DMLS (Direct Metal Laser Sintering) 3D Printing

DMLS Materials for 3D Printing

Aluminum AlSi10Mg

AlSi10Mg is a typical casting alloy with good casting properties and is used for cast parts with thin walls and complex geometry. The alloying elements silicon and magnesium lead to high strength and hardness. The alloy also features good dynamic properties and is therefore used for parts subject to high loads. Parts in Aluminum AlSi10Mg are ideal for applications which require a combination of good thermal properties and low weight.

Applications

• Direct manufacture of functional prototypes
• Small production runs
• Products or spare parts
• Automotive
• Engineering
• Motor racing
• Aerospace
• Prototype parts for aluminum die casting

Cobalt Chrome MP1

Cobalt Chrome MP1 produces parts in a cobalt-chrome-molybdenum-based superalloy. This class of superalloy is characterized by having excellent mechanical properties (strength, hardness), corrosion resistance and temperature resistance. Such alloys are commonly used in biomedical applications such as dental and medical implants and also for high-temperature engineering applications such as in aerospace engines.

Properties

• High strength, temperature and corrosion resistance
• Mechanical properties improve with increased temperature up to 500-600 °C
• Chemistry conforms to the composition UNS R31538 of high carbon CoCrMo alloy
• Nickel-free (< 0.1 % nickel content).
• Fulfils the mechanical and chemical specifications of ISO 5832-4 and ASTM F75 for cast CoCrMo implant alloys

Applications

• High-temperature engineering applications, e.g. turbines, medical implants

Maraging Steel MS1

Maraging Steel MS1 is a martensite-hardenable steel. Its chemical composition corresponds to U.S. classification 18% Ni Maraging 300, European 1.2709 and German X3NiCoMoTi 18-9-5. This kind of steel is characterized by having excellent strength combined with high toughness. The parts are easily machinable and polished after the building process and can be easily post-hardened to more than 50 HRC.

Properties

• Easily machinable
• Age hardenable up to approx. 54 HRC
• Good thermal conductivity

Applications

• Series injection molding, also for high volume production
• Other tooling applications, e.g. aluminum die casting
• High performance parts

Stainless Steel GP1

Stainless Steel GP1 is a stainless steel. Its chemical composition corresponds to U.S. classification 17-4, European 1.4542 and German X5CrNiCuNb16-4. This kind of steel is characterized by having good mechanical properties, especially excellent ductility in laser processed state and is widely used in a variety of engineering applications. This material is ideal for many part-building applications such as functional metal prototypes, small series products, individualized products or spare parts.

Properties

• Good mechanical properties
• Excellent ductility

Applications

• Engineering applications including functional prototypes
• Small series products
• Individualized products or spare parts
• Parts requiring particularly high toughness and ductility

Stainless Steel PH1

Stainless Steel PH1 is a stainless steel. The chemical composition conforms to the compositions of 15-5 PH, DIN 1.4540 and UNS S15500. This kind of steel is characterized by having excellent mechanical properties, especially in the precipitation hardened state. This type of steel is widely used in a variety of medical, aerospace and other engineering applications requiring high hardness and strength. This material is ideal for many part-building applications such as functional metal prototypes, small series products, individualized products or spare parts.

Properties

• Very high strength
• Easily hardenable up to approx. 45 HRC

Applications

• Engineering applications including functional prototypes
• Small series products
• Individualized products or spare parts
• Parts requiring particularly high strength and hardness

Titanium Ti64

Titanium Ti64 (Ti6Al4V) is a Titanium alloy. This well-known alloy is characterized by having excellent mechanical properties and corrosion resistance combined with low specific weight and biocompatibility. The ELI version (extra-low interstitials) has particularly high purity.

Properties

• Light weight with high specific strength (strength per density)
• Corrosion resistance
• Biocompatibility
• Laser-sintered parts fulfil requirements of ASTM F1472 (for Ti6Al4V) and ASTM F136 (for Ti6Al4V ELI) regarding maximum impurities
• Very good bio-adhesion

Applications

• Aerospace and engineering applications
• Biomedical implants

DMLS Finishing

Fathom can take your DMLS part to the next level by offering in house finishing options to meet your needs. We can also manage all of your outsource finishing needs of your DMLS parts. Parts “as built” off DMLS machines have a “raw” finish comparable to a fine investment cast, with a surface roughness of approximately 350 R a- µ inch or R a-µm 8.75, or a medium turned surface. This surface roughness can be improved all the way up to 1 R a- µ inch or R a-µm 0.025, qualifying as a super mirror finish. There are several processes available that can be used to achieve the desired surface roughness or finish.

Abrasive Blast (Grit & Ceramic):

Abrasive blasting is the operation of forcibly propelling a stream of abrasive material (media) against a surface under high pressure to smooth a rough surface. Abrasive blasting services are included standard for all DMLS projects. If a “raw” DMLS part is desired, this should be noted at the time of the RFQ when addressing the desired surface roughness. Abrasive blasting with grit and ceramic media provides a satin, matte finish of approximately 150 R a- µ inch or R a-µm 24. This finish is largely uniform but does not provide a 100% uniform finish.

Shot Peen:

Shot peening is a process used to produce a compressive residual stress layer and modify mechanical properties of metals. It entails the use of media to impact a surface with sufficient force to create plastic deformation. It is similar to blasting, except that it operates by the mechanism of plasticity rather than abrasion. Peening a surface spreads, it plastically, causing changes in the mechanical properties of the surface. Depending on the part geometry, part material, shot material, shot quality, shot intensity and shot coverage, shot peening can increase fatigue life from 0–1000%. Shot peening is used primarily for foundries for deburring or descaling surfaces in preparation for additional post-processing.

When projects have geometries in low quantities that are not tolerance dependent, the best finishing option is an optical polish. Optical polishes are extremely cost effective and the best way to achieve a brilliant finish. Due to surface porosity of DMLS metals, .003” to .010” of surface material is removed depending upon geometry. If this option is desired, it is imperative that designers or engineers consult with Fathom prior to building, as specific surfaces may need to be offset with additional material to ensure part integrity after post-processing. Optical polishing is not ideal for large batches as it lends itself to an inconsistent finish from part to part.

Electrochemical Polishing:

Electrochemical polishing also referred to as electro polishing, is an electrochemical process that removes material from metal parts through polishing, passivation and deburring. It is often described as the reverse of electroplating; differing from anodizing in that the purpose of anodizing is to grow a thick, protective oxide layer on the surface of a material rather than polish. The process may be used in lieu of abrasive fine polishing in micro structural preparation and is an inexpensive option for DMLS projects that are not tolerance dependent, creating a bright uniform finish. The extent to which electro polishing is successful depends upon the degree of preparation of the treated surfaces.

Abrasive Flow Machining (Extrude Hone) Polishing:

Abrasive flow machining (AFM), also known as extrude honing is a method of smoothing and polishing internal surfaces and producing controlled radii. A one-way or two-way flow of an abrasive media is extruded through a workpiece, smoothing and finishing rough surfaces. One-way systems flow the media through the workpiece, then it exits from the part. In two-way flow, two vertically opposed cylinders flow the abrasive media back and forth. The process is particularly useful for difficult to reach internal passages, bends, cavities and edges. This is an inexpensive option for DMLS projects that are not tolerance dependent and a more uniform surface roughness. The extent to which AFM is successful depends upon the degree of preparation of the treated surfaces.

Electroplating:

Electroplating is a process that uses electrical current to reduce ions of a desired material from a solution and then coat a conductive object with a thin layer of the metal material. Electroplating is primarily used for depositing a layer of metal to bestow a desired property (e.g., abrasion and wear resistance, corrosion protection, lubricity, aesthetic qualities). Another application uses electroplating to build up thickness on undersized parts. Plating is also an inexpensive method of improving surface roughness, with the reduction in roughness once again hinging upon the degree to which surface are treated prior to plating. DMLS parts can also be plated in their raw state and then finished in combination with another method.

Micro Machining Process (MMP):

Micro Machining Process (MMP) is a mechanical-physical-chemical surface treatment applied to items placed inside a treatment tank, providing highly accurate selective surface finishes. The desired surface finish is obtained by using MMP only on those areas where that particular finish is required. MMP begins with a detailed analysis of the surface state of the item to be treated, establishing the processing parameters required to meet the customer’s objectives. MMP can finely distinguish and selectively apply different primary roughness, secondary roughness and waviness profiles to surfaces. This process has selective application and is ideal for projects requiring precision tolerance finishing to a large number of parts, as well as parts with internal passages that cannot be reached by an alternate method.

CNC Finishing/Machining:

CNC finishing permits high quality contoured milling applications to achieve tight tolerances. Detail-oriented precision can be accomplished with 3-axis, 5-axis and 6-axis CNC lathes. Conventional fixed headstock and Swiss-style CNC lathes can be utilized to support complex operations such as cross drilling and cross tapping, cross milling and slotting, C-axis milling and off-center work. Proper fixturing can yield tolerances as tight as 1 micron or (.00004”). Should this post processing option be desired, pre-build planning is required to add sufficient material to machined features and surfaces so that tolerances can be met.

What are the Advantages and Disadvantages of DMLS?

The advantages of DMLS are numerous. DMLS is perfect for projects that require design freedom and rapid parts. Parts with undercuts, draft angles, cavities, tooling, jigs, rotors, fixtures and impellers are some of the pieces that can be made using DMLS. Additionally, multiple pieces such as mountings, sectioned parts and fasteners can be streamlined into a single part. DMLS has been particularly advantageous to the aerospace industry because it allows parts to be produced that were previously impossible to manufacture.

There are a few limitations to DMLS. The parts produced can be grainy. It can be time consuming to remove the metallic support structure and may require additional machining.

History of Direct Metal Laser Sintering

Direct Metal Laser Sintering was created by the Munich, Germany firm EOS. The timeline of DMLS is as follows:

• 1995: EOSINT M 250 created an additive manufacturing DMLS system to make metal tools for plastic injection molding. This was the start of rapid tooling.
• 2001: A 20 micrometer layer thickness was created by EOS for the DMLS machining. This improved part quality.
• 2004: EOSINT M 270, a commercial grade fiber laser DMLS system was introduced.
• 2007: EOSINT introduced EOS Titanium Ti64, a commercial-grade DMLS system for titanium.

DMLS 3D Printing Quote

Using Fathom for your AM project is easy. Fathom utilizes a state-of-the-art on-demand online platform that provides our clients with unlimited access to quotes and orders for prototyping and production parts. Our production team is ready to meet your needs with a wide range of rigid and flexible material options. Also, Fathom offers advanced and expedited services. Companies of all sizes trust us from medical to consumer products, electronics, automotive, aerospace and more, including 9 of the top 10 Fortune 500 companies. Receive fast DMLS quotes and quick turnaround on parts through Fathom’s SmartQuote platform.