Note: This is an open-book open-notes exam. Multiple versions are distributed to students. Submissions will be
checked for plagiarism.
First name___________ Last name_______________ UIN___________
1. True or False (20):
(1) The STL file contains information of a set of triangular facets.
(2) Compared to net shape manufacturing processes, an advantage of AM is less material waste.
(3) In AM, the build direction may affect the total printing time and the support structure design.
(4) In a triangulation-based 3D scanning system, it is desired to have a certain angle (i.e., not parallel) between the
camera-object line and the laser-object line.
(5) In two-photon polymerization process, a liquid droplet is used as the feedstock, rather than a vat of liquid resin.
(6) In a mask image projection stereolithography process, gray-scale image can be used to address the printing accuracy
challenge caused by pixelation.
(7) Selective laser melting is a Powder Bed Fusion AM technology that uses full melting as the binding mechanism.
(8) In all 3D printing processes, an object is built by accumulating materials.
(9) In powder bed fusion based processes, the moving melting pool is critical to the printing result.
(10) Compared to vat-photopolymerization based processes, jetting based processes are easier to produce multi-
material objects.
2. Multiple Choice: choose 1~4 answers for each question (30)
(1) Select processes that belong to powder bed fusion AM:
(a) Selective laser melting (b) Laser cusing (c) Direct Energy Deposition (d) Electron Beam Melting
(2) Select AM technologies that can be used for fabricating scaffolds in tissue engineering:
(a) DLP projection stereolithography (b) Fused Deposition Modeling (c) Direct Energy Deposition (d) Inkjet Printing
(3) Choose the feedstock that could be used in Direct Energy Deposition (DED) processes:
(a) Wire (b) powder (c) liquid (d) sheet
(4) Please select factors that may affect the printing resolution in a stereolithography process:
(a) input light energy (b) resin viscosity (c) photosensitivity of the liquid resin (d) size of the light
beam
(5) Please select the challenges that bioprinting is currently facing:
(a) limited choice of printable while biomimetic or bioactive materials
(b) lack of bioprinting definition and bioprinting standards
(c) low cell viability
(d) lack of bio-applications
(6) Please select the technologies that can achieve nanoscale printing resolution:
(a) Electro-hydrodynamic direct writing
(b) Two-photon polymerization
(c) AFM tip based direct writing
(d) Thermal spray direct writing
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