Direct Metal Laser Sintering (DMLS) for Metal 3D Printing

Maximum Part Size

Layer Thickness

Minimum Feature Size

Typically, for well-designed parts, with a designated build direction, tolerances of +/- 0.1 mm to +/- 0.2 mm + 0.005 mm/mm are expected and achieved

Aluminium
Maraging Steel
Inconel
Cobalt Chrome
316L Stainless Steel
Titanium

We use multiple 3D printing equipment for the production of metal components, which offer large build sizes, produce accurate parts, and provide quick turnaround times. Our EOS and Concept Laser 3D printing equipment can handle both reactive and non-reactive metal powder.

DMLS is a 3D printing process, which uses a computer-controlled, high-power laser beam to melt and fuse layers of metallic powder together.

Direct metal laser sintering (DMLS) is an industrial 3D printing process that builds fully functional - rapid metal prototypes and production parts in 7 days or less. A range of metals produce final parts that can be used for end-use applications.

DMLS design guidelines will help you understand capabilities and limitations.

The components of a DMLS 3D printer include: laser unit (1), laser beam (2), mirror/galvo motor system, beam steering (3), focused & directed beam (4), build chamber (5), manufactured part (6), recoater blade (7), powder supply container (8), pistons (9), and powder collection container (10).

The DMLS machine begins begins the 3d metal printing process by sintering each layer—first the support structures to the base plate, then the part itself—with a laser aimed onto a bed of metallic powder. After a cross-section layer of powder is micro-welded, the build platform shifts down and a recoater blade moves across the platform to deposit the next layer of powder into an inert build chamber. The process is repeated layer by layer until the build is complete.

When the build finishes, an initial brushing is manually administered to parts to remove a majority of loose powder, followed by the appropriate heat-treat cycle while still fixtured in the support systems to relieve any stresses. Parts are removed from the platform and support structures are removed from the parts, then finished with any needed bead blasting and deburring. Final DMLS parts are near 100 percent dense.

DMLS material data sheets can be found in our Material Comparison Guide

• Capable of working with nearly any alloy
• Mechanical properties equal to conventionally formed parts
• Can make geometries that are impossible to machine or cast
• Ability to produce unique parts
• Does not require special tooling like castings

Direct Metal Laser Sintering is useful for a multitude of applications, it is widely used in the aerospace industry for things such as air ducts, fixtures or mountings.

3D Metal printing is also useful in the medical industry, where devices are complex and products are high value. Customer requirements are generally very specific/exact.

DMLS 3D Printing is also used in a variety of other areas such as for rotors, impellers, complex bracketing and is also a major player in the automotive industry.

• Ensuring parts are supported properly during the build process, or avoiding exceptionally difficult build shapes will help avoid warping and curl
• Minimum allowable unsupported bridge distance is 2mm
• Walls below 1mm must have a wall height-to-thickness ratio of less than 40:1 or the structure may fall apart.
• Thick walls are wasteful and inefficient, best to hollow these with a honeycomb or lattice structure - this will reduce cost whilst preserving structural integrity 
• Tree-like structures, gentle twisting seashell curves, and other organic shapes are all cost-effective
• Consider DMLS for highly complex structures, which are difficult to machine
• Standard DMLS parts will have a finish similar to that of a sand casting. If requiring smoother finishes there are a number of finishing operations available including bead blasting, painting and 3D post-machining
• Metal sintered parts are 99% as dense as conventionally formed metal materials
• Multi-part assemblies can be greatly simplified using DMLS
• Stair-stepping will occur on angled surfaces, a pyramid shaped part would have rougher surfaces than a cube
• Extra material should be considered when close tolerance holes or features are required - for reaming or secondary machining 
• The entire build area of 250mm³ can be utilised 
• Direct Metal Laser Sintering is a great option for designers aiming for lightweight parts, this reduces the total cost of your part.
• Inconel 718 is suited to extreme environments such as high temperature applications where aluminium and steel would succumb to creep.
• Maraging Steel 1.2790 a pre-alloyed, ultra high strength, steel.
• Titanium Ti6Al4v is a well-known light alloy, popular due to it low specific weight and bio-compatibility.
• Aluminuim AlSi10Mg is a typical casting alloy with good casting properties, typically used for cast parts with thin walls and complex geometries.
• Stainless Steel 316L characterised for having good corrosion resistance and evidence that there are no leachable substances in cytotoxic concentrations.