Additive Manufacturing Overview

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Questions and Answers

What is the primary purpose of converting a CAD model to STL format?

To create a detailed engineering drawing

To export as a 3D printing file

To simplify the model's geometry for AM (correct)

To enhance the visual quality of the model

The conversion to STL format is a manual process requiring significant user intervention.

False

Name one application area of additive manufacturing that does not involve conventional CAD modeling.

Medical modeling

The eight steps in the additive manufacturing process include conceptualization and CAD, conversion to STL, transfer and manipulation of STL file, _____, build, part removal and cleanup, post-processing of part, and application.

machine setup Signup and view all the answers

Match the type of additive manufacturing system with its description:

Molten material systems = Extrude melted materials layer by layer Solid sheets = Adhere layers of sheet materials together Powder-based systems = Utilize powdered materials that are fused together Photopolymer based systems = Use light to cure liquid resin Signup and view all the answers

What are common considerations in the design for additive manufacturing?

Part orientation and removal of supports Signup and view all the answers

Energy density is an important factor in metal additive manufacturing systems.

True Signup and view all the answers

What is one of the initial actions required prior to building a part?

Use the visualization tool Signup and view all the answers

What is the significance of part removal and cleanup in the additive manufacturing process?

Ensures the final product is ready for use and free of excess material. Signup and view all the answers

All AM machines must run a variety of materials with numerous setup parameters.

False Signup and view all the answers

What is the purpose of repositioning the part before building?

To allow it to be built at a specific location within the machine. Signup and view all the answers

Parts may require _____ or coating allowances.

shrinkage Signup and view all the answers

Match the following actions with their related descriptions:

Segmentation of STL files = Divide parts for easier handling Manual finishing = Prepare parts for final use Verify the part = Ensure accuracy before building Machine setup = Configure parameters for operation Signup and view all the answers

During which phase does the process switch to computer-controlled building?

Layer-based manufacturing phase Signup and view all the answers

All AM machines alert the user when the build is complete or when there is no source material remaining.

True Signup and view all the answers

What does significant manual finishing typically entail for parts produced by AM machines?

It involves cleaning and preparing parts for ready-to-use condition. Signup and view all the answers

What is the role of support structures in additive manufacturing?

To stabilize the part during the building process Signup and view all the answers

Post-processing tasks always require the use of power tools.

False Signup and view all the answers

What are some common post-processing techniques used in additive manufacturing?

Abrasive finishing, polishing, sandpapering, and application of coatings. Signup and view all the answers

AM materials often have small _____ trapped inside them, leading to potential failure under stress.

voids Signup and view all the answers

What is a potential consequence of poor technique in support removal?

Low quality output of the part Signup and view all the answers

Match the additive manufacturing issues with their descriptions:

Anisotropic properties = Different properties in different directions Material degradation = Material not bonding or crystallizing optimally Support removal = Often requires manual skill to avoid damaging parts Application specificity = Varies by the requirements of the final product Signup and view all the answers

Many applications using AM processes do not require high performance from their _____ .

components Signup and view all the answers

Why may parts produced by additive manufacturing behave differently than those made by conventional methods?

They may have voids, anisotropic properties, or material degradation. Signup and view all the answers

What is the nominal layer thickness range for most SL technology machines?

0.05 - 0.1 mm Signup and view all the answers

Thicker layers in additive manufacturing (AM) lead to parts being built more precisely.

False Signup and view all the answers

What material property must be considered during post-processing that involves heat?

Heat resistance or melting temperature Signup and view all the answers

In powder-based systems, there is no need to use _____ .

supports Signup and view all the answers

Match the following AM technologies with their characteristics:

Binder Printing = Parts can be colored using colored binder material Droplet Deposition = Possible to modify the support material as it prints Photopolymer-Based Systems = Requires support from the same material used for the part Powder-Based Systems = Deposits a bed of powder layer-by-layer Signup and view all the answers

What is an advantage of photopolymer-based systems?

Good accuracy with thin layers Signup and view all the answers

Newer resins in photopolymer systems offer improved temperature resistance and strength.

True Signup and view all the answers

What type of machine typically has a nominal layer thickness of 0.254 mm?

FDM Dimension machines Signup and view all the answers

What is a key requirement for molten material systems that melt and deposit materials in a molten state?

Support structures Signup and view all the answers

Extrusion processes like FDM always generate supports automatically.

False Signup and view all the answers

What is one of the challenges faced when cleaning parts produced by lamination methods?

The laborious process of waste material removal. Signup and view all the answers

Exposure to _____ and excessive light should be avoided in material handling.

moisture Signup and view all the answers

Match the following application areas with their respective technology:

FDM = Additive Manufacturing Computerized Tomography (CT) = Medical modeling 3D ultrasound = Medical modeling Magnetic Resonance Imaging (MRI) = Medical modeling Signup and view all the answers

Which of the following is NOT a factor to consider in metal systems?

Color of the material Signup and view all the answers

List two design considerations for additive manufacturing.

Part orientation, Removal of supports Signup and view all the answers

Some machines in additive manufacturing must be kept away from _____ environments.

dirty or noisy Signup and view all the answers

Which of the following is a type of Vat Photopolymerization process?

Stereolithography Signup and view all the answers

Two-Photon Vat Photopolymerization offers only advantages and no drawbacks.

False Signup and view all the answers

What is one of the key components of photopolymer chemistry?

Photo initiator system Signup and view all the answers

The process that models irradiance and exposure in Vat Photopolymerization is known as _____ .

Photopolymerization Process Modeling Signup and view all the answers

Match the following scan patterns with their descriptions:

WEAVE = A pattern that helps in smooth layering Layer-based build phenomena = Patterns related to the construction of layers in photopolymerization ACES = An advanced vector scan pattern for enhanced accuracy STAR-WEAVE = A complex pattern designed for intricate builds Signup and view all the answers

Which of the following radiation types is primarily used to cure commercial photopolymers?

UV light Signup and view all the answers

Epoxy and vinylether are examples of free radical polymerization.

False Signup and view all the answers

What is the role of a photoinitiator in photopolymerization?

To convert physical energy of light into chemical energy in the form of reactive intermediates. Signup and view all the answers

Photopolymer resins must be cleaned, post-cured, and _____ after building.

finished Signup and view all the answers

Match the following photopolymerization processes with their respective characteristics:

Cationic polymerization = Epoxy and vinylether Interpenetrating polymer networks = Uses multifunctional monomers Resin formulation = Acrylate-based Free radical polymerization = Acrylates and epoxides form networks Signup and view all the answers

What component of the laser scan VP machines is responsible for liquid resin application?

Recoating system Signup and view all the answers

Both di-functional and higher functionality monomers are commonly used in SL resins.

True Signup and view all the answers

Name two main subsystems of vector scan VP machines.

Laser and optics systems, control system. Signup and view all the answers

Which approach in photopolymerization does not require recoating of the resin layer?

Two-photon approach Signup and view all the answers

In the microelectronic industry, visible light is predominantly used for photomask materials.

False Signup and view all the answers

What device is used to pattern the large radiation beam in the mask projection approach?

Digital Micromirror Device Signup and view all the answers

In photopolymerization processes, the _____ scan approach is typical of commercial SL machines.

vector Signup and view all the answers

Match the photopolymerization approaches with their descriptions:

Two-photon = High resolution point-by-point Layer-wise = Successive layer applications Mask projection = Entire layers irradiated at once Vector scan = Scanning laser beams needed Signup and view all the answers

What type of light is primarily used in photopolymerization processes?

Ultraviolet (UV) Signup and view all the answers

Charles Hull discovered solid polymer patterns by exposing UV curable materials to a scanning laser.

True Signup and view all the answers

What is one common application of photo-curable resins in dentistry?

Sealing the top surfaces of teeth to prevent cavities Signup and view all the answers

The mid 1980s marked the beginning of SL technology due to Charles Hull's experiments with _____ curable materials.

UV Signup and view all the answers

Match the following radiation types with their uses in curing commercial photopolymers:

Ultraviolet rays = Primarily used in photopolymerization processes X-rays = Used in treating medical materials Visible light = Alternative curing method Gamma rays = Used in various curing applications Signup and view all the answers

What is a significant drawback of vat photopolymerization technology?

Limited chemistries for photopolymers Signup and view all the answers

The surface finish of SL parts can range from submicron to over 100 um Ra depending on the orientation of the surfaces.

True Signup and view all the answers

What is the maximum size of fabrication structure achievable with the specified microsterolithography process?

10 mm x 10 mm x 10 mm Signup and view all the answers

The minimum size of a hardened polymer unit in the microsterolithography process is _____ in the x and y directions.

5 µm x 5 µm Signup and view all the answers

Match the advantages of vat photopolymerization technology with their descriptions:

Surface finish = Varies based on surface orientation Accuracy = 0.002 in/in Speed = Fast production compared to laser scanning Flexibility = Supports different configurations Signup and view all the answers

Which of the following statements about mask projection VP technologies is true?

They are faster compared to laser scan SL technologies. Signup and view all the answers

Photopolymers used in additive manufacturing are known for their exceptional impact strength and durability.

False Signup and view all the answers

What is the position accuracy achieved in the x-y directions during the microsterolithography process?

0.25 µm Signup and view all the answers

When laser light is focused on a particular area for a long time, then that particular area alone will be heated.

True Signup and view all the answers

Laser technology is well suited for integration into modern systems like CAD and CAM?

True Signup and view all the answers

Electromagnetic waves that are applied in mobile phones are called:

Radio waves Signup and view all the answers

Purposes of laser material processing are based on the interaction of lasers with solid materials.

True Signup and view all the answers

The relation between the wavelength λ and frequency is:

Inversely proportional Signup and view all the answers

All the radiation in electromagnetic waves have the same wavelength.

False Signup and view all the answers

What is the full form of LASER and the acronym stands for?

Light Amplification by Stimulated Emission of Radiations Signup and view all the answers

The smallest particle (quantum) in light is called _____ .

Photons Signup and view all the answers

Study Notes

Additive Manufacturing

Converting a CAD model to STL format simplifies the model's geometry for Additive Manufacturing (AM).
The conversion to STL format is not a manual process and does not require user intervention.
Medical modeling is an application area of AM that does not involve conventional CAD modeling.
The eight steps in the AM process include conceptualization and CAD, conversion to STL, transfer and manipulation of STL file, machine setup, build, part removal and cleanup, post-processing of part, and application.
Common considerations in design for AM include part orientation and removal of supports.
Energy density is an important factor in metal AM systems.
Visualization tools are used to check the part before building.
Part removal and cleanup ensures the final product is ready for use and free of excess material.
AM machines do not all run a variety of materials with numerous setup parameters.
Repositioning the part before building allows it to be built at a specific location within the machine.
Parts may require shrinkage or coating allowances.
Segmentation of STL files divides parts for easier handling.
Machine setup configures parameters for operation.
Manual finishing prepares parts for final use.
The process switches to computer-controlled building during the layer-based manufacturing phase.
All AM machines alert the user when the build is complete or when there is no source material remaining.
Significant manual finishing typically entails cleaning and preparing parts for ready-to-use condition.
Support structures stabilize the part during the building process.
Post-processing tasks do not always require the use of power tools.
Common post-processing techniques include abrasive finishing, polishing, sandpapering, and application of coatings.
AM materials often have small voids trapped inside them, leading to potential failure under stress.
Poor technique in support removal can lead to low-quality output of the part.
Anisotropic properties refer to different properties in different directions.
Material degradation refers to material not bonding or crystallizing optimally.
Support removal often requires manual skill to avoid damaging parts.
Application specificity varies by the requirements of the final product.
Parts produced by AM may behave differently than those made by conventional methods due to voids, anisotropic properties, or material degradation.
The nominal layer thickness range for most SL technology machines is 0.05 - 0.1 mm.
Thicker layers in AM do not lead to parts being built more precisely.
Heat resistance or melting temperature must be considered during post-processing that involves heat.
Powder-based systems do not require supports.

Photopolymer-Based Systems

Photopolymer-based systems rely on light to cure liquid resin.
Photopolymer-based systems require support from the same material used for the part.
Photopolymer-based systems offer good accuracy with thin layers.
Newer resins in photopolymer systems offer improved temperature resistance and strength.
FDM Dimension machines typically have a nominal layer thickness of 0.254 mm.

Molten Material Systems

Molten material systems extrude melted materials layer by layer.
Extrusion processes like FDM do not always generate supports automatically.
Cleaning parts produced by lamination methods is a laborious process due to waste material removal.
Materials should be kept away from moisture and excessive light during handling.

Laser Systems

The smallest particle in light is called a photon.
The full form of LASER is Light Amplification by Stimulated Emission of Radiations.
Laser material processing is based on the interaction of lasers with solid materials.
The relationship between wavelength and frequency is inversely proportional.
Electromagnetic waves have different wavelengths.
Charles Hull discovered solid polymer patterns by exposing UV curable materials to a scanning laser.

Vat Photopolymerization

Vat photopolymerization processes can be found in Stereolithography (SL).
Two-Photon Vat Photopolymerization has both advantages and drawbacks.
Photo Initiator System is a key component of Photopolymer chemistries.
Photopolymerization Process Modeling is used to model irradiance and exposure in Vat Photopolymerization.
Di-functional and higher functionality monomers are commonly used in SL resins.
Vector Scan VP machines have two main subsystems: laser and optics systems, control system.
The Two-photon approach does not require recoating of the resin layer.
Visible light is not predominantly used for photomask materials in the microelectronic industry.
A Digital Micromirror Device is used to pattern the large radiation beam in the mask projection approach.
The vector scan approach is typical of commercial SL machines.
Ultraviolet (UV) light is primarily used in photopolymerization processes.
Epoxy and vinylether are not examples of free radical polymerization.
A photoinitiator converts physical energy of light into chemical energy in the form of reactive intermediates.
Photopolymer resins must be cleaned, post-cured, and finished after building.
The recoating system is responsible for liquid resin application in laser scan VP machines.
The Layer-wise approach in photopolymerization requires recoating of the resin layer.

Microstereolithography

The maximum size of a fabrication structure achievable with the microsterolithography process is 10mm x 10mm x 10mm.
The minimum size of a hardened polymer unit in the microsterolithography process is 5 µm x 5 µm in the x and y directions.
The position accuracy achieved in the x-y directions during the microsterolithography process is 0.25 µm.

Design Considerations for Additive Manufacturing

It is important to consider part orientation and removal of supports in design for AM.
AM machines should be kept away from dirty or noisy environments.

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Description

Explore the essential steps and considerations in Additive Manufacturing (AM), including the conversion process to STL format and applications in medical modeling. Understand the importance of energy density and the role of visualization tools in the AM workflow for achieving high-quality parts.