Additive Manufacturing

What best describes additive manufacturing (AM)?

Building a part by joining material from 3D model data, typically layer by layer

Which manufacturing process is subtractive rather than additive?

CNC milling

Which is an example of formative manufacturing?

Injection molding

What is the primary purpose of a prototype during product development?

To evaluate and communicate aspects of a proposed design

In prototyping, what does degree of approximation describe?

How closely a prototype represents the intended product in relevant characteristics

Which is an example of a virtual prototype?

A digital CAD assembly evaluated on a computer

Which is an example of a physical prototype?

A 3D-printed enclosure used for fit testing

Which statement about prototype fidelity is most accurate?

prototype may closely represent some product characteristics while simplifying others

What is a common first step in a digital AM workflow?

Create or obtain a three-dimensional digital model

What does slicing software generally produce?

Layer-by-layer toolpath or build instructions for the printer

What is tessellation in the context of STL data?

Approximating surfaces using interconnected triangles

A key limitation of the STL file format is that it typically does not directly store what information?

Full material and color properties of a part

Why might support structures be necessary in some AM processes?

To stabilize overhangs or anchor features during building

Which activity is typically considered AM postprocessing?

Removing supports and finishing surfaces

Which of the following is one of the seven ISO/ASTM AM process categories?

Material extrusion

Which AM category selectively cures liquid photopolymer in a vat?

Vat photopolymerization

Which category deposits material through a nozzle or orifice?

Material extrusion

Which category uses thermal energy to fuse selected regions of a powder bed?

Powder bed fusion

Which category joins sheet materials to form a part?

Sheet lamination

What distinguishes binder jetting from powder bed fusion?

Binder jetting selectively deposits a liquid bonding agent

Which AM process category feeds material into a focused thermal energy source as it is deposited?

Directed energy deposition

Which process selectively deposits droplets of build material?

Material jetting

Which is a widely recognized design advantage of AM?

Ability to fabricate complex geometries that can be difficult to machine

What is part consolidation?

Combining multiple components into fewer printed components

Why can AM be useful for customized medical devices?

Geometry can be tailored to patient-specific requirements

Which scenario is most likely to favor AM over dedicated high-volume tooling?

Low-volume production of a complex customized component

What is a conformal cooling channel in AM tooling?

A cooling passage shaped to follow the contours of a tool surface

Which is a realistic limitation of AM?

Build speed, material choices, and postprocessing can constrain its use

What is the role of AM standards such as those developed through ASTM and ISO?

Establish consistent terminology, testing methods, and technical practices

What does point-of-need manufacturing emphasize?

Producing needed items near their place or time of use

T/F AM processes generally create parts directly from three-dimensional model data.

True

T/F A prototype must always have the same material and functional performance as the final product.

False

T/F A virtual prototype can be assessed without first producing a physical part.

True

T/F STL files represent curved surfaces with a triangular mesh.

True

T/F All AM technologies use a liquid feedstock.

False

T/F Material extrusion is one of the standardized AM process categories.

True

T/F Binder jetting and powder bed fusion are identical processes.

False

T/F AM automatically eliminates all requirements for finishing and inspection.

False

T/F Part consolidation can reduce the number of individual components in an assembly.

True

T/F AM is always the least expensive approach for mass-producing simple identical parts.

False

Match each additive manufacturing term with its correct definition. Producing prototypes quickly for design evaluation

Rapid Prototyping

Producing parts by joining material from 3D model data

3D Printing

Designing specifically for AM capabilities and constraints

Design for Additive Manufacturing

Commonly used term for AM

Additive Manufacturing

Using digital data to manufacture functional products

Direct Digital Manufacturing

Using AM to produce tooling or tooling components

Rapid Tooling

Material used to support features during fabrication

Support Structure

Position of a component within the build volume

Build Orientation

Operations performed after fabrication to achieve required properties or finish

Post-Processing

Nominal height of each manufactured layer

Layer Thickness

Variation in material properties with direction

Anisotropy

Available manufacturing space within the equipment

Build Volume

Which fabrication process removes material from an initial workpiece?

Subtractive manufacturing

Which operation is primarily a formative process?

Forging

Which process builds a component by successively adding material?

Additive manufacturing

Which is an example of material extrusion AM?

Fused filament fabrication (FFF)

Which AM category includes stereolithography (SLA)?

Vat photopolymerization

Which AM process uses energy to fuse selected regions of a powder bed?

Powder bed fusion

What best describes a hybrid additive-subtractive machine?

It builds material and machines features within an integrated system

What is the first stage of the five-step AM process chain presented in Chapter 2?

3D modeling

During which process-chain stage is a CAD design exported into a printable file format?

Data conversion and transmission

Which activity belongs primarily to checking and preparing?

Repairing mesh errors and choosing build orientation

What is the primary activity during the building stage?

Fabricating the part layer by layer

Which action is an example of post-processing?

Removing supports and cleaning the finished build

A printed bracket warps during fabrication. What is the best next action?

Review orientation, supports, and settings before rebuilding

What does a watertight solid mesh represent?

A closed surface that encloses the intended volume

Why can an open gap in a mesh create problems?

It can prevent the slicer from defining closed cross-sections

A non-manifold edge may occur when:

More than two faces share the same edge

What are inverted normals in a polygon mesh?

Faces whose normal directions point incorrectly

What problem may result from overlapping bodies that are not properly joined?

Unpredictable slicing or build geometry

What is a potential disadvantage of using an unnecessarily dense triangle mesh?

Larger files and increased processing requirements

What is the most appropriate response to an STL file with holes and inverted normals?

Repair and verify the mesh before slicing

What is the primary function of a support structure?

Stabilize features that may deform or fail during fabrication

Under the Y-H-T guideline, which feature often builds more easily without supports?

A sloped Y-shaped feature within process limits

For an H-shaped feature, what is an important support consideration?

The unsupported bridge span length

Why might a T-shaped overhang need supports?

Its horizontal arm may sag or fail without underlying material

Which statement about support material is accurate?

Some powder-based processes allow recovery of unfused surrounding powder

What trade-off should guide support placement?

Build reliability, material consumption, surface marks, and removal access

Which statement best describes STL?

A widely supported format representing surfaces with triangles

What is an advantage of 3MF over basic STL when supported by the software?

It can carry geometry plus additional manufacturing information

Which information should be checked before transferring a model to a printer?

Units, scale, revision, and software compatibility

What does slicing software generate from a prepared model?

Layer cross-sections and process instructions for the selected machine

What is infill in a material-extrusion print?

The internal structure defined within the part

Why review the sliced preview before starting a build?

To check layers, supports, placement, and estimated resource use

Which change could improve build-plate productivity?

Arrange multiple compatible parts while maintaining adequate spacing

Which factor can increase risk of damage during post-processing?

Aggressive support removal from delicate features

What is the purpose of inspection and acceptance?

Determine whether the part meets requirements and should be accepted, reworked, or rebuilt

T/F Milling and turning are examples of subtractive manufacturing.

True

T/F The AM process chain must always proceed without returning to an earlier stage.

False

T/F A watertight mesh fully encloses the intended build volume.

True

T/F Increasing the number of mesh triangles always guarantees a better printed part.

False

T/F A short bridge may print without supports depending on the process and settings.

True

T/F All AM processes require identical support geometry and removal procedures.

False

T/F An STL file can contain geometry defects even when the CAD model looks correct on screen.

True

T/F Slicing preview should be skipped if a file opens without an error message.

False

T/F Some AM builds can be monitored with cameras or automated notifications.

True

T/F A completed build automatically satisfies all dimensional and functional requirements.

False

Match each additive manufacturing process-chain activity or concept to its correct description. Cleaning, curing, support removal, and finishing as required

Post-processing

Automated layer-by-layer fabrication of the part

Building

Mesh repair, orientation, support generation, and slicing setup

Checking and preparing