Pó para manufatura aditiva

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Additive manufacturing, also known as 3D printing, utilizes various materials in powder form to construct parts and products layer by layer. The type of powder selected depends on the specific additive manufacturing process being used, as well as the desired characteristics of the finished part.

Some of the key types of additive manufacturing powders include:

  • Pós metálicos – Used in powder bed fusion and directed energy deposition processes. Common materials include titanium, aluminum, steel, nickel alloys, and cobalt-chrome.
  • Pós de polímero – Used in powder bed fusion and material jetting processes. Common materials include nylon, ABS, polycarbonate, polystyrene, and thermoplastic polyurethane.
  • Pós cerâmicos – Used in binder jetting and material extrusion processes. Common materials include silica, alumina, zirconia, and porcelain.
  • Sand and Casting Powders – Used in binder jetting processes to create molds and cores for metal castings. Usually silica-based.
  • Biocompatible and Bioactive Powders – Used in medical applications. Common materials include titanium, hydroxyapatite, and tricalcium phosphate.

The characteristics of additive manufacturing powders can significantly influence the properties, quality, accuracy, and performance of printed parts. Key powder properties include:

Additive Manufacturing Powder Composition

Additive manufacturing utilizes metallic, polymeric, ceramic, sand, and other powder materials with specific compositions tailored to various printing processes.

Pós metálicos

TipoCommon Compositions
Ligas de titânioTi-6Al-4V, Ti-6Al-7Nb, Ti-Al-Fe, Ti-Al-Mn, Ti-Al-Sn
Ligas de alumínioAlSi10Mg, AlSi12, Scalmalloy
Steel alloys17-4PH, 316L, 304L, 4140
Ligas de níquelInconel 625, 718; Hastelloy X
Cobalto-cromoCoCrMo

Pós de polímero

TipoCommon Compositions
NylonNylon 11, Nylon 12
ABSAcrylonitrile butadiene styrene
PolicarbonatoBisphenol A polycarbonate
PolystyrenePS, High impact PS
Thermoplastic PolyurethaneTPU

Pós cerâmicos

TipoCommon Compositions
SilicaFused quartz, cristobalite
AluminaAl2O3
ZircôniaZrO2, YSZ (yttria stabilized)
PorcelainMix of glass, clay and feldspar

Sand and Casting Powders

TipoComposições
Silica sandMostly SiO2, with traces of metal oxides and nonmetal oxides
Zircon sandZirconium silicate
Olivine sandMagnesium iron silicate
Chromite sandIron chromium oxide

Bioactive and Biocompatible Powders

TipoCommon Compositions
Titanium and alloysPure titanium, Ti-6Al-4V
HydroxyapatiteCa10(PO4)6(OH)2
Tricalcium phosphateCa3(PO4)2
pó para manufatura aditiva
Additive Manufacturing Powder 3

Pó para manufatura aditiva Propriedades

The key properties of additive manufacturing powders that influence part quality and process performance include:

PropriedadeDescriçãoImportância
Distribuição do tamanho das partículasRange and distribution of powder particle dimensionsAffects powder flowability, packing density, layer uniformity, resolution
Morphology and shapeAspect ratio and shape factors of powder particlesImpacts spreading, packing density, powder flow
DensidadeMass to volume ratio of the bulk powderDetermines weight and dimensional accuracy of parts
FluidezAbility of powder to flow freely under applied stressVital for uniform spreading and recoating of powder layers
Teor de umidadePercentage water content in the powderHigh moisture causes powder agglomerations and printing defects
Composição químicaElemental composition and phases presentDefines mechanical properties, microstructure, and performance of finished parts

Additive Manufacturing Powder Applications

Additive manufacturing powders are used to print functional components across major industries:

SetorFormuláriosMateriais utilizados
AeroespacialTurbine blades, aircraft components, rocket enginesTitanium alloys, nickel alloys, aluminum alloys, cobalt chrome
AutomotivoPrototyping, production of parts like gears, bracketsAluminum alloys, nylon, ABS
MédicoCoifas dentárias, implantes, instrumentos cirúrgicosTitanium alloys, cobalt chrome, stainless steel
ConsumidorJewelry, decorative objects, lighting fixturesPrecious metals like gold, silver; polymers

Additive Manufacturing Powder Specifications

Powder materials used in specific additive manufacturing process conform to certain size, composition, property thresholds:

ProcessoTamanho da partículaGrau da ligaPadrões
Powder bed fusion15-45 mícronsTi-6Al-4V ELI per ASTM F3001ASTM F3049, ASTM F2924, ASTM F2971
Jato de aglutinante20-60 microns420 or 316 stainless steelASTM F3301, MPIF 35
Material jetting5-25 microns60-65 Shore D polyurethane
Directed energy deposition45-150 mícronsInconel 718, 316L stainless steelASTM F3055, ASTM F3302

Additive Manufacturing Powder Suppliers

There is a robust network of suppliers offering a wide array of metal, polymer, ceramic and composite additive manufacturing powders:

EmpresaMateriais em PóFaixa de custo
Tecnologia LPWTitanium alloys, aluminum alloys, stainless steel, nickel alloys$100-$500 per kg
Sandvik OspreyStainless steel alloys, nickel alloys, cobalt alloys$50-$250 per kg
Pós e revestimentos avançadosNylon-based polymers, PEEK, PEKK$80-$600 per kg
The ExOne CompanyStainless steel, tool steel, tungsten carbide, Inconel 625$75-$1000 per kg
HöganäsStainless steel, iron-based alloys$30-$150 per kg
KennametalTungsten carbide-cobalt, 17-4PH stainless$100-$1200 per kg
3DCeramAlumina ceramic, zirconia ceramic, silica$100-$250 por kg

Comparison Between Pós de manufatura aditiva

There are considerable differences between various powder options regarding production processes, cost, part properties and quality:

ParâmetroPolymer PowderMetal PowderCeramic Powder
Taxa de construçãoMédioLentoFast
ResoluçãoMédioAltaMedium to low
Part strengthLow to mediumMuito altoMédio a alto
Part accuracyMédioMédio a altoLow to medium
Acabamento da superfícieMédioAltaLow to medium
Propriedades térmicasLow melting point, low conductivityHigh melting point, high conductivityHigh melting point, low conductivity
Custo por peçaLow to mediumAltaMédio
Pós-processamentoMinimalExtensiveMédio

Advantages of Using Powder Bed Additive Manufacturing

Some of the major advantages of using powder bed technology for manufacturing parts include:

  • Ability to create complex, lightweight geometries not possible with casting or machining
  • Minimal raw material waste since unused powder is recycled
  • Does not require dedicated tooling or molds, allowing rapid prototyping
  • Parts show high strength, durability, heat and corrosion resistance matching wrought materials
  • Porosity and microstructure can be easily controlled
  • Multiple materials and alloys, even graded compositions are printable
  • Just-in-time production with minimal lead times is enabled
pó para manufatura aditiva
Additive Manufacturing Powder 4

Limitations of Powder Bed Additive Manufacturing

Some drawbacks associated with powder bed additive manufacturing that need to be considered:

  • High equipment and operational costs compared to other processes
  • Additional post-processing like Hot Isostatic Pressing is often essential
  • Powder handling procedures and equipment require special attention
  • Printing of certain flexible polymers and rubber-like materials poses challenges
  • Not ideal for very high volume and mass production scenarios
  • Size constraints posed by build chamber dimensions may require redesigning large parts

Perguntas frequentes

Q: What is the most commonly used metal powder for additive manufacturing?

A: Titanium alloys like Ti-6Al-4V are one of the most popular metal powders, due to their high strength to weight ratio and biocompatibility. Aluminum alloys, stainless steels, cobalt chrome, and nickel superalloys are also very commonly used.

Q: How fine are the powders used in AM processes?

A: The typical size range is 10-100 microns, though some processes can use ultrafine 1-10 micron nano powders. Finer powders below 20 microns result in better resolution and accuracy.

Q: What affects the pricing of additive manufacturing powders?

A: Raw material costs, composition, alloy type, particle characteristics like size distribution, flowability and morphology, purity levels, and purchase volume dictate prices. Complex alloys are costlier than simpler ones.

Q: Does the shape of powder particles matter for additive manufacturing?

A: Yes, spherical powders with good flowability, pack density and spreadability perform much better compared to highly irregular or angular powders during printing. The particle shape influences density, layer uniformity and surface finish.

Q: Can any off-the-shelf powders be used for AM processes?

A: Not always – most processes require custom powders with compositions, sizes and shapes tailored specifically for 3D printing applications to ensure ideal flow and fusion. Only established manufacturers with stringent quality control are recommended.

Q: How is unused metal powder reused or recycled in additive manufacturing?

A: After prints, the unsintered powder is filtered to remove large agglomerates and then blended with small quantities of fresh powder, to maintain its flowability, density and composition within tight limits. This powder recycling reduces costs and waste substantially.

Q: What causes layer delamination issues in powder bed 3D printing?

A: Insufficient bonding between layers results from improper preheating, uneven powder distribution, inadequate energy input, unfavorable thermal gradients or poor particle packing density among the common reasons. Optimizing process parameters is vital.

Q: Are additive manufacturing metal powders flammable hazards?

Many reactive elemental and alloy powders are highly flammable when finely divided. Proper ventilation, electrical grounding of equipment, specialized exhaust systems, spark detection and fire suppression are essential safety measures. Powder storage and handling also needs special precautions.

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