Key component for Fusion Deposition Modelling (FDM) printers is the nozzle.
Diameter of the nozzle is a compromise between deposition rate and printing resolution. Large nozzle improves deposition rate, while high resolution requires small nozzle size.
Another critical issue is the surplus of material that keeps flowing out of the nozzle at the end of each deposition. Normally, a negative pressure is applied in the chamber to suck back the melted material. This leads to cavitation in the material, possible damages at the nozzle and generations of bubbles that are found in the further deposition.
In order to solve these problems the 3D SmartNozzle has an adjustable output hole. Thanks to this feature, adjusting the nozzle to smaller position is possible to print details of the object while deposition of large amount of material can be done using larger nozzle size. Furthermore, the nozzle can be completely closed to prevent any material from leaking.
The nozzle is fabricated by microfabrication MEMS techniques in order to easily obtain exit hole of sub-millimetrical dimensions. MEMS techniques have been used for several years to generate micro mechanical devices that are now part of our every-day life. Silicon wafer monocrystalline is used to fabricate each component through a series of wet plus dry clean-room standard processes.
A batch stable process is finally employed to bond the different components of the nozzle, using technique of modern wafer level packaging. Mobile components are coated of SiN3 to realize an anti-friction coating.
These components are actuated thanks to a pneumatic circuit that can locally reach high pressure. Modulate high pressure applied to actuate the external part of the nozzle, also prevents leakage of material from the joints of the mobile components.
The Main benefits of this solution are listed here:
- Easy processing of plastics that cannot be retro-sucked or/and generate wires.
- The adjustable dimension of the nozzle diameters allows switching outright from precise to rapid deposition.
- MEMS process of silicon material allows to process material with a low expansion coefficient and high resistance.
- Process several nozzles at one time with batch process leads to low cost and high productivity.
- The system can be modified to adapt it to generate a multi-nozzle device.
3D Smart Nozzle answers many costumers’ needs and has the added advantage of being low cost and easy to install. It manages to combine efficiently modern MEMS manufacturing with 3D printers needs.