By Lu
Issue 1 January 10, 2017

Computer hobbyists are pursuing personal 3D printers to make plastic toys and utility items at homes and offices. They may not know that 3D printing is classified under a technology properly called ‘Additive Manufacturing’, which will revolutionize the way products are made.

Here are some basic principles and applications of additive manufacturing.

What is Additive Manufacturing (AM)?

Additive manufacturing (AM) describes a process to build a three dimensional object by “Adding” material layer by layer until the object is finished.

Additive manufacturing is now commonly referred as 3D printing, which is the prominent technology used in additive manufacturing processes.

How AM works

The first step is to carry out Computer Aided Design (CAD) to convert the physical shape and dimension into digital data (3D model) to drive the AM machine. CAD is created by 3D modeling software or with a 3D scanner.

The 3D model is then ‘sliced’ by printer software into hundreds of horizontal layers. Once the model is fed into the printer and get started, the object will be      printed layer by layer to build up the three dimensional object.

The more complicated part of the manufacturing process is the variety of methods used by different types of AM machines in forming the whole object from layers. The methods also depend on the initial state of materials (before printing), coming in the forms of solid, liquid and powder.

Example of AM Machine: Fused Deposition Model (FDM)

This is one of the popular methods (often used by home 3D printers) to form objects from a thermoplastic material. The material changes to a liquid on heating and turns to a solid form when it cools down.

Thermoplastic material filament is unwound from a coil and fed to a nozzle which can turn the flow on and off. The nozzle is heated to melt the material and can be moved in horizontal and vertical directions following the shapes of objects under the control of printer software.

The plastic filament is injected by the nozzle to the platform, melts and then hardens immediately into solid to form layers into cross sections. These sections are traced by the nozzle in shapes programmed in the 3D model.

Applications in Manufacturing: Rapid Prototyping

Additive manufacturing machines and materials were developed in 1980s. One of the early applications in AM was to produce prototypes. Prototypes are experimental versions of finished products for research and manufacturing.

Before AM, designers had to spend time in preparing drawings and making different components, and assembling them together. The process needs to be repeated if modifications are required on some components.

AM can simplify and speed up the prototyping process. Designers can start immediately on the Computer Aided Design (CAD) works, create the 3D models and build up early prototypes which have less components and fewer assembly. Then make modifications efficiently by changing the 3D model data and running the AM machine again.

More Applications: Small to medium scale production

AM technology has been developing rapidly since 1980s. AM machines become more powerful and printing materials are improved. By using advanced software, designers can create 3D models easily.

AM is now used by many large companies to produce not only prototypes, but also large quantities of high performance finished products.

Unlike most traditional manufacturing techniques, AM forms objects by adding/building matter up, rather than removing. For example, conventional machine tooling is a ‘Subtractive technology’ where unnecessary material is removed layer by layer to form a desired solid form. AM can save time and materials in small to medium scale production.

Application in Health care and aircrafts

The health care industry is one of the pioneers in using AM. Products such as dental crowns and bridges, hearing aids and orthopaedic implants have been produced by AM in batches. By changing data in 3D models, AM and 3D printers can produce customized products quite easily to fit different sizes and shapes of the body parts of patients.

General Electric (GE) announced in 2016 that they installed a 3D printing factory in Alabama to produce up to 40,000 fuel nozzles a year for the new jet engine. The nozzles will be printed in a single piece, instead of being made up from 20 different parts. Using different mix of powder materials in printing process produces lighter and more durable fuel nozzles than from traditional manufacturing process.

Next revolution in manufacturing

Traditional mass manufacturing can produce large quantities of standardized products cheaply. It remains as the dominant form of production in many industries.

By contrast, additive manufacture/3D printing can design and produce more complex and personalized products on demand basis, which are what consumers want today. It will create a whole new product category and bring a new era in manufacturing.