Additive manufacturing (AM) is a generic term used to refer to all processes that offer a cost-effective and fast way to fabricate prototypes and models, as well as finished products. In additive manufacturing, the component is manufactured by adding the material layer by layer.
The term 3D printing is often used as a synonym for additive manufacturing. Additive manufacturing is a professional production process that is the opposite of conventional machining methods. In the case of machining production methods, for example, the model is worked out of a solid block of material, for example by milling, turning or eroding. Whereas in additive manufacturing, the model is built up layer by layer using the materials. Materials may include different metals, plastics or composites. At first, additive manufacturing was used in rapid prototyping, that is in the production of prototypes in industry.
Advantages of additive manufacturing
Conventional production methods, such as milling, drilling or turning often reaches its limits. Some designs cannot be fabricated using conventional technologies. Additive manufacturing enables a design-driven manufacturing process. As a consequence, designs are no longer determined by the manufacturing method but vice versa. With additive manufacturing, even very complex models can be produced, which nevertheless are extremely durable.
Features/Benefits of additive manufacturing
- Tool-less production – no tools are needed to produce components, and as a consequence the one-off costs are almost non-existent.
- Comprehensive design freedom – even complex models can be manufactured
- Flexibility – on-site and on-demand production
- Scalability – serial or one-off production
- Shorten product development and time-to-market
- Opportunity to make ongoing adjustments, even during ongoing serial production
- Manufacture of products on a microscopic scale (for example in medical or electrical engineering)
- High quality and cost efficiency
- Saving of resources
- Geographically independent (no large production sites or large tools needed)
- Customizability of products – products can be adapted to customer demands at no additional cost
Application in 3D printing
The basis for additive manufacturing is a CAD file (Computer Aided Design) containing digital design data.
3D printing applications are very diverse. Here’s a brief overview of the most important areas:
- Serial production
- Educational institutions
- Tool and device construction
- Mechanical engineering
Additive manufacturing process
The principle of additive manufacturing is a step-by-step design in which the material is applied layer by layer. The structure varies depending on the selected method and materials.
Fused filament fabrication
Fused filament fabrication (FFF), also known as fused deposition modeling (FDM), uses molten plastic wire or plastic (especially ABS or PLA) to print. The added material is melted by a heated extruder and applied to a heated bed. The workpiece is made line by line and layer by layer, with the next level being applied only when the previous layer has solidified. This process has the largest possible workable range of materials.
The EVO-lizer 3D printer also uses the FFF process for 3D printing. The following video explains the process of melt stratification using the EVO-tech 3D printer.
3D powder printing
Different materials are suitable for 3D printing with powder. Primarily plastic or plaster is used but glass, ceramics or other powdery materials can be used too. A 3D printer with printheads works in a similar way to a conventional inkjet printer. The printheads apply liquid glue to a powder layer in small quantities. The powdery substances harden and stick the layers of the workpiece together. Thus, creating a model, layer by layer.
Selective laser melting (SLM)
With selective laser melting, materials are not connected by a binder but are fused by means of a high-power laser. Workpieces made of metal can be produced using this process.
Electron-beam additive manufacturing
This method is similar to selective laser melting, where an electron beam provides the energy source instead of a laser.
In this manufacturing process, models are built in a tank filled with liquid photopolymer. A laser projects the layers of the model onto the surface. The liquid photopolymer solidifies after a certain exposure time, forms the first layer and connects to the underlying print bed. The print bed is subsequently lowered and the next layer is built.
Digital light processing (DLP)
The operation is similar to stereolithography, however a DLP projector is used as a light source instead.
Multi-jet modeling (MJM), polyjet printing
MJM is a hybrid of stereolithography and traditional 2D printing. A liquid plastic is applied to a platform and cured immediately with a light source built into a push button. This process is very detailed.
Film transfer imaging (FTI)
FTI works similarly to the MJM process. Here a transport film is used to apply the liquid plastic.