3D Printing – Manufacturing Made Simple
Saravana P presents an overview of 3D printing – currently the world’s fastest growing technology – and its applications.
Next Big Innovation Labs
3D Printing is a form of additive manufacturing where each layer is added one above another to form a 3 dimensional model. It totally eliminates traditional subtractive manufacturing like cutting, bending and drilling processes.
3D printing began in 1980, simplifying the initial stages of product development- prototyping. This gave 3D printing the name Rapid Prototyping. This technology revolutionised the prototyping processes, thanks to the innumerable advantages it offers. Tremendous improvements in additive manufacturing over the years have made 3D printing applicable in various fields. Materials like thermoplastics and metals were used in the manufacturing applications, while ceramics, food and fabric were used in lifestyle applications.
Technological revolution gradually upgraded all industrial processes, similarly the 3D printing technology also turned into a game changer for manufacturing. 3D printers are generally categorised based on their working mechanisms:
- Stereo lithography
- Digital Light Processing
- Fused Filament Fabrication
- Selective Laser Sintering
- Selective Laser Melting
- Electron Beam Melting, and
- Laminated Objects Manufacturing.
The 3D printing process starts with a solid 3D model file that can be modelled with any of the Computer Aided Design (CAD) Software commonly available. The CAD files are saved in a printable format (most commonly .stl and .obj formats). If you are working on a non-parametric object, special software pre-processing is required to get it into a printable model.
To print the 3D model using a 3D printer, the model should be sliced into horizontal layers depending on the required resolution and later converted into G-Codes (language understood by most CNC machines). This process is carried out by the various types of slicing software available. One can also get designs printed using paid online services, and they also provide the flexibility of choosing the printers, materials and even colours.
Stereo lithography (SLA)
This methodology is the oldest form of 3D printing which is still being used now. It converts liquid plastic resins into a solid model. A laser beam is used to cure each layer. The resin cures in micro seconds giving enough time for the next layer to adhere on it.
Digital Light Processing (DLP)
DLP is another 3D printing process which works similar to SLA. Both use Photopolymer resins and light as the curing medium. The major difference between them is, DLP uses conventional sources of lights (like arc lamp or UV) whereas SLA uses laser for curing. This process gives higher resolution with lower material consumption.
Fused Filament Fabrication/Fused Filament Fabrication (FFF/FDM)
The most commonly used 3D printing process is Fused Filament Fabrication/Fused Deposition Modelling (FFF/FDM). This process has gained wide recognition due to the ease of manufacturing/assembling these machines and availability of raw materials in the form of filaments. The FDM printers are widely available as desktop printers which makes it the most feasible and user friendly among all others.
FDM machine uses materials like PLA (Polylactic Acid) which is also biodegradable in nature, and ABS (Acrylonitrile Butadiene Styrene) in common and PVA, Nylon, etc., for special purpose applications.
Selective Laser Sintering (SLS)
SLS printers use raw material in the form of powder which is then sintered by a laser beam. The printed parts do not require any support structure to hold it in place like FDM and Stereo lithography. The un-sintered powder acts as a supporting structure and holds the overhanging layers in place.
Selective Laser Melting (SLM)
The SLM process is mainly used for metal printing. Here the metal powder is melted using a high-power laser beams. The beam fuses and melts the powder to form the solid object. As like all process, this technique also uses 3D model file as the base file and converts it into solid model. This method is applied to produce high quality parts with thin walls. More specifically SLM printers are widely used in aerospace applications to produce light weight and high precision parts.
Electron Beam Melting (EBM)
EBM is another type of process used for manufacturing metal. The difference between EBM and SLM is, instead of a laser beam EBM uses an electron beams to fuse the layers. These two processes are usually conducted at a maximum operating temperature of around 1000?C which is required to fuse materials like Titanium, Inconel 625 and other high-end metals suitable for these processes.
Laminated Objects Manufacturing (LOM)
In LOM, a very thin layer like paper, plastic or metal laminates coated with adhesives are used. The layers are fused together by applying high pressure and moderate heat which in turn melts the adhesive present in the thin sheets. It is then cut to a required shape with a knife or laser which is controlled using suitable software. The LOM is not widely used though the cost for production is less due to low cost materials.
Start-ups all over the world consider 3D printing as their biggest boon. The reason behind this scenario is that, traditional manufacturers are hesitant to undertake projects that have a low order quantity. Every new order requires the manufacturer to vary machinery and tools. Start-ups cannot afford the high cost of tools and machinery for their prototypes, this leads them to the 3D printers.
3D printing has a wide range of applications, ranging from Aerospace to Healthcare. Everyone might wonder how manufacturing can be made simple!
Aerospace and automobile industries use this technology for prototyping, tooling and part manufacturing to reduce the expensive CNC processes. The printed high performance thermoplastic material, weigh less and serves as good insulators. In some cases, 3D printed model is used to test, find the design issues and resolve them before final production.
One of the major applications of 3D printing is “Idea to Product”. Commercial product manufacturers have already started manufacturing their concepts into single or multi-functional prototypes. This aids them to research and analyse the extreme properties of materials in-house without outsourcing. It also helps them to rework on their designs before investing on mass product manufacturing.
Bringing consumer grade electronics to the market solely depends on its design, ergonomics and its functionality. 3D printing technology helps them to figure out the part fit and tight tolerances. Prototypes that are manufactured from highly production grade plastics help to ensure the concept, finishing, realistic appearance and endurance of the product.
3D printing of architectural models allows us to combine the graphical 3D modelling and virtual appearance as real physical scaled down model. This helps architects to showcase their design ideas to their clients. It also reduces design time and allows them to plan their future stages. The design concepts can be re-worked based on their client’s requirements.
The world’s fastest growing technology has also stormed on the textile and fashion sectors which aids in designing, printing and styling. Various industries provide printable materials that are flexible and can be printed into fabric.
Footwear industries also incorporated 3D printing to implement prototypes with high strength and flexible materials. These can be adopted for sports applications and customised footwear.
Prosthetics for the differently abled can be created by scanning and printing parts that are designed specifically for the patient. The parts that are printed can be made using a range of materials depending on the strength and flexibility required. The printed prosthetics are also less bulky and more comfortable since they are made customer specific.
Defence industries are rapidly increasing the use of 3D printing to make parts and tools for military equipment. The navy is conducting research in this technology to build on-board spares and tools. The parts to be printed are saved in their printable format and put on print even at remote locations. This technology is also being worked on in space expeditions where they have no access to manufacturing machines.
3D printing is implemented in civil construction by various private organisations to build commercial, industrial and public structures. Implementing 3D printing provides variety of advantages in order to reduce labour cost, increased accuracy and faster construction. The methods currently used are extrusion based (quick setting concrete), powder bonding and additive welding.
Medical and healthcare industries have started making products using this technology. Bio-inks are being researched upon all over the world with a vision of printing with living cells. The research uses this technology to print various tissues, organs, bones, cartilage or stem cells. They have also found various uses of 3D printing in dental applications.
3D printing has a promising future in the days to come. It can be used in numerous applications to make life easier. Desktop printers have made 3D printing a feasible technology tucked in the corner of your workspace.
Saravana P is a Sr Design Engineer, Next Big Innovation Labs, a 3D Bioprinting Company based in Bangalore.