Micro SLS Fluid Dispersion Manifold
Objective: Design and fabricate an automated recoating device that can repeatably coat previously sintered layers with sub-micron layers of nanoparticle ink.
This project was conducted under the guidance of Dr. Cullinan in the Nanoscale Design & Manufacturing Laboratory. The manifold I aimed to prototype was to be integrated into a Microscale SLS system being designed in the lab by my advisor Aaron Liao.
Background: Selective laser sintering is the process in which a laser is used on thermoplastic powders to melt and solidify the material into layers using computer-aided design (CAD) models. For a microscale system, a nanoparticle ink is used instead of the powder due to risks of the power agglomerating.
The recoating method that inspired me was blade coating. In this technique, a precise amount of solution is deposited behind the blade, which then moves the bead forward to evenly distribute the solution.
I initiated the project by designing fluid dispersion planes with various guiding channel configurations to analyze liquid flow within the channels. Subsequent testing showed that the fluid did not consistently follow the channels and tended to occupy the intervening spaces. As a result, I developed additional iterations incorporating guiding channels with indirect pathways to improve flow control.
These planes were designed using the Retina Engrave laser software (RE3) and fabricated from 1/8″ acrylic sheets. The engraving channels were created with varying depths, adjusted according to the laser power settings.
The second phase of the project entailed designing a mount to integrate the fluid dispersion blade with the larger SLS system. I chose to 3D print the mount using PETG filament due to its rigidity and cost-effectiveness.
The final iteration features two 1/8″ holes for M3 screws to secure the mount to the sintering stage frame. The fluid runs through a 5/32″ OD tube from the syringe pump, which is inserted into a push-to-fit splitting junction. This junction divides the fluid into two streams, ensuring full coverage along the blade’s length. To stabilize the junction, a circular press-fit mount was designed. Additionally, the mount includes holes along its body for zip ties to secure the tubes in place.
