What is 3D Printing? Types of 3D Printing with Examples

A decade and a half back, kids used to get fascinated when coloured print-outs used to come out from laser printers and get deposited at the tray.  Right from their favourite cartoon characters to star footballer, WWE fighters to WWF animal posters, they got it all printed with high enthusiasm. Cut to the present – kids nowadays are creating 3D models of their superheroes, celebrities and what not with the help of a 3D printing machine. Apparently, 3D printing has revolutionized many segments including education, medical science, architecture, arts & crafts, automobile, robotics, etc.

3D Printing technology is on a growth spree in every industrial vertical. Alongside, there’s also surge of Artificial Intelligence (AI), Blockchain technology, which are having a huge impact on today’s economy and existing production systems. However, combining 3D Printing technology with AI will lead to unimaginable possibilities. AI when integrated with 3D printing technologies increases the performance of a 3D printer by reducing the risk of error and facilitating automated production. Infact, many Startups are integrating AI into a 3D printing product or service and are being benefitted. 

What is 3D Printing?

3D Printing in layman’s language is the process of creating three dimensional objects from a digital file through an additive process. Hence, it is also often termed as Additive Manufacturing. In an additive process an object is created by laying down successive layers of material until the object shapes up properly. Each of these layers can be seen as a thinly sliced cross-section of the object.

3D printing enables us to produce complex shapes and structures using less material than traditional manufacturing methods. 3D Printing’s the precision, repeatability, and material range have increased to the point that some of these printing processes are considered viable as an industrial production technology are widely being used. Rapid prototyping is best done through 3D printing, as it suits best to create complex and bespoke items in relatively less time as compared to conventional manufacturing processes.

Primarily there are three types of 3D Printing technology that’s currently in use, they are as follow :

  • Sintering – under this specific technology the material is heated, but not to the point of melting, in order to create high resolution items. Metal powder is used for direct metal laser sintering while thermoplastic powders are mostly used for selective laser sintering.
  • Melting – this particular method of 3D printing includes powder bed fusion, electron beam melting and direct energy deposition. It use lasers, electric arcs or electron beams to print objects by melting the materials together.
  • Stereolithography – this 3D printing uses photopolymerization to create parts. It uses the correct light source to interact with the material in a selective manner to cure and solidify a cross-section of the object in thin layers.

How long does 3D Printing take?

Executing a 3D printing work depends on several factors, including the size of the part and the settings used for printing. The quality of the finished part is also important when determining printing time as higher quality items take longer to produce. 3D printing can take anything from a few minutes to several hours or days, which largely depends on speed, resolution and the volume of material used.

Types of 3D Printing 

As per ISO/ASTM 52900:2015, which aims to provide a basic understanding of the fundamental principles for additive manufacturing processes, 3D printing can be categorized into seven groups and they are as follows :

  1. Binder Jetting – Layers of powdered material such as metal, polymer sand or ceramic are deposited in thin layers, after which drops of adhesive are deposited by the print head to bind the particles together. Through this function, layer by layer formation of parts happen. Binder jetting is used for a variety of applications such as, 3D metal printing, full colour prototypes and large scale ceramic moulds.
  1. Material Extrusion – This is also known as FDM (Fused Deposition Modeling) This type uses a spool of filament which is fed to an extrusion head with a heated nozzle. The extrusion head heats, softens and lays down the heated material at already set locations, where it cools to create a layer of material, thereafter the next layer is created likewise. This is cost-effective process with short lead time but also has a low dimensional accuracy and often requires post processing to create a smooth finish. 
  1. Material Jetting – This functions almost like an inkjet printing except, rather than laying down ink on a page, it deposits layers of liquefied material from one or more print heads. The layers are then cured before the process begins again for the successive layer. Material jetting can be made from a water soluble material that can be washed away once the build is complete. This process of printing is one of the most expensive 3D printing methods, and the parts tend to be brittle and degrades over time. 
  1. Direct Energy Deposition – This uses focussed thermal energy such as electric arc, laser or electron beam to fuse wire or powder feedstock as it is deposited. The process is traversed horizontally to build a layer, which are stacked vertically to create a part. This process can be used with metals, ceramics and polymers.
  1. Powder Bed Fusion – In this process, thermal energy selectively fuses areas of a powder bed to form layer, and layers are built upon each other to create a structure. This covers both sintering and melting processes and the final outcome is a volume containing one or more fused parts surrounded by unaffected powder.
  1. Sheet Lamination – This process are of two types, laminated object manufacturing (LOM) and ultrasonic additive manufacturing (UAM). While the former uses alternate layers of material and adhesive to create items with visual and aesthetic appeal, the later joins thin sheets of metal via ultrasonic welding. UAM is a low temperature, low energy process that can be used with aluminium, stainless steel and titanium.
  1. VAT Polymerization – This again consists of two techniques, stereolithography (SLA) and digital light processing (DLP). Both the techniques create parts layer-by-layer through the use of a light to selectively cure liquid resin in a vat. This technique is ideal for parts with a high level of dimensional accuracy, to create intricate details with smooth finish, making them perfect for prototype production.

How big is 3D Printing Industry?

Adoption of 3D printing is fast spreading among industries, and for those who are yet to integrate additive manufacturing somewhere in their supply chain are now part of an ever-shrinking minority. Though 3D printing started for prototyping and one-off manufacturing in its early stages has now been transformed into a full-fledged manufacturing technology contributing to fast turn-around-time and lower cost of production. Most of the current demand for 3D printing is industrial in nature. 

As per Statista, the global market for 3D printing products and services was valued at around 12.6 billion USD in 2020. The industry is expected to grow at a CAGR of around 17% between 2020 and 2023. As it evolves, 3D printing technology is destined to transform almost every major industry and change the way we live, work, and play in the future. General Electric has the most 3D printing patents in the United States.

How does a 3D Printing work?

3D printing comes under the additive manufacturing family and uses similar methods as that of a traditional inkjet printer, but in 3D. It takes a combination of top-of-the-line software, powder like materials and precision tools to create a 3D object from scratch. Below are a few of the main steps 3D printers take to bring ideas to life.

  • 3D Modelling Software – Before initiating any 3D printing process, 3D modelling is must. To maximize precision all objects have to be designed in a 3D modelling software. Some designs are too intricate and detailed for traditional manufacturing methods. But these all can be achieved through a CAD software effectively. Modelling allows printers to customize their product down to every minute detail. The software’s ability to allow for precision designs is why 3D printing is being hailed as a true game changer in many industries. This modelling software is especially important to an industry, like dentistry, where labs are using 3D software to design teeth aligners that precisely fit to an individual patient. It’s also vital to the space industry, where they use the software to design some of the most intricate parts of a spaceship. Some of the 3D modelling software that one can try hands on are Morphi, BlocksCAD, Leopoly, 3D Slash, TinkerCAD, Sculptris etc.
  • Slicing the Model – Once a model is created, it’s sliced. Since 3D printers cannot conceptualize the concept of three-dimensions like us, operator needs to slice the model into layers, so that the printer can create the final product. Slicing software takes scans of each layer of a model and will instruct the printer how to move in order to recreate that layer. Slicers also tell 3D printers where to fill a model. This fill gives a 3D printed object internal lattices and columns that help shape and strengthen the object. Once the model is sliced, it’s sent off to the 3D printer for the actual printing process. There are several slicer software available to carry out this function of some sort of middleman operation between a 3D model and a Printer. Cura, IdeaMaker, KISSlicer, OctoPrint, Slic3r, AstroPrint, Simplify3D, IceSL are some of the slicer software which are best for all level of designer, be it beginner or Pro.
  • 3D Printing Process – When the modelling and slicing of a 3D object is completed, it’s time for the 3D printer to be in action. The printer acts generally the same as a traditional inkjet printer in the direct 3D printing process, where a nozzle moves back-and-forth while dispensing a wax or plastic like polymer layer-after-layer, waiting for that layer to dry, then adding the next level. It essentially adds hundreds or thousands of 2D prints on top of one another to make a 3D object. There are a variety of different materials that a printer uses in order to recreate an object to the best of its abilities. Here are some of them :
  • Acrylonitrile butadiene styrene (ABS)
  • Carbon Fibre Filaments
  • Conductive Filaments
  • Flexible Filaments
  • Metal Filaments 
  • Wood Filaments

There are various types of 3D printing depending on the size, detail and scope of a project. Each different type of printer will vary slightly on how an object gets printed. Fused Deposition Modelling (FDM) is probably the most widely used form of 3D printing, while Stereolithography (SLA) is a fast prototyping printing that is best suited for printing in intricate detail. The printer uses an UV laser to craft the objects within hours. 

Examples of 3D Printing

In spite of being around for over a decade, the surge for 3D printing’s popularity has happened in recent years. New 3D printing applications are constantly being developed to suit mankind in a cost effective manner. Some of the popular applications of 3D printing technologies are discussed below according to the categories.

1. Education – more and more schools and colleges are incorporating 3D printing methods into their curriculums. It helps students to understand nuances of several complex structures by allowing them to create prototypes without the need for expensive tooling. This also helps them be future ready. They are now commonly found in classrooms and public libraries. Students learn about a variety of 3D printing applications by exploring design, engineering, and architectural principles. They are able to duplicate museum items like fossils and historical artefacts to study in the classroom without the possibility of damaging delicate collections.

2. Prototyping and Manufacturing – the main objective for 3D printing was to create prototypes. With a traditional injection-moulded prototype it might cost hundreds of thousands of dollars and take weeks to produce a single mould, whereas 3D printing is just a click away. The automotive and aerospace industries are just 2 industries involved in mass production is taking advantage of advances in 3D printing technologies. These days 3D printing technology is used to create “agile tooling”. Tooling used in manufacturing processes such as hydro-forming, stamping, and injection moulding is designed by modular means, enabling quick prototyping and responses to tooling and fixture needs.

3. Medical field – The medical world has been benefitted tremendously by 3D printing technology. And its versatility in creating prosthetics is mind-boggling. Bio-printing through 3D printing technology even helps in creating artificial organs quite easily, helping solve organ failure issues in patients faster. 3D printed tissues have been developed for pharmaceutical testing as a cost effective and ethical means of helping identify the side effects of drugs and validating safe dosages. 

4. Architecture and Construction – 3D printing is now majorly in use for construction work, mainly for per-fabricated buildings which are later assembled at construction site. 3D printing in construction has a wide array of applications in the private, commercial, industrial and public sectors. Advantages of these technologies include allowing more complexity and accuracy, faster construction, lower labour costs, and less waste. 3D printing is used to produce architectural scale models, enabling a faster turnaround of the scale model and increasing the overall speed and complexity of the objects produced.

5. Art and Craft – 3D printing has unexpectedly become popular in creating arts, jewellery & novelty items. 3D printing technology has served to inspire artists all over the world. With metal 3D printing especially, artists now create beautiful intricate pieces. It is widely used to make props for movies. Home decorative items can also be printed in order to give a facelift to your house. 

With increasing popularity of 3D printing, there should be more and more technicians and designers trained to execute projects with perfection. Becoming a pro and mastering the art of 3D printing can a great career option. Though it isn’t a rocket science, but learning few model designing software application along with slicer software can be of great use. 

Gunaseelan Murugesan
Author | Website

Experienced Project Engineer with a demonstrated history of working in the field of Product Design & Development industry in Mechanical Engineering. Skilled in 3D Printing and Re engineering Technologies with CATIA V5 , Materials Science, Finite Element Analysis (FEA), Mimics, ANSYS Workbench and Casting Simulation software. Strong engineering professional with a Master’s Degree focused in Industrial Metallurgy from PSG College of Technology, Coimbatore.

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