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prothermo@prothermo.hu Additive manufacturing
Additive manufacturing is a process in which objects are built by depositing thin layers — as opposed to traditional, subtractive machining, in which excess material is removed from a larger blank and what remains becomes the finished product.
One of the best-known additive tools is the 3D printer, which can produce solid objects and products from a computer-generated digital file. Additive processes are used to manufacture the product: progressive material layers are stacked on top of one another to create the desired shape, where each layer can essentially be regarded as a cross-section of the product.
3D printing differs significantly from other, typically subtractive, manufacturing processes because it involves adding material instead of removing it. Thanks to this, complex shapes can also be produced with less material.
The technology was first introduced at the end of the 1980s and was initially used in rapid prototyping for the aerospace and automotive industries. Charles Hull, who later helped found 3D Systems, was the first to file a patent for a stereolithography (SLA) framework. This led to the first major breakthrough in 1988, when the first SLA-technology printer was sold. By the mid-1990s there were many organisations involved in 3D printing, working on the processes and technologies still in use today.
Since its beginnings, 3D-printer technology has advanced enormously — in speed, in versatility, and in the variety and surface quality of printable materials. Printer development continues, and 3D printing is becoming widespread in every field.
Short technical description of process types
| Type | Description | Material |
|---|---|---|
| FDM / FFF | Thermoplastic, extrudable materials are fed into the printer as filament; the print head melts them onto the surface. | plastics |
| LDM | A plastic mass is conveyed by an extruder; once it solidifies, the layers are stacked on top of one another. | porcelain and clay slips |
| SLS | Polyamide powder is spread layer by layer over the work surface and fused by one or more lasers. The advantage is uniform mechanical properties. | polyamides |
| Object / PolyJet | Nozzles deposit droplets of liquid polymer onto the surface, then cure them with UV light. | polymers in RAL colours |
| DMLS | Metal powder is melted layer by layer by a laser in a selective protective-gas environment. | various specialty alloys |
| LCM | A stereolithography process based on photopolymerisation, using special nano-sized ceramic material with custom sintering. | zirconia and alumina, biocompatible calcium phosphate |
Heat treatment in additive technologies
Depending on which printing process was used — powder-based (e.g. SLS, DMLS) or plastic clay (LDM) — the final stage always ends with firing. For technical ceramics, removal of binders by drying and stress relief may precede the final sintering. Especially with metals and special ceramic materials, the use of a protective gas may be necessary, requiring appropriately equipped furnaces. Certain additive manufacturing processes require dedicated equipment.
Industrial 3D printers have opened new avenues in every stage of automotive manufacturing — from functional prototyping, design and tooling to series part production; the automotive industry is a pioneer in 3D-printing process and use.
Prothermo Hofmann offers solutions for the stress relief and sintering of 3D-printed parts as well. Request a quote from our company.