3D printing

Definition

Basic kinds

• Stereolithography (SLA): A technology using liquid photopolymer resins that are cured layer by layer with a UV laser.
• Fused deposition modelling (FDM): A popular method in which molten filament (e.g. PLA, ABS) is deposited layer by layer on a working platform.
• Selective Laser Sintering (SLS): A technique that uses a laser to sinter a powder, usually polymer or metal, to form layers of an object.
• Printing with metallic powders (SLM/DMLS): The process of creating metal objects by melting metal powders using a laser.

Main roles

• automotive – prototypes, spare parts, dynamic components, production support tools
• construction – finishing elements, entire buildings
• food industry – finishing elements for cakes, pancakes, chocolate elements, meat pastes
• aerospace industry – structural components, spare parts
• power industry – working components
• foundry – casting moulds
• dentistry – tooth crowns, denture models
• medicine – bioprostheses, tissues, medical instruments, implants
• fashion industry – accessories, jewellery, shoes, clothing, accessories

Basic elements

• Printhead: The element responsible for applying the material layer by layer. Depending on the technology, the head can be equipped with a nozzle for molten filament (FDM) or a laser for curing resins (SLA) and metallic powders (SLM/DMLS).
• Working platform: The surface on which the object is being built. The platform can be heated to prevent deformation and ensure better adhesion of the first layers of material.
• Material feed system: A mechanism that delivers filament, resin, or powder to the printhead. In FDM printers, the system usually uses rollers. In SLA and SLS printers, the material is fed from a container or tray.
• Modelling and slicing software: CAD software enables the creation of digital 3D models, which are then transformed into a file for printing by slicer software that divides the model into layers and generates a path for the printhead.
• Cooling and ventilation system: Components responsible for maintaining the proper temperature of the printer and material, which affects the quality of printing and prevents parts from overheating.
• Calibration and sensor systems: Calibration systems ensure precise positioning of the print head and working platform, while sensors monitor temperature, material level, and other parameters to ensure that the printing process is correct.

Mechanism of action

• 3D model creation: The object is designed using CAD software and transformed into a digital model, which is then saved in STL or other 3D printer–compatible format.
• Slicing and path generation: The slicer software divides the model into layers and generates instructions for the printer, specifying the paths along which the printhead should move.
• Heating and preparing the material: Depending on the technology, the material (filament, resin, powder) is prepared for the printing process by being heated to the appropriate temperature or properly prepared in a tray.
• Application of material: The printer applies the material layer by layer according to the instructions generated by the slicer software. Each layer is applied exactly on top of the previous one, gradually creating a three-dimensional object.
• Cooling and curing: Each layer of material is cooled or cured to prevent deformation and ensure the durability of the structure. In technologies such as SLA and SLS, the process is done with a laser or UV source.
• Post-processing: After printing, the object may require additional work, such as removing supports, smoothing the surface, and painting or otherwise finishing the surface.
• Quality control: The object is checked for dimensions, quality of finish, and any defects to make sure it meets design requirements.