GPI Prototype is a service provider of Direct Metal Laser Sintering (DMLS), also commonly known as metal 3d printing. As one of the first DMLS rapid prototyping service providers in the country, GPI produces metal parts for applications ranging from prototypes to production. DMLS technology is ideal for a variety of applications including the creation of conformal cooling channels for injection molding tooling.
Utilizing the DMLS process, metal parts of the most complex geometries are built layer-by-layer (down to 20 microns) directly from 3D CAD data. Parts built using a DMLS printer have excellent mechanical properties equivalent to wrought materials, high detail resolution, and exceptional surface quality. The metal powder is melted entirely to create a fully dense, fine, homogenous structure. Unique geometric freedom of design enables DMLS to form cavities and undercuts, which with conventional machining methods, can only be produced with great difficulty, if at all.
Additionally, when a part needs to be tested and re-designed over and over, the lead time for receiving a traditionally tooled part can create a large bottleneck in the final production process. DMLS produces parts that are extremely high quality and can be built in a matter of hours or days rather than weeks. The ability to generate functional metal prototypes in short order radically impacts design processes, accelerating design cycles and time to market.
Depending on size and geometries, in some cases the turnaround time for a part can be as little as a few hours. Furthermore, these parts can undergo functional testing in the environment for which they were designed. This technology delivers unlimited potential for engineers to create previously impossible solutions, embracing a new era of design-driven manufacturing.
GPI Prototype currently has six DMLS machines at our Lake Bluff, Illinois facility. There are six machines from EOS including two EOSINT M 270 machines, two EOSINT M 280 machines, and two EOSINT M 290 machines.
EOSINT M 290
The EOSINT M 290 is an updated and improved version of the EOSINT M 280, an additive layer manufacturing system for metal components. It builds high quality metal parts from 3D CAD data, layer by layer, by melting fine metal powder with a laser. The layered approach enables the creation of extremely complex geometries that wouldn't be possible with CNC machining, including deep groves and three-dimensional cooling channels.
The system is equipped with a 400 watt laser which provides exceptionally high quality parts during the building process. The system operates in both protective nitrogen and argon atmospheres, allowing a wide range of materials to be used including: light metals, stainless steel, tooling steel and super alloys. The EOSINT M 290 offers a number of powdered metal materials with corresponding parameter sets and standardized property profiles. In addition, all materials are subjected to an intensive process development procedure and constant quality assurance.
The M290 has a build volume of 9.85 x 9.85 x 12.8" or 250 x 250 x 325 mm including the build platform, allowing taller parts to be built compared to the EOSINT M280.
EOSINT M 280
The EOSINT M 280 is an updated and improved version of the EOSINT M 270, an additive layer manufacturing system for metal components. It builds high quality metal parts from 3D CAD data fully automatically, with no need for tools. The system builds parts up layer by layer by melting fine metal powder with a laser, enabling the creation of extremely complex geometries. Parts can be made that wouldn't be possible with CNC machining, including deep groves and three-dimensional cooling channels.
The system is equipped with a solid state 200 watt laser which provides exceptionally high quality parts during the building process. The system operates in both protective nitrogen and argon atmospheres, allowing a wide range of materials to be used including: light metals, stainless steel, tooling steel and super alloys. The EOSINT M 280 offers a number of powdered metal materials with corresponding parameter sets and standardized property profiles. In addition, all materials are subjected to an intensive process development procedure and constant quality assurance.
EOSINT M 270
The M270 is an additive layer manufacturing system for metal components. It builds high quality metal parts from 3D CAD data fully automatically, with no need for tools. The system builds parts up layer by layer by melting fine metal powder with a laser, enabling the creation of extremely complex geometries. Parts can be made that wouldn't be possible with CNC machining, including deep groves and three-dimensional cooling channels. Innovative companies are using this technology for fast, flexible, cost-effective prototypes, series production parts or even spare parts.
DMLS is a well know leading technology for toolmaking. With its high accuracy and surface quality the system is ideal for building tool inserts. The freedom of design allowed by this additive manufacturing process allows for conformal cooling channels to be integrated into parts to reduce injection molding cycling times by up to 75%. This direct process eliminates tool-path generation and multiple machining processes such as EDM. The process is mainly used for injection molding, however it can also be used for other tooling types including blow moulding, extrusion, die casting, sheet metal forming, etc.
The system is equipped with a solid state 200 watt laser which provides exceptionally high quality parts during the building process. The system operates in a protective nitrogen atmosphere, allowing a wide range of materials to be used ranging from light alloys via steels to super-alloys and composites. The EOSINT M 270 offers a number of powdered metal materials with corresponding parameter sets and standardized property profiles. In addition, all materials are subjected to an intensive process development procedure and constant quality assurance.
|Stainless Steel (PH1)
||15-5 PH, DIN 1.4540 and UNS S15500
||20 or 40 Micron Layers
||30-35 HRC Built, Post Hardened to 40 HRC
||High Hardness & Strength
||Prototype / Production Parts
|Stainless Steel (GP1)
||17-4, European 1.4542, German X5CrNiCuNb16-4
||20 or 40 Micron Layers
||230 ± 20 HV1 Built, Ground & Polished to 250-400 HV1
||High Toughness & Ductility
|Cobalt Chrome (MP1)
||ISO 5832-4 and ASTM F75
||20, 40 or 50 Micron Layers
||35-45 HRC Built
||High Temperature Resistance
||Turbines & Engine Parts
|Maraging Steel (MS1)
||18% Ni Maraging 300, European 1.2709, German X3NiCoMoTi 18-9-5
||20 or 40 Micron Layers
||33-37 HRC Built, Post Hardened to 50-56 HRC
||Easily Machinable & Excellent Polishability
||Injection Molding Tooling, Conformal Cooling
||Typical Casting Alloy
||30 Micron Layers
||Approx 119 ± 5 HBW
||Low Weight, Good Thermal Properties
||UNS N07718, AMS 5662, AMS 5664, W.Nr 2.4668, DIN NiCr19Fe19NbMo3
||40 Micron Layers
||30 HRC Built, Post Hardened 47 HRC
||Heat & Corrosion Resistant
||Turbines, Rockets, Aerospace
|Stainless Steel (316L)
||20 Micron Layers
||Corrosion & Pitting Resitant
||Surgical Tools, Food & Chemical Plants
||30 or 60 Micron Layers
||320 ± 15 HV5
||Light Weight, High Strength, Corrosion resistance
||Aerospace, Motorsport Racing
|Titanium Ti-64 ELI
||ASTM F136 Properties
||30 or 60 Micron Layers
||320 ± 15 HV5
||Corrosion Resistance, Biocompatibility
||Medical, Biomedical, Implants
GPI can take your DMLS part to the next level by offering in house finishing levels 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 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 GPI 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 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 is a process that uses electrical current to reduce ions of a desired material from a solution and 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, etc.). 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 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.