Additive Manufacturing of DMLS Parts

Why would we want to use Direct Metal Laser Sintering (DMLS) to additively manufacture metal components? 

I have several reasons and below I will explain them to you. 

1. Reduce waste: Because DMLS builds parts directly from CAD data and doesn't cut the part with a mill from a block of material this allows you to reduce your waste costs giving your component the idea of being "green". The advantage to being a "green" process means that with little waste there is little cost. 
2. No tooling costs: This is significant cost savings, in the past you would be limited to your design to build a tool and metal injection mold your part. Imagine you only have a few hundred parts to make and pay $20,000 dollars for your tool and be limited in your design, heck no, I don't want to imagine that....Thats because I love DMLS. 
3. Freedom of design: Whats amazing about the process is the fact you can create channels within the part, this is great for conformal cooling for injection molding and or cooling of turbine blades in aerospace applications (considering most of those blades can get as hot as 1000 degrees c.). Also, depending on the component you may be able to put in undercuts that typically would be difficult to machine, this is great for the process because you can put several parts on one build tray and just walk away as they build (its not that simple as you need to remove supports etc.).
4. Little to no inventory: We call this direct digital printing, this can save you thousands if not tens of thousands of dollars on inventory. Now you can print as needed, in the past it was pay for tooling then making thousands of parts. It is so much easier now, send a PO to the service provider and then wait a few days for your part to arrive (in some cases your service provider can send your parts direct to your customer). 
5. Speed: Now with additive manufacturing of DMLS components you can receive a completed job in most cases within a week. I think we can all agree how speed is a huge advantage in today's market. 

Why are the 5 points above so great in the manufacturing industry? Its simple, you reduce cost, help automate processes and allow for design of manufacturability for direct metal laser sintering.

There have been several advocates of additive manufacturing of DMLS components as well as several companies who have already adopted this technology as their new manufacturing process. For instance; Boeing, Pratt & Whitney, Stryker, BMW, GM, Bugati and GE, just to name a few. You can read about additive manufacturing in Industry Week magazine, Economist Magazine, People Magazine and many more. Additive manufacturing is going mainstream, will you jump on board or be left behind?

Tim Ruffner

V.P. NBD / Marketing Manager

GPI Prototype & Manufacturing Services, Inc.

http://www.GPIprototype.com

Phone: 847.615.8900

Email: Timr@GPIprototype.com

Check out our YouTube Channel for Videos on DMLS and GPI
http://www.YouTube.com/GPIprototype

How Does DMLS - Direct Metal Laser Sintering Work ?

This is the questions I hear the most...Well how does DMLS work?

We have talked about the surface finish, the cost factors, the materials and now let me explain to you how the actual process works.

Are you familiar with SLA (stereolithography)? Well is very similar to that but does it in metal...

Thats it. The end.

Just Kidding....

What makes SLA and DMLS similar is that fact that both build with supports, SLA builds with supports and so does DMLS. This means that any bottom surface must be supported to the build plate. The easiest way to explain this is that if you were to slice the part into a bunch of layers then take those layers and start from the bottom and work your way to the top, you then have to stack these layers one on top of the other right? So, you have to build from something, one layer must build on top of something else whether it be a support or another layer it just cannot be free floating in air like the SLS process is.

I hear a lot well isn't it like SLS and it doesn't require supports? Nope, this is much different, the reason being is that there is stress involved, just like traditional machining there is some warping and stress. Each layer is melted locally using a fibre optic laser, so that layer can become very hot and the laser isn't zapping the whole part at once (which may be worst).

Here is how the whole DMLS process starts;

1. You start with a CAD file that is sliced into 20 or 40 micron layers using a specialized software called Magics. There is a lot more that goes into just taking the CAD file, for instance each part must be orientated to build the best way. I can't give away all the secrets right?
   
2. Take the sliced file and input it into the EOS software and depict the best angle for this part to be facing the recoater blade (the blade that sweeps new powder over each layer).
3. Output job file.
   
4. Add powder and level build plate inside the equipment.
5. Install Job parameters for the EOS equipment via the EOS software.
   
6. Input job file to the EOS equipment computer.
   
7. Let oxygen levels get to a safe amount.
8. Hit GO!
9. Take build plate out of EOS equipment.
10. Cut parts off the build plate (typically a 2-4 mm support structure under the part is cut close to the plate).
11. Remove support material with a variety of tools and/or CNC equipment.
12. Finish said parts to desired finish level.
    
13. Pack and send.
    

I made that seem very simple, however there is much more that is involved. Removing the supports isn't always the easiest thing in the world, as the support material is the same material that the part is created in. I know I am missing a ton of information but this is the easiest way to teach you how the actual process works. Stay tuned for more blog posts. I am attaching a very fun video that will help you understand DMLS. Direct Metal Laser Sintering (DMLS) Video

Tim Ruffner
V.P. NBD / Marketing Manager
GPI Prototype & Manufacturing Services, Inc.
http://www.GPIprototype.com
Phone: 847.615.8900
Email: Timr@GPIprototype.com

Check out our YouTube Channel for Videos on DMLS and GPI
http://www.YouTube.com/GPIprototype

Direct Metal Laser Sintering (DMLS)
DMLS
Sintering

DMLS in Aluminum, Inconel or Titanium - Is it worth it?

DMLS in Aluminum, Inconel or Titanium - Is it worth it?

The million dollar question right...is it really worth prototyping the exotic metals using DMLS rather than machining them. I guess it is really going to depend on your time frame and geometry. The thing about DMLS is, its super fast, on top of that it can do some crazy geometries. Would it be worth a one off CNC of a titanium or aluminum part if you have to create work-holders and buy a lot of material to do just one part, probably not. Let me talk a little about each of the exotic materials.

DMLS TITANIUM

Since DMLS is an additive technology, it drastically reduces material waste in comparison with traditional processes. Investment casting of titanium, for example, is difficult and often has a high scrap rate. Currently, many titanium aerospace components are machined from solid stock, often cutting away 90% or more of the original material – a time-consuming, costly operation that is completely eliminated with DMLS titanium not to mention much lower labor costs.

Some of the characteristics that make titanium ideal for aerospace applications also make it difficult to machine. Its hardness and low heat conductivity reduce tool speeds and life, require a great deal of liquid cooling during machining, and limit the productivity of certain shapes, such as thin walls. Laser-sintered titanium, however, retains the beneficial properties of the metal and involves no tool-wear or coolant costs. In addition, nearly any geometry, including thin walls, can be created with laser-sintering. - Nextbigfuture.com

Typical Applications:
- Direct manufacture of functional prototypes, small series products, individualized products
- Spare parts
- Parts requiring a combination of high mechanical properties and low specific weight, e.g.structural and engine components for aerospace and motor racing applications, etc.
- Biomedical implants

DMLS ALUMINUM

EOS Aluminium AlSi10Mg is a master alloy aluminium- powder. AlSi10Mg is a typical casting alloy with good casting properties and is used for cast parts with thin walls and complex geometry. The alloy combination silicon/magnesium results in a significant increase in the strength and hardness. It also features good dynamic properties and is therefore used for parts subject to high loads.Standard building parameters completely melt the powder in the entire part.
Parts made of EOS Aluminium AlSi10Mg can be machined, wire eroded and electrical discharge machined,welded, micro-blasted, polished and coated. Unexposed powder can be re-used.

Typical applications:
- Direct manufacture of functional prototypes, small production runs, user-specific products or spare parts
- Parts that require a combination of good thermal properties with low weight, e. g. for motor-sport applications

DMLS INCONEL

Try machining Inconel 718 and see how many people start yelling about that. Its tough and nobody likes to do it. Well until now. The DMLS process allows you to produce Inconel parts quick while being affordable.

This material is ideal for many high temperature applications such as gas turbine parts, instrumentation parts, power and process industry parts etc. Material also possesses excellent cryogenic properties and potential for cryogenic applications.
Standard processing parameters use full melting of the entire geometry, typically with 20 μm layer thickness. Parts built from EOS NickelAlloy IN718 can be easily post-hardened to 40-47 HRC (370-450HB) by precipitation-hardening heat treatments. In both as-built and age hardened states the parts can be machined, spark-eroded, welded, micro shot-peened, polished and coated if required. Unexposed powder can be reused.

Typical applications:
- Aero and land based turbine engine parts
- Rocket and space application components
- Chemical and process industry parts
- Oil well, petroleum and natural gas industry parts

I look forward to your comments!

Tim Ruffner
GPI Prototype & Manufacturing Services, Inc.
940 North Shore Drive
Lake Bluff, IL 60044
http://gpiprototype.com
Phone: 847.615.8900
Fax: 847.615.8920
Email: Timr@GPIprototype.com
GPI on Twitter
Tim Ruffner LinkedIn

Surface Finish & Finishing of DMLS - (Direct Metal Laser Sintering) Parts

FINISHING/POLISHING (SURFACE ROUGHNESS)
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. These processes include, but not limited to:

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.

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 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.

Optical Polish (Hand Finishing)
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.

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. MMP is a batch process that is quite expensive, with costs ranging from $500 to $1000 for sample finish testing. After acceptable samples have been provided, costs for batch runs start at approximately $3000. 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.


Cobalt Chrome MP1, media tumbled.


Cobalt Chrome MP1, optical polish #2


Cobalt Chrome MP1, optical polish (mirror finish) #3.


The shell behind the finished part is a "raw" part. You can see the contrast with this finish. This finish is the "optical finish". Stainless Steel. PH1.


This is an insert which had supports removed and abrasive blasted. MS1.


Raw with supports. Stainless Steel.


Stainless Steel PH1, shot peened finish.


Stainless Steel PH1, raw with supports removed.

Tim Ruffner
Account Executive
GPI Prototype & Manufacturing Services, Inc.
940 North Shore Drive
Lake Bluff, IL 60044
http://gpiprototype.com
Phone: 847.615.8900
Fax: 847.615.8920
Email: Timr@GPIprototype.com
GPI on Twitter
Tim Ruffner LinkedIn
*DMLS – Direct Metal Laser Sintering Blog

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DMLS -Direct Metal Laser Sintering Awesome HILARIOUS Video

http://www.youtube.com/watch?v=wjSb51aEpWU

This video is a funny take on GPI Prototype doing a DMLS Rush Order for a customer. You have to check this video out especially the ending. Comment and rate the video on Youtube. It would mean a lot to me!



GPI Prototype Direct Metal Laser Sintering - DMLS

Tim Ruffner
GPI Prototype
http://gpiprototype.com
DMLS, SLA, SLS, FDM, RTV, CNC and more Prototype Experts
timr@gpiprototype.com

GPI Prototype now on YOUTUBE

That's right

Here we are...



Tim Ruffner
Account Executive
GPI Prototype & Manufacturing Services, Inc.
940 North Shore Drive
Lake Bluff, IL 60044
http://GPIprototype.com
Phone: 847.615.8900
Fax: 847.615.8920
Email: Timr@GPIprototype.com

Conformal Cooling

Conformal Cooling
Conformal cooling is defined as the ability to create cooling/heating configurations within a tool that essentially follows the contour of the tool surface or deviates from that contour as thin/thick sections of the part may dictate for optimal thermal management. The objective typically is to cool or heat the part uniformly. Conformal cooling provides a tremendous advantage in mold tooling through significant reductions in cycle times. Other than the obvious piece-cost savings, other tangible benefits include tool, equipment and floor space savings.

Recent studies show conformal cooling may reduce cycle times between 30 to 60 percent over conventionally cooled tools. This savings is very much geometry-dependent. The more difficult thermal management is with traditional technology, the greater the opportunity for savings with conformal cooling. The Direct Metal Laser Sintering process naturally lends itself to the integration of conformal cooling into injection molds or other tooling.

It should be noted that in many cases, resurfacing the tool might not be necessary to enable the prototype tool to be used in production. Depending on the types of parts being produced, such as volume, surface requirements, abrasiveness of materials, and so on, the prototype tool may be sufficient for production as built.

Conformal Cooling PDF
Conformal Cooling Link

Cooling of injection molding tooling is crucial to the performance of the tooling, influencing both the rate of the process and the resulting quality of the parts produced. However, cooling line design and fabrication have been confined to relatively simple configurations, primarily due to the limits of the fabrication methods used to make tools, but also due to the lack of a design methodology appropriate for cooling lines.

For many years, mold designers have been struggling for the improvement of cooling system performance, despite the fact that cooling system complexity is physically limited by the fabrication capability of conventional tooling methods. Different methods such as helical channels, the baffled hole system, the spiral plug system and heat-pipes have been developed for uniform and efficient cooling of the part. Some mold manufacturers such as Innova Zug Engineering GmbH of Germany optimized the thermal conditions by building cooling channels following the part shape. Other manufacturers such as CITO Products, Inc., developed the pulse cooling technique for better control of the mold temperature, in order to reduce the energy consumption and enhance uniform cooling condition.

The emergence of new processes that can be used to create tools with conformal cooling channels placed with almost arbitrary complexity not only offers the designer new degrees of freedom in the design of injection molding tools, but also simplifies the methodology used to design cooling channels.

Conformal Cooling on the web

CLICK HERE TO LEARN HOW GPI CAN HELP YOU WITH YOUR DMLS APPLICATIONS AND CONFORMAL COOLING

Solid Freeform Fabrication processes such as DMLS have demonstrated the potential to produce tools with complex internal geometry. This work explores the application of this capability to improve thermal management for injection molding tooling through: (i)cooling lines which are conformal to the mold surface which provide improved uniformity and stability of mold temperature and (ii)tools with low thermal inertia which, in combination with conformal fluid channels allow for rapid heating and cooling of tooling, thereby facilitating isothermal filling of the mold cavity. This work presents a systematic, modular, approach to the design of conformal cooling channels. Recognizing that the cooling is local to the surface of the tool, the tool is divided up into geometric regions and a channel system is designed for each region. Each channel system is itself modeled as composed of cooling elements, typically the region spanned by two channels. Six criteria are applied including; a transient heat transfer condition which dictates a maximum distance from mold surface to cooling channel, considerations of pressure and temperature drop along the flow channel and considerations of strength of the mold. These criteria are treated as constraints and successful designs are sought which define windows bounded by these constraints. The methodology is demonstrated in application to a complex core and cavity for injection molding. In the area of rapid thermal cycling, this work utilizes the design methods for conformal channels for the heating phases and adds analysis of the packing and cooling phases. A design is created which provides thermal isolation and accommodation of cyclic thermal stresses though an array of bendable support columns which support the molding portion of the tool where the heating/cooling channels are contained. Designed elasticity of the tool is used to aid in packing of the polymer during the cooling phase.

Conformal Cooling Research from NASA and MIT

DMLS on Video

It will be just a matter of days before I put the DMLS video on youtube. I am going to run a short series along with some several key points in regards to additive manufacturing.

-GPI Into Video
-DMLS - Direct Metal Laser Sintering Process
-Conformal Cooling - The process that can save injection molders at least 30% cycle time.

I will put up the links so they can be followed and hope to see you all watching.

Direct Metal Laser Sintering

Process

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, automatically, without tooling. The parts have excellent mechanical properties, high detail resolution and exceptional surface quality. The process melts the metal powder entirely, creating a fine, homogenous structure.

Benefits

DMLS enables the formation of cavities and undercuts which, with conventional 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. 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.

Tim Ruffner

Account Executive

GPI Prototype & Manufacturing Services, Inc.

940 North Shore Drive

Lake Bluff, IL 60044

http://www.GPIprototype.com

Phone: 847.615.8900

Fax: 847.615.8920

Email: Timr@GPIprototype.com