Additive manufacturing (AM) is a process whereby three dimensional objects are created layer-by-layer using 3D object scanners or computer aided design. As the industrial equivalent of 3D printing, additive manufacturing removes the need for machining or other methods of removing excess material as the process only deposits necessary materials.
Ideal for creating complex geometric shapes, additive manufacturing is suited for making bespoke parts and prototypes, while the computer aided design allows for any design changes to be effected quickly and efficiently.
Additive manufacturing offers cost reductions for high-value parts due to the lack of material wastage and can also reduce lead times. In addition, this manufacturing process can improve part strength and durability as items can be created as one solid object rather than being assembled from multiple parts.
There are several additive manufacturing processes, which are all governed by their own standards and quality control requirements. These processes include laser metal deposition, which TWI has been developing for over ten years and has been used for the repair of high value parts for aerospace and the military, selective laser melting, powder bed fusion, and arc-based additive manufacturing.
As a versatile manufacturing technique, AM is widely used in industries including aerospace, automotive, and medical, and is suitable for use with a number of different materials.
The most common materials used are thermoplastic polymers, while metals and metal alloys, ceramics, and biochemicals are also suitable for additive manufacturing processes. Additive manufacturing technologies can be broadly divided into three types:
Sintering
This process heats the material without liquefying it to build complex, high resolution parts from powdered material.Direct metal laser sintering (DMLS) works with metal powders, whereas selective laser sintering heats thermoplastic powders using a laser to join the particles.
Melting
A number of additive manufacturing technology types melt the materials, such as electron beam melting, which uses electron beams to melt powders in order to print parts.
Stereolithography
The third broad type of AM printing solutions use a process called photopolymerisation for part production. This involves firing an ultraviolet laser into a vat of photopolymer resin to create torque-resistant, high performance ceramic parts that can withstand extreme temperatures.
For more information on AM, visit our 'what is additive manufacturing' webpage.