Direct Metal Laser Sintering

What is Metal 3D Printing?

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.

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How Does Metal 3D Printing Work?

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.

Why Choose DMLS For Your 3D Printing Project?

DMLS materials are generally accepted to be equal or better than those of wrought materials. DMLS is also ideal when the geometry or structure of the part is not possible in any other process (for weight saving designs using honeycomb or latice structures for example). Protolabs can also produce parts for implant medical applications. We also offer a number of secondary services such as painting, post machining and measurement and inspection, to further enhance the finish of your 3D-printed project design. 

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

What is Industrial 3D Printing?

Proto Labs is the world's fastest source for custom prototypes and low-volume production parts. Our high-speed 3D printing service uses advanced 3D printing technologies to create parts ranging from highly complex prototypes to functional, end-use parts. A range of plastic and metal materials are available through three additive processes: stereolithography (SL), selective laser sintering (SLS) and direct metal laser sintering (DMLS). Get 1 to 50+ parts in as fast as one day with 3D printing at Proto Labs.

Watch: Multi Jet Fusion: What is it Used For?

For fast, quality results, Multi Jet Fusion (MJF) is unparalleled as a 3D printing process. It’s able to produce functional nylon prototypes and end-use production parts in a single day, featuring quality surface finishes and fine feature resolution. It also offers more consistent mechanical properties than similar processes like selective laser sintering.

Using an inkjet array to repeatedly apply fusing agents across a bed of nylon powder, followed by fusion into a solid layer via heating elements, MJF is able to offer complex and detailed features. Protolabs offers a commercial-grade unfilled Nylon 12 material to create durable parts. Multi Jet Fusion offers a fast and advanced way to create parts on demand. Discover more with this short video.

Design Guidelines: Direct Metal Laser Sintering

Metal 3D Printing Material Options

Compare Material Properties

15 and 20 μm = high resolution (HR)
30 and 60 μm = normal resolution (NR)

These figures are approximate and dependent on a number of factors, including but not limited to, machine and process parameters. The information provided is therefore not binding and not deemed to be certified. When performance is critical, also consider independent lab testing of additive materials or final parts.

Production Capabilities for Metal 3D Printing

Looking for an additive manufacturing solution for production projects? With our metal 3D printing technology, you’re able to choose from several secondary processes like post-process machining, tapping, reaming, and heat treatments that produce end-use production parts. To ensure high-quality parts, we also offer powder analysis, material traceability, process validation, and inspection reporting, and our direct metal laser sintering (DMLS) 3D printing process is ISO 9001 and ISO 13485 certified. It’s industrial 3D printing designed around your project needs—whether prototyping or production.

1. Expertise
Consultative quoting and design feedback from our experienced engineering team and reliability from a manufacturer that has 3D printed millions of unique geometries over the last two decades.

2. Project Management
Dedicated project management support for all of your production needs from part design to finishing processes.

3. Scale
More than 100 industrial-grade metal and polymer 3D printers across five additive manufacturing technologies supporting production projects in various engineering-grade materials.

4. Quality
Rigorous process controls and engineering staff focused on achieving parts with tight tolerances, dimensional accuracy, and robust mechanical properties.

Post-Process Machining

Achieve tight tolerances while having the design freedom of additive manufacturing.

• 3- and 5-axis milling
• Turning
• Wire EDM
• Tapping

Powder Analysis & Material Traceability

Analysis of powder and traceability of the supplier to meet your production requirements. 

• Traceability
• Chemistry
• Particle size and distribution analysis

Mechanical Testing

Certified testing to confirm mechanical requirements on production parts.

• Tensile
• Hardness Testing
• Fatigue
• Vibration

Heat treatments

Specialised heat treatment processes improve the mechanical properties of parts by relieving internal stresses that develop during the sintering process. 

• Stress relief
• Hot isostatic pressing (HIP)
• Solution annealing
• Aging

Quality Inspections & Reports

Validate part geometry and evaluate material structure for quality reporting.

• Dimensional inspections with report
• First article inspection (FAI)
• CMM, optical, and CT scanning
• X-ray
• Surface roughness and porosity analysis
• Certificate of compliance with parts tracking

Certifications

Benefits of Metal 3D Printing

• 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

What is Metal 3D Printing used for?

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.

Metal 3D Printing Design Considerations

• 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.
• CuNi2SiCr is a low alloy copper, it's a material that can be used in harsh environments, whereas this is not feasible with pure copper.
• 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.

Resources

Design Tip

How DMLS is a Reliable Additive Alternative for Complex Metal Parts

Why DMLS is a Reliable Additive Alternative for Complex Metal Parts

Read Design Tip

White Paper

3D Printing Technologies for Prototyping and Production

3D Printing Technologies for Prototyping and Production

Read White Paper

Webinar

Designing for the DMLS Process

We share our technical insights about how to design parts effectively for manufacture with DMLS

Watch Webinar

Case Study

ISAR Gears

ISAR is only too happy to take on the challenging demand for electric drives in Aerospace Engineering - with expert knowledge and support from Protolabs.

Read Case Study

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