Podcast
Questions and Answers
What was the first commercialized PBF process developed at the University of Texas at Austin?
What was the first commercialized PBF process developed at the University of Texas at Austin?
- Direct metal laser sintering (DMLS)
- Binder jetting
- Selective laser sintering (SLS) (correct)
- Electron beam melting (EBM)
What are the most common thermal sources for PBF processes?
What are the most common thermal sources for PBF processes?
- Microwaves
- Electric arcs
- Lasers (correct)
- Plasma
What were LS processes originally developed to produce?
What were LS processes originally developed to produce?
- Plastic prototypes using a point-wise laser scanning technique (correct)
- Composite materials using direct metal laser sintering
- Ceramic parts using binder jetting
- Metal components using electron beam melting
Which PBF processes utilize significantly different machine architectures than laser sintering machines?
Which PBF processes utilize significantly different machine architectures than laser sintering machines?
What is one negative effect of loose powder sintering in a build platform?
What is one negative effect of loose powder sintering in a build platform?
What is one positive effect of loose powder sintering in a build platform?
What is one positive effect of loose powder sintering in a build platform?
What causes a region of the powder bed to become much hotter than the surrounding loose powder during part formation in a build platform?
What causes a region of the powder bed to become much hotter than the surrounding loose powder during part formation in a build platform?
Which type of material is suitable for making sacrificial patterns for investment casting using pLS?
Which type of material is suitable for making sacrificial patterns for investment casting using pLS?
What aids in melting out the investment casting pattern after creating the ceramic shell?
What aids in melting out the investment casting pattern after creating the ceramic shell?
Which type of polymers are resistant to degradation at elevated temperatures and chemicals like gasoline and automotive coolants?
Which type of polymers are resistant to degradation at elevated temperatures and chemicals like gasoline and automotive coolants?
Which commercially available polymers for 3D printing are flame-retardant?
Which commercially available polymers for 3D printing are flame-retardant?
Which polymers processed using pLS include biocompatible and biodegradable options?
Which polymers processed using pLS include biocompatible and biodegradable options?
What type of materials have been investigated for bone replacement tissue scaffolds?
What type of materials have been investigated for bone replacement tissue scaffolds?
What type of fillers can enhance the mechanical properties of polymers in PBF?
What type of fillers can enhance the mechanical properties of polymers in PBF?
What metals can be processed using PBF?
What metals can be processed using PBF?
Which materials are widely available for PBF production?
Which materials are widely available for PBF production?
What are some examples of ceramics mentioned in the text?
What are some examples of ceramics mentioned in the text?
Which company developed commercial machines for ceramics?
Which company developed commercial machines for ceramics?
What are some biocompatible materials processed using PBF for medical applications?
What are some biocompatible materials processed using PBF for medical applications?
How many fusion mechanisms are present in PBF processes?
How many fusion mechanisms are present in PBF processes?
What drives solid-state sintering?
What drives solid-state sintering?
What is the primary fusion mechanism used in most AM processes?
What is the primary fusion mechanism used in most AM processes?
Which technology has made some alloys obsolete in favor of engineering-grade alloys?
Which technology has made some alloys obsolete in favor of engineering-grade alloys?
What differs in crystal structures and mechanical properties due to high solidification rates in mLS?
What differs in crystal structures and mechanical properties due to high solidification rates in mLS?
Which type of alloys are not suitable for mLS due to cracking under high solidification rates?
Which type of alloys are not suitable for mLS due to cracking under high solidification rates?
What is the primary purpose of using an enclosed chamber filled with nitrogen gas in Powder Bed Fusion processes?
What is the primary purpose of using an enclosed chamber filled with nitrogen gas in Powder Bed Fusion processes?
What thermal source is commonly used in Powder Bed Fusion processes to maintain an elevated temperature around the part being formed?
What thermal source is commonly used in Powder Bed Fusion processes to maintain an elevated temperature around the part being formed?
What is the purpose of using a counter-rotating powder leveling roller in Powder Bed Fusion processes?
What is the purpose of using a counter-rotating powder leveling roller in Powder Bed Fusion processes?
Which material is commonly used in Powder Bed Fusion processes due to its distinct melting points enabling reliable processing?
Which material is commonly used in Powder Bed Fusion processes due to its distinct melting points enabling reliable processing?
What is required after each layer is completed in a Powder Bed Fusion process?
What is required after each layer is completed in a Powder Bed Fusion process?
What type of materials are well-suited for powder bed processing due to their low melting temperatures, low thermal conductivities, and low tendency for balling?
What type of materials are well-suited for powder bed processing due to their low melting temperatures, low thermal conductivities, and low tendency for balling?
What is used to thermally fuse the material to form the slice cross-section in Powder Bed Fusion processes?
What is used to thermally fuse the material to form the slice cross-section in Powder Bed Fusion processes?
What is required to minimize oxidation and degradation of powdered material during Powder Bed Fusion processes?
What is required to minimize oxidation and degradation of powdered material during Powder Bed Fusion processes?
What type of heating source is used above the feed cartridges to preheat the powder in Powder Bed Fusion processes?
What type of heating source is used above the feed cartridges to preheat the powder in Powder Bed Fusion processes?
What process involves thin layers of powder being fused using a counter-rotating powder leveling roller?
What process involves thin layers of powder being fused using a counter-rotating powder leveling roller?
What is used to lower the build platform by one layer thickness after each layer is completed in Powder Bed Fusion processes?
What is used to lower the build platform by one layer thickness after each layer is completed in Powder Bed Fusion processes?
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Study Notes
Powder Bed Fusion Processes in Additive Manufacturing
- Powder Bed Fusion (PBF) processes have been extended to metal and ceramic powders, with various thermal sources being utilized.
- PBF processes are widely used globally and can be used with a broad range of materials, including polymers, metals, ceramics, and composites.
- The process is increasingly used for the direct manufacturing of end-use products due to comparable material properties to engineering-grade polymers, metals, and ceramics.
- Powder Bed Fusion processes involve thin layers of powder being fused using a counter-rotating powder leveling roller.
- The part building process takes place in an enclosed chamber filled with nitrogen gas to minimize oxidation and degradation of the powdered material.
- Infrared heaters are used to maintain an elevated temperature around the part being formed and above the feed cartridges to preheat the powder.
- A focused CO2 laser beam is directed onto the powder bed to thermally fuse the material to form the slice cross-section.
- After each layer is completed, the build platform is lowered by one layer thickness and a new layer of powder is laid and leveled using the roller.
- A cool-down period is required to allow the parts to come to a low enough temperature that they can be handled and exposed to the ambient atmosphere.
- PBF processes can be used with all materials that can be melted and resolidified.
- Thermoplastic materials are well-suited for powder bed processing due to their low melting temperatures, low thermal conductivities, and low tendency for balling.
- The most common material used in PBF is polyamide, a thermoplastic polymer, commonly known as nylon, which has distinct melting points enabling reliable processing.
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