One of the most accurate additive manufacturing technologies on the market is powder bed 3D printers, which use several techniques to melt or sinter powder materials in successive layers to form completed components. These printers use CAD files which are sliced using slicing software and then passed through the 3D printer.

Two well-known technologies of powder bed fusion are Electron Beam Melting (EBM) and Selective Laser Melting (SLM), which use metal alloy powders to print. They each form out of metal powder strong and thick sections, although they have many differences regarding their method and abilities.

Definition of EBM (Electron Beam Melting)

EBM is an additive manufacturing technique that makes use of an electron beam generated by an electron gun directed by magnetic fields. This system was invented by Arcam (which was acquired by GE) together with Chalmers University of Technology in 1993.

Key EBM Process Characteristics

• Uses a super-heated tungsten filament to emit electrons in a vacuum chamber
• Electrons travel at approximately half the speed of light
• Can attain temperatures up to 2,000°C
• Electron beam can be directed at speeds up to 8,000 mm/s
• Requires a vacuum chamber to prevent oxidation
• Uses energized electrons instead of photons (like lasers)

EBM Materials

EBM prints conductive metals and alloys only, including:

• Titanium and titanium alloys (Ti6AL4V)
• Tantalum
• Stainless steel
• Tool steel
• Cobalt chrome (CoCrMo)
• Copper
• Nickel alloys (Inconel® 718)

SLM (Selective Laser Melting) Definition

SLM is a powder bed fusion technology that uses high-powered fiber lasers to selectively melt metal powder. First invented in 1995 and commercialized by SLM Solutions, SLM can utilize up to 12 high-powered lasers simultaneously.

Key SLM Process Characteristics

• Uses high-powered fiber lasers (typically 1000W per laser)
• Fully melts material rather than just sintering
• Operates in an inert gas-filled chamber (not vacuum)
• Layer heights from 20 to 50 microns
• Can adjust beam width for speed or precision optimization

SLM Materials

SLM has a wider range of materials, including:

• Pure metals like titanium
• Tool steel
• Copper
• Stainless steel
• Cobalt chrome
• Aluminum and aluminum alloys
• Precious metals
• Most iron, nickel, cobalt, and copper-based alloys

Detailed Comparison | EBM vs SLM

Technology Differences

Performance Comparison | EBM vs SLM

Speed

EBM Advantages: Prints faster than single-beam SLM due to wider beam and rapid positioning

SLM Response: Multi-beam SLM systems (up to 12 lasers) can match or exceed EBM speed

Accuracy and Surface Finish

SLM Advantages: Better dimensional accuracy, superior surface finish, finer layer resolution

EBM Disadvantages: Rougher surface finish due to larger beam width, requires more post-processing

Build Volume

EBM: Limited to 350mm diameter × 430mm height (cylindrical)

SLM: Up to 600 × 600 × 600mm (larger singular parts possible)

Material Properties and Applications

Part Characteristics

• Both technologies produce:
• High-density parts
• Excellent mechanical properties
• Isotropic material properties
• Strong, lightweight components

EBM Specific:

• Fewer internal stresses
• Heat treatment seldom required
• Up to 98% powder recycling rate

SLM Specific:

• Low porosity
• Higher internal stresses (often requires post-build heat treatment)
• Good dimensional accuracy

Industry Applications

EBM Applications:

• Aerospace (turbine blades)
• Medical (orthopedic implants)
• Automotive components
• Defense applications
• Petrochemical industry

SLM Applications:

• Aerospace
• Automotive
• Medical and dental
• Industrial tooling
• Construction
• Jewelry
• Complete assemblies (not just components)

Advantages and Disadvantages | EBM vs SLM

EBM Advantages:

• Faster printing speed (single beam)
• Higher melt temperatures (up to 2,000°C)
• Fewer support structures required
• Lower internal stresses
• Excellent mechanical properties
• High powder recycling rate
• Can separate beam to multiple locations simultaneously

EBM Disadvantages:

• Limited to conductive materials only
• Requires vacuum chamber (adds complexity, limits size)
• Less product accuracy
• Rough surface finish requiring post-processing
• Expensive machines and materials
• Proprietary technology
• Requires highly skilled technicians
• Limited to smaller parts
• Cooling period required

SLM Advantages:

• Wider range of materials
• Better dimensional accuracy
• Superior surface finish
• Larger build volumes
• Can print entire assemblies
• Operator can adjust beam width for speed vs. precision
• Multiple laser options for increased speed

SLM Disadvantages:

• Slower printing (single beam systems)
• Higher internal stresses
• Requires post-build heat treatment
• More expensive entry-level machines 

Alternative Technologies

Direct Metal Laser Sintering (DMLS)

Direct Metal Laser Sintering Similar to SLM but uses multiple lower-energy lasers and offers superior accuracy with better resolution than both EBM and SLM, though with lower density.

Directed-Energy Deposition (DED)

Can print metals, polymers, and ceramics using filaments or powder. Produces larger products quickly and can handle multiple materials.

Selective Laser Sintering (SLS)

Selective Laser Sintering is Very similar to SLM but prints with plastic rather than metal materials.

Summary

EBM and SLM are both powder bed fusion metal 3D printing technologies that utilize high-intensity heat sources to melt metal powder and produce strong, dense products. The choice between them depends on specific requirements:

Choose EBM when:

• Speed is the priority
• Working with refractory/conductive materials
• Internal stress minimization is important
• Heat treatment should be avoided

Choose SLM when:

• Accuracy and surface finish are critical
• Material variety is needed
• Larger parts or complete assemblies are required
• Higher resolution is necessary

Both technologies continue to evolve, with SLM gaining ground through multi-laser systems that match EBM’s speed advantages while maintaining superior accuracy and material flexibility.

FAQs

How do EBM and SLM differ in the heat source they use?

EBM uses an electron beam, while SLM uses a laser to melt metal powders.

Which process operates in a vacuum chamber?

EBM operates in a vacuum, while SLM works in an inert gas atmosphere.

What metals are commonly processed by EBM and SLM?

EBM is often used for titanium and cobalt-chrome alloys; SLM works with a wider range including stainless steels and aluminum.

How do surface finish and precision compare?

SLM typically produces finer surface finishes and higher resolution parts than EBM.

Which process generally has faster build rates?

EBM can have faster build speeds due to higher energy density and volume melting.

What are typical applications of EBM vs SLM?

EBM is popular in aerospace and medical implants; SLM is used in automotive, aerospace, and tooling.

Which process results in parts with less residual stress?

EBM parts tend to have lower residual stress due to the vacuum environment and preheating.

Is post-processing different between EBM and SLM?

Both require similar post-processing, but SLM parts may need more surface finishing.

Which method is more expensive?

Costs vary, but EBM machines and operation tend to be more expensive than SLM.