3D: Powder-Based AM System

Powder Based Systems

1. Selective Laser Sintering (SLS)

2. Selective Laser Melting (SLM)

3. Arcam’s Electron Beam Melting (EBM)

4. BeAM’s LMD Systems

5. DMG MORI’s Hybrid AM

6. ColorJet Printing Technology (CJP)

7. HP Multi Jet Fusion (MJF)

Selective Laser Sintering (SLS)

• thin layer of powder is deposited onto the chamber

• a cross section is selectively “drawn” by a CO2 laser

• laser sinters powder to create soldi mass

• process is repeated

Materials used for SLS

• DuraForm

• CastForm

Sinter Bonding

• raised to above the glass-transition temperature

• straight from powder into solid. (no liquid phase!)

• must take place in a gas-free environment to prevent oxidation or explosion

• cooling is also necessary

SLS Advantages & Disadvantages

Advantages

• good stability

• wide range of materials

• no need for supports

• little postprocessing

Disadvantages

• unit is large

• requires a lot of power

• poor surface finish

Selective Laser Melting

• a laser beam selectively goes across the surface of a layer of powdered metal

• the metal is melted (parts are close to 100% dense)

• no gas in chamber is allowed

SLM Advantages & Disadvantages

Advantages:

• high quality

• large range of metal materials

• complex geometries

• accurate

Disadvantages:

• unit is large

• requires a lot of power

• slow process

• specific range of powder size required

Types of SLM scanning strategies

• this allows us to reduce the stress of the product

1. Meander hatch pattern

2. Stripe hatch pattern

3. Chessboard hatch pattern

Arcam’s Electron Beam Melting (EBM)

• metal!

• for aerospace market and racing industry (cause of large components)

• a thin layer of powder is spread onto the surface

• the laser aims at the powder to melt it

• the surface is lowered and the process is repeated

EBM advantages & disadvantages

advantages

• strong products

• high accuracy

• neat finishing

• fast

disadvantages

• need to maintain vacuum chamber

• requires a lot of power

• electron beam can produce gamma rays

application

• medical implants

• aerospace

BeAM’s LMD Systems

• aka: directed energy deposition

• highest level of development for industrial applications

• a fibre laser focuses on a metal substrate and ejects powder while heating it up and the process is repeated to create multiple layers

• (laser/nozzle is mounted on the z-axis) allows for 5 axis of freedom

LMD Advantage & Disadvantage

Advantages:

• strong product

• can create complex parts

• can add material onto existing parts

• can blend materials

• low cost powder

Weakness

• cant print super complex parts

• surface finish isn’t that nice

• not as accurate

DMG MORI’s Hybrid AM

• Hybrid = additive + subtractive

• powder is released from nozzle while simultaneously being heated up

• a shielding gas around the nozzle products against oxidatinon

• once finished, milling process begins

DMG MORI’s Hybrid AMG Advantages & Disadvantages

Advantages:

• 10x faster than powder bed fusion

• doesn’t require support structures

• can use multi-materials

Disadvantages:

• limited choice of materials

• challenging to process and set up

• requires heat, therefore materials can change

ColorJet Printing (CJP)

• depends on…

  • packing density

• powder is spread out over a surface

• adhesive bonding agent drops onto powdered layer and binds the particles together

• binding agent seeps through gaps between powder and causes the capillary forces to merge the particles together

• process is repeated

CJP advantages & disadvantages

advantages

• high speed

• versatile

• simple to operate

• less waste

• complex colors

disadvantages

• weak

• poor surface finish

applications:

• concept modelts

HP’s Mutli Jet Fusion

• a layer of material is deposited onto the plate

• then the machine prints fusing agents in a detailed way onto the layer of material and is immediately cured with infrared energy

• the plate moves down and the process is repeated

Multi Jet Fusion Advantages & Disadvantages

Advantage

• fase

• low cost

• high quality/functional parts

• accuracy and details

• can add last minute additional parts

Disadvantage

• stl format is not recommend for this printer (AMF or 3MF preferred instead)

• requires post-processing

• limited materials