Ch.1 Introduction

Question 1

Describe “form”, “fit”, and “function”

Answer 1

Form: general shape and purpose
Fit: size/ built to tolerance standards
Function: parts work as designed

Question 2

What function can be carried out on point cloud data using reverse engineering? How do these tools differ from conventional 3D CAD?

Answer 2

Point cloud allows for replication of exact geometry and size of object through 3D scan (modeled by discretized points)

CAD is for design modify or analysis of part not duplicating

Question 3

Under what circumstances does AM have the advantage over CNC machining?

Answer 3

• a wider range of materials supported
• combine multiple parts into one product
• supports complex geometries/internal features
• build process simplified without requiring advanced skills or additional tools

Question 4

When does CNC machining have the advantage of AM?

Answer 4

• can produce parts with well-defined properties
• homogenous/predictable quality
• better part tolerance
• isotropic build to maintain desired mechanical strength

Question 5

What is the difference between end-use parts and prototypes?

Answer 5

End-use parts: The product is fully functional, ready to be sold or integrated into an assembly.

Prototypes: products still in the developmental stage, used to test or validate some physical or functional aspect

Question 6

What are the categories of AM technologies?

Answer 6

Material Extrusion
Material Jetting
Binder Jetting
Powder Bed Fusion
VAT photopolymerization
Sheet Lamination
Directed Energy Deposition

Question 7

What are types of Metal AM technologies?

Answer 7

Bound Metal Deposition
MELD

Direct Metal Laser Sintering (laser traces geometry, high pressure/heat compact powder for solidification)

Electron Beam Melting (fusion of metal powder by electron beam)

Atomic Diffusion AM

Question 8

Why is NC machining often referred to as a 2.5D process?

Answer 8

2.5D because the orientation and movement of the system are restricted to 2 axes while 1 is held constant

Question 9

What are 4 ways AM relies on computers that are different from traditional manufacturing?

Answer 9

Slicing system: slicing algorithm to generate 2D cross-section

Support generation

Process Setup: build parameters need to be set up

Process monitor: monitors build process

Question 10

What is AMF format? How is different from STL?

Answer 10

AMF is a standardized file format that stores geometry data using triangular vertices

Advantages over STL:
- able to store additional info about part besides only geometry

• smaller file size
• lower error rate –> minimizes need of file repair
• accommodate free-form curves and surfaces
• easier to receive updates

Question 10

What is the resolution of AM vs. CNC?

Answer 10

AM: tens of microns
CNC: 1000-several thousandths of an inch

Question 10

How is material jetting different from material extrusion?

Answer 10

Jetting deposits selectively or as continuous droplets (inkjet)

Extrusion deposits a continuous stream under constant pressure (FDM)