3D-Printing Technology: Direct Metal Laser Sintering – DMLS

Direct Metal Laser Sintering, DMLS for short, is a subset of another 3D-printing technology called Selective Laser Sintering. It only uses metal and has a remarkably similar method to Selective Laser Melting (SLM). However, the difference can only be seen on a molecular level where the metal is only sintered together.

How Does Direct Metal Laser Sintering Work?

An inert gas fills the build chamber to remove any oxygen to protect both the powder and the part. The powder and build chamber are also heated to a temperature close to the material’s melting point. It starts with the powder delivery system dispensing a dose of powder and distributing it evenly across the build platform. After which the laser will begin its path, sintering the powder layer by layer. This process repeats until the part has been completely 3D-printed.

What Materials Does Direct Metal Laser Sintering Work?

Just as its name states, this 3D-Printing Technology utilises metals. However, there are different types of metals, which also have different composites.

• Metal Powder
• Plastic/Metal Powder

For a more in-depth look at the materials, click here

Advantages

Materials

As DMLS is an upcoming technology, new materials are constantly being developed. Metals have higher strength and mechanical properties than polymers which is desirable for certain use cases and needs.

Reduced Lead Time

As metal is quite a desirable material, prototypes 3D-printed using this technology has good mechanical properties and is functional.

Recyclable Material

During the DMLS 3D printing process, the powder that are not sintered together are able to be recycled and used in a future build. This reduces the amount of wasted material and allows for the cost of the part to be lower.

Complex Structures

DMLS allows for complex internal structures to be created. Unlike subtractive manufacturing methods, this additive manufacturing process can easily manufacture complex geometries.

Disadvantages

Expensive

The cost of a DMLS 3D printer is high. Besides that, post-processing requires additional equipment which brings up the costs.

Requires Skilled Workers

The DMLS 3D-Printing process requires skilled and knowledgeable workers to optimise the design for the process and to operate the machine with the correct parameters.

Porous Parts

During the 3D printing process, internal holes are created on a microscopic level. This causes the part to have slightly reduced density and affects the material strength. While it can be controlled, it cannot be eliminated, even during post-processing.

Small Parts

At present, only small parts can be built as most DMLS 3D printers have relatively small build volumes.

Messy and Handling

The material must be carefully managed as it is powder-based. Personal Protective Equipment must be worn when operating the machines and handling the powder.

Post-processing

Essential post-processing includes separating the parts from the build plate and support removal. Support removal may be difficult at certain areas because of the design and is time-consuming. Further post-processing must be done if a desired surface finishing is needed.  

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