3D PRINTING

Selective laser sintering • Stereolithography

What is Selective Laser Sintering?

Selective laser sintering (SLS) is an additive manufacturing technique that uses a laser as the power source to sinter powdered material (typically metal or polymer), aiming the laser automatically at points in space defined by a 3D model, binding the material together to create a solid structure. It is similar to direct metal laser sintering (DMLS); SLS (as well as the other mentioned AM techniques) is a relatively new technology that has mainly been used for rapid prototyping and for low-volume production of component parts so far. Production roles are expanding as the commercialization of AM technology improves.

What is Stereolithography?

Stereolithography (SLA or SL; also known as optical fabrication, photo-solidification, solid free-form fabrication and solid imaging) is an additive manufacturing or 3D printing technology used for producing models, prototypes, patterns, and production parts up one layer at a time by curing a photo-reactive resin with a UV laser or another similar power source.

Optimal
batch sizes

1 to 100
pieces

Maximum
component size

580 x 580 x 400
mm

Layer
thickness

0.1
mm

Production
speed

3 to 5
days

Possible materials

How Does SLS Work?

1.

3D Model is made.
2.

The SLS machine begins sintering each layer of part geometry into a heated bed of nylon-based powder.
3.

After each layer is fused, a roller moves across the bed to distribute the next layer of powder. The process is repeated layer by layer until the build is complete.
4.

When the build finishes, the entire powder bed with the encapsulated parts is moved into a breakout station, where it is raised up, and parts are broken out of the bed.
5.

An initial brushing is manually administered to remove a majority of loose powder. Parts are then bead blasted to remove any of the remaining residual powder before ultimately reaching the finishing department

1

After the 3D Model is made the SLS machine begins sintering each layer of part geometry into a heated bed of nylon-based powder.

2

After each layer is fused, a roller moves across the bed to distribute the next layer of powder. The process is repeated layer by layer until the build is complete.

3

When the build finishes, the entire powder bed with the encapsulated parts is moved into a breakout station, where it is raised up, and parts are broken out of the bed.

4

An initial brushing is manually administered to remove a majority of loose powder. Parts are then bead blasted to remove any of the remaining residual powder before ultimately reaching the finishing department.

How Does SLA Work?

1.

The SLA machine starts to draw the support structures layer by layer. The part itself is followed with an ultraviolet laser aimed onto the surface of a liquid thermoset resin.
2.

When a layer is imaged on the resin surface, the build platform shifts down and a recoating bar moves across the platform to apply the next layer of resin. The process is carried out layer by layer until the build is done.
3.

Newly built parts are taken out of machine and additional resins are removed with solvents. When the parts are completely clean, the support structures will be removed manually. From there, parts will undergo a UV-curing cycle to fully dry and solidify the outer surface of the part.
4.

The application of custom or customer-specified finishing will be implemented. Minimal UV and humidity exposure shall be applied on the parts so that they don’t degrade.

1

The SLA machine starts to draw the support structures layer by layer. The part itself is followed with an ultraviolet laser aimed onto the surface of a liquid thermoset resin.

2

When a layer is imaged on the resin surface, the build platform shifts down and a recoating bar moves across the platform to apply the next layer of resin. The process is carried out layer by layer until the build is done.

3

Newly built parts are taken out of machine and additional resins are removed with solvents. When the parts are completely clean, the support structures will be removed manually. From there, parts will undergo a UV-curing cycle to fully dry and solidify the outer surface of the part.

4

The application of custom or customer-specified finishing will be implemented. Minimal UV and humidity exposure shall be applied on the parts so that they don’t degrade.

Each process has its own advantages and disadvantages
and is therefore used for different purposes.

Selective laser sintering (SLS)

During laser sintering, parts are made from polyamide with good mechanical properties, similar to injection molded parts are produced. This method is particularly attractive and often the most cost-effective solution for small batch sizes. However, it falls short in terms of surface quality and level of detail.

Stereolithography (SLA)

The component structure is drawn into a liquid photopolymer using a UV laser which hardens the surface, and the component is built up layer by layer. For overhanging parts, stereolithography requires support structures constructed from the same material. This method is suitable for large parts which require good surface quality.

Industries Applied by 3D Printing

Medical Devices
Scientific Instruments
Car Parts
Home Appliances

Mechanical Engineering
Robotics
Automation Devices
Industrial Design