3D printing, also called additive manufacturing, is a process in which an object is made from a three-dimensional CAD file by depositing materials in layers. 3D printing can be used to produce all types of products like aeroplane parts, medical implants, artificial organs, novelty items, toys, sculptures, 3D figurines and much more.
There are several types of 3D printing - stereolithography (SLA), fused deposition modeling (FDM), selective laser sintering (SLS), digital light processing (DLP), multijet fusion (MJF), polyjet, direct metal laser sintering (DMLS), electron beam melting (EBM). Sometimes, rapid prototyping is confused with 3D printing techniques. But rapid prototyping is an application of 3D printing, which involves prototyping a part from a CAD file or better put as 3D printing is the process and rapid prototyping is the end result.
Based on the type of material, durability, surface finish, speed and cost, the 3D printing type is selected.
The process of 3D printing involves three steps:
- 3D modeling software: The object is designed with intricate details in the 3D model using CAD software. The software has the ability to allow for the tiniest, and precision designs. The CAD file is then converted into STL format.
- Slicing the model: Next, the model is sliced into hundreds or thousands of layers with a slicing software and sent off to the 3D printer via USB, WiFi or SD.
- Final process: In a 3D printer, a nozzle moves back and forth while dispensing the material layer-by-layer waiting for a layer to dry before adding the next.
3D printers are extremely flexible, accurate and fast to print rigid materials, and even strong industrial products.
Rapid prototyping is a process of fast fabricating or modeling or assembling a physical part using 3D CAD. The part is then manufactured using additive manufacturing technique or 3D printing. Rapid prototyping is highly beneficial for designers to visualize, design and develop the product before it goes for mass production. There are two types of prototypes - high fidelity where the design matches the projected end product, and low fidelity where the design does not exactly match with the end product.
Rapid manufacturing means the use of software and equipment to accelerate the manufacturing process. It is a broader term that encompasses moulding, CNC machining, vacuum casting, rapid tooling and more. With the help of various 3D printing techniques like selective laser sintering, stereolithography, laser melting, high resolution 3D objects can be created from CAD data.
3D printing offers a range of benefits which include:
Reduced wastage: 3D printing uses only the amount of material required for a particular part, thus making it more economical.
Strong and lightweight part: Plastic which is known best to produce lighter parts is one the widely used material. This is especially beneficial for aerospace and automotive industries that use lighter parts for fuel efficiency.
Better design complexity: 3D printing gives better design freedom to design and print complex geometries without any restrictions.
Speed, flexibility and customization: It is fast without having to create moulds like in the traditional process. Parts can be customized for mass production and printed on demand as the 3D design files are stored in virtual libraries. They can be edited any time saving costs on wastage and inventories.
A lot of industries like aerospace, automotive, education, robotics, fashion, medical, electronics, etc are using 3D printing.
3D printing technologies that are revolutionizing the manufacturing process are Fused Deposition Modelling (FDM), SLS, which are highly ideal for plastics and alumide, Stereolithography, Continuous Liquid Interface Production (CLIP), Digital Light Processing (DLP) that use photopolymerisation. Other 3D printing techniques include Electron Beam Melting (EBM), Direct Metal Laser Sintering (DMLS), and more.
Nylon, ABS, resin, polylactic acid or PLA, gold, silver, stainless steel, titanium, ceramics, PET/PETG, high impact polystyrene or HIPS, polycarbonate, polypropylene, PVA, etc. are some of the commonly used 3D printing materials.
Commonly referred to as SLA 3D Printing, stereolithography is an industrial 3D printing process that prints parts with highest details, tighter tolerance and smooth surface finish. This uses a technique called photopolymerisation wherein photosensitive liquid resin is hardened using a high-powered UV laser that creates the desired 3D shapes or objects.
SLA is an ideal choice for producing accurate and finely detailed parts with ultimate precision and water tightness and is adaptable with a wide range of materials.
SLA applications: Medical industry for making custom ear products, entertainment industry for video games, bespoke costumes and even special effects, digital dentistry, in education for exposing students to STEM concepts, and more.
SLS 3D printing provides high design freedom and accuracy, and produces parts with good isotropic mechanical properties and excellent tensile strength. The commonly used materials for SLS parts are polyamide, aluminum filled nylon (aluminide), glass-filled nylon, and carbon-filled nylon.
In the SLS process, a high-powered laser sinters the particles of polymer powder into a solid 3D model. SLS is used for rapid tooling, jigs and fixtures, moulds & casting patterns, transparent covers, optics, and more.
In Fused Deposition Modeling (FDM) 3D printing, also known as material extrusion, the printer melts material which is mostly plastic and extrudes it from a nozzle in single layers. Multiple layers of molten plastic are then fused to form 3D printed plastic parts. The parts from this plastic 3D printing are tough and rigid, low weight and high strength.
On the benefits side, FDM is economical, easy to operate with no chemical post-processing, supports plastics that are environment-friendly and produce parts that have complex geometries.
PolyJet 3D printing is ideal for precision prototypes and products that are smooth, accurate, intricate details, complex geometries and delicate features. Just like how inkjet printers jet ink drops onto papers for printing documents, PolyJet works by jetting liquid photopolymer onto a tray. These layers are then cured with UV light for producing 3D models.
This could be put as MultiJet meaning, with multiple jetting heads PolyJet printers can even jet photopolymers of different colours to print multi-coloured objects easily. It supports a wide range of materials and is used across all industries. For example, in the healthcare sector for joint replacements, orthodontic appliances, prosthetic limbs and more.
Metal 3D printing is an additive printing process that uses powdered metals and requires no contact tools and is managed entirely via laser beams. Here, a design is made on CAD and converted into .STL format. The design is then sliced and passed into the 3D printer. High-powered lasers are then passed to bind together the powder particles to form the 3D metal part. In the process, even layers of metallic powder are distributed.
Metal 3D printing is a type of additive printing based on laser technology that uses powdered metals. Some of the benefits of metal 3D printing include strong and robust finish, easy to customize or modify designs, ability to make ultra-complex parts and cavities which are impossible in traditional manufacturing and cost-effectiveness.
The most common types of metal 3D printing are Powder Bed Fusion which include Selective Laser Melting (SLM) and Electron Beam Melting (EBM), Direct Energy Deposition or also called Laser Material Deposition, Electron Beam Additive Manufacturing, Binder Jetting, Bound Powder Extrusion to name a few.