Additive VS Subtractive Manufacturing
OverviewAdditive and subtractive manufacturing both function via CAD (Computer Aided Design) software. Both forms of manufacturing can be highly accurate and used for intricate designs for various industries and uses. Both have their niches and benefits for specific aims, which we will delve into below.
Additive ManufacturingThe world of additive manufacturing is ruled by 3D printers. 3D, much like the name suggests, operate by printing layers of material, rather than detracting from a pre-existing object. This function is called fused depositional modelling and works by the machine repeatedly depositing over the same area to build from the base upwards to create the final model. So, although it is called a 3D printer, it actually prints each layer in 2D cross-sectional layers which are essentially stacked upon one another until the desired design has been produced..
Normal printers use either powder or ink to create their marks on paper but of course these substances would not suffice in building a 3D design. In most 3D printing, each layer is born of molten thermoplastic and then fused together either using adhesive or ultraviolet light. Thermoplastics are a type of plastic whose form depends on their temperature – when heated, they become liquid and when cool they return to solid form. This of course does mean that during the process of 3D printing, the machine must wait for each layer to cool before depositing the next, in order to preserve the integrity of the shape.
While the most common material used with 3D printers is plastic, some also function using metal. These printers still function with the same layer-by-layer process of 2D sections; however they use blankets of metal powders in place of their plastic material counterparts.
Subtractive manufacturingSubtractive manufacturing begins with a block of material and cuts away at it in order to reveal and create the desired part. CNC machines dominate the subtractive manufacturing realm and come in myriad forms to cover an array of demands. Like 3D manufacturing, CNC machining can be used with plastic and metal but works with them in their solid raw forms.
CNC machines work in various ways, they can either have manoeuvring and rotating tools being introduced to a still material which is held in place or the object itself can be rotated by the machine. Again, this is project dependent. CNC machines can work on a variety of materials from metal and plastic to wood and come in all shapes and sizes, learn more about types of CNC machines and their functions here.