Session: 16-01-01: Government Agency Student Poster Competition

Paper Number: 149925

149925 - Reconfiguration of a Digital Light Projection 3d Printer and Scale Optimization for Printing Minute 3d Objects 

The main objective of this project is to reconfigure a 3D printer to print on the micrometer scale.  Additive Manufacturing (AM) is the process of forming objects by stacking 2-dimensional (2D) layers one on top of each other to form a 3-dimensional structure. This technology has transformed the manufacturing industries, producing objects with a close-to-perfect external finish in record times. Various categories of AM exist and have been listed into 7 main branches by the American Society for Testing Materials including Material Extrusion, material jetting, photopolymerization, binder jetting etc.  

DLP is a type of AM technology that uses UV light to cure resins and produce 3D objects. A model Projection DLP printer is made up of a few essential parts that corroborate the printing process. The primary and typical elements you can anticipate in a DLP 3D printer system include the DLP printer frame (houses the various parts of the system and firmly holds them in position), the optical system or photomask (projects the image from the CAD software), the Digital Micromirror Device (DMD, an array of millions of micromirrors– receives the image from the photomask and reflects it onto the resin), the VAT chamber (contains the resin and receives the image reflected from the DMD), and the build head (the surface on which the object is printed on).

In our approach, we examined the lens equations to show that if the distance to the DMD, object distance (), is increased to exactly twice the focal length of the lens, the image formed at image distance () will be exactly the size of the DMD. That is, the magnification will be unity (1×), or actual size. If the DMD is moved to a greater distance,  >> f, the image formed at  will be smaller than the DMD. This means that demagnification is possible.

In our reconfiguration design, we designed a novel optical system (with silica glass of refractive index – 1.45) using COMSOL Multiphysics, having a varied radius of curvature and image and object distances. A bitmap image of a square area of 0.04 was demagnified to a 0.0025 square area. One thousand rays (1000) propagated from the object board through the optical system to the image board without ray interference. A defined release angle to slightly fill the pupil of the optical system.

In optimizing our process parameters, we printed minute samples of a maximum dimension of 35µm with different exposure times using a DLP 3D printer, gold-sputtered and viewed the printed image under a scanning electronic microscope.

Presenting Author: Enoch Ameyaw Southern University A&M College

Presenting Author Biography: I am a second year masters student in SUBR, studying mechanical engineering. I love to play football and basketball during my leisure time.

Authors:

Enoch Ameyaw Southern University A&M College
Fareed Dawan Southern University A&M College
Patrick Mensah Southern University A&M College