing material as it is being deposited. It is also known as directed light fabrication and 3D laser cladding. DED is typically used to repair and restore broken components rather than creating new ones. A series of 3D printing techniques known as DED concurrently add material and heat. A laser, electron beam, or plasma arc are all examples of heat sources. Wire or metal powder is the materials that are used. Because just a portion of the whole powder is melted and attached to the substrate, powders have poorer deposition efficiency than metal wires. This page describes direct energy deposition’s operation, applications, benefits, and drawbacks. The method involves depositing material, either in the form of metal wire or powder, onto a base or component positioned on a multi-axis arm with typically four or five axes. A heat source, typically a laser, but occasionally an electron beam or plasma arc, melts the material as it is being deposited.
Applications of 3d Printing
Despite the fact that 3D printing has been available for a long time, its use and popularity have increased recently. Although new 3D printing applications are continuously being created, the ones listed below have rapidly gained prominence.
1. Medicine Devlopment
There have been numerous 3D printing applications in the field of medicine during the last few years. They range from medical items like prosthetics to bio printing, which combines biomaterials like cells and growth hormones to produce tissue-like structures that mimic their natural counterparts. Metal orthopedic implants are also created using medical applications of 3D printing. These kinds of implants more easily merge with the patient’s own natural bones and allow them to grow into the implant because 3D printing has the ability to produce porous surfaces.
2. Prototyping
Designing and constructing a product as closely as feasible to the final product delivered is known as production prototyping. A prototype must appear authentic enough for potential users to engage with it and provide feedback. The company can avoid spending a lot of time and money developing a product or service that won’t work in practice if the user’s feedback on the prototype is unfavorable.
Types of prototypes in product design. Prototypes are categorized based on the degree of accuracy needed.
a. Low Fidelity Prototype
In the same way as cardboard mock-ups and paper sketches or consumer products are generated quickly and simply for testing the border concept, these are.
b. High Fidelity prototypes
These have the same look and functionality as the finished item. They are utilised in sectors where the highest level of precision is required and the optimal application of 3D printing is crucial, such as the automotive, robotics, aerospace, and defence sectors given how precisely production parts are cut.
3. Education
More schools are adding 3D printing techniques to their curricula every day. By enabling students to make prototypes without the use of costly tooling, it has the advantage of better preparing them for their future. Students create models they can hold to learn about the applications of 3D printing. Students of graphic design can simply assemble models with intricate functional elements. Science students have the option of making and studying cross-sections of various biological samples, including human body organs. Molecules and chemical compounds can be modelled in three dimensions by chemistry students.
4. Construction
Construction In addition to reducing labour expenses and waste production, 3D printing might make it possible to create intricate or custom objects more quickly and accurately. Additionally, it might make it possible to carry out construction in hostile or hazardous areas where a human crew is unsuitable. Building shelters for victims of disasters using 3D printing 3D-printed bridge Building a Canals
5. Art and Jewelry
Very detailed jewelry designs can be created using 3D printing, then tested for durability and structural integrity. You can identify the weak points in the design and change your design or material before investing in an expensive and time-consuming mould. Each layer of a UV-sensitive resin is photo cured using the vat photo polymerization processes SLA and DLP to create a solid item. Castable resins with a very little amount of leftover ash after burnout can be used in SLA and DLP to create smooth, highly detailed pieces.
Final Remarks
The ability to produce prototype parts rapidly and affordably with 3D printing has advanced significantly in recent years. Waste material can be significantly decreased as compared to subtractive production methods. By employing 3D printing, it is possible to make parts that are lightweight and resistant to high stresses while also producing shapes that would be expensive or difficult to make using more traditional techniques.
The use of 3D printers in high-speed inline manufacturing could one day provide a productive way to produce parts just in time to meet demand or to streamline supply chain management when creating goods in small batches. By providing the relevant CAD or G code file, production may also be readily increased in size or moved to another line. The most recent desktop printers make it possible for engineers to gain familiarity with this rapidly expanding technology with little financial outlay.
