Tiny but fully functional! Industrial 3D printed micro parts

We currently witness a trend towards miniaturization and an increasing significance of highly precise micro parts in nearly all industries. As a result, an ever increasing demand for miniaturized, highly productive parts more and more also has an impact on product development. These often very filigree parts allow for only very narrow tolerances that cannot be surpassed. As well, these parts should be designed in a way to bear up even long-term stress.

As a reply to these market challenges EOS has developed the Micro Laser-Sintering (MLS) Technology and offers all benefits of an Additive Manufacturing (AM) process for the e-manufacturing of miniaturized parts. EOS not only supports its clients in the development of new application areas but as well provides the infrastructure to enable a series production of micro parts. MLS can be a solution, if a client is aiming for small, complex or individualized parts; if a large surface is needed within a small volume; if a client wants to achieve small light-weight build metal parts; or if a high-melting material is needed.  

Already today, there are a lot of application areas for micro technologies, growing constantly. Particularly in medical technology, electrical and electronic industry as well as in automotive EOS expect an increasing demand. Of particular interest are micro moulded parts, micro eroding moulds and micro fluid mixer. Even the jewellery industry more and more sees the benefits of this process. As well, applications such as sensors, micro valves, and mechanical transmission elements are possible areas of interest for MLS. At EOS, MLS is constantly being further developed. For this, EOS cooperates with selected partners. 

Fabrication of scalable and structured tissue engineering scaffolds using water dissolvable sacrificial 3D printed moulds

Abstract

One of the major challenges in producing large scale engineered tissue is the lack of ability to create large highly perfused scaffolds in which cells can grow at a high cell density and viability. Here, we explore 3D printed polyvinyl alcohol (PVA) as a sacrificial mould in a polymer casting process. The PVA mould network defines the channels and is dissolved after curing the polymer casted around it. The printing parameters determined the PVA filament density in the sacrificial structure and this density resulted in different stiffness of the corresponding elastomer replica. It was possible to achieve 80% porosity corresponding to about 150 cm²/cm³ surface to volume ratio. The process is easily scalable as demonstrated by fabricating a 75 cm³ scaffold with about 16,000 interconnected channels (about 1 m² surface area) and with a channel to channel distance of only 78 μm. To our knowledge this is the largest scaffold ever to be produced with such small feature sizes and with so many structured channels. The fabricated scaffolds were applied for in-vitro culturing of hepatocytes over a 12-day culture period. Smaller scaffolds (6 × 4 mm) were tested for cell culturing and could support homogeneous cell growth throughout the scaffold. Presumably, the diffusion of oxygen and nutrient throughout the channel network is rapid enough to support cell growth. In conclusion, the described process is scalable, compatible with cell culture, rapid, and inexpensive.

LINK

Fabrication of scalable and structured tissue engineering scaffolds using water dissolvable sacrificial 3D printed moulds

Abstract

One of the major challenges in producing large scale engineered tissue is the lack of ability to create large highly perfused scaffolds in which cells can grow at a high cell density and viability. Here, we explore 3D printed polyvinyl alcohol (PVA) as a sacrificial mould in a polymer casting process. The PVA mould network defines the channels and is dissolved after curing the polymer casted around it. The printing parameters determined the PVA filament density in the sacrificial structure and this density resulted in different stiffness of the corresponding elastomer replica. It was possible to achieve 80% porosity corresponding to about 150 cm²/cm³ surface to volume ratio. The process is easily scalable as demonstrated by fabricating a 75 cm³ scaffold with about 16,000 interconnected channels (about 1 m² surface area) and with a channel to channel distance of only 78 μm. To our knowledge this is the largest scaffold ever to be produced with such small feature sizes and with so many structured channels. The fabricated scaffolds were applied for in-vitro culturing of hepatocytes over a 12-day culture period. Smaller scaffolds (6 × 4 mm) were tested for cell culturing and could support homogeneous cell growth throughout the scaffold. Presumably, the diffusion of oxygen and nutrient throughout the channel network is rapid enough to support cell growth. In conclusion, the described process is scalable, compatible with cell culture, rapid, and inexpensive.

What is Additive Manufacturing?

Additive Manufacturing (AM) is an appropriate name to describe the technologies that build 3D objects byadding layer-upon-layer of material, whether the material is plastic, metal, concrete or one day…..human tissue.

Common to AM technologies is the use of a computer, 3D modeling software (Computer Aided Design or CAD), machine equipment and layering material.  Once a CAD sketch is produced, the AM equipment reads in data from the CAD file and lays downs or adds successive layers of liquid, powder, sheet material or other, in a layer-upon-layer fashion to fabricate a 3D object.

The term AM encompasses many technologies including subsets like 3D Printing, Rapid Prototyping (RP), Direct Digital Manufacturing (DDM), layered manufacturing and additive fabrication.

AM application is limitless. Early use of AM in the form of Rapid Prototyping focused on preproduction visualization models. More recently, AM is being used to fabricate end-use products in aircraft, dental restorations, medical implants, automobiles, and even fashion products.

While the adding of layer-upon-layer approach is simple, there are many applications of AM technology with degrees of sophistication to meet diverse needs including:

+ a visualization tool in design
+ a means to create highly customized products for consumers and professionals alike
+ as industrial tooling
+ to produce small lots of production parts
+ one day….production of human organs

At MIT, where the technology was invented, projects abound supporting a range of forward-thinking applications from multi-structure concrete to machines that can build machines; while work at Contour Crafting supports structures for people to live and work in.

Some envision AM as a compliment to foundational subtractive manufacturing (removing material like drilling out material) and to lesser degree forming (like forging). Regardless, AM may offer consumers and professionals alike, the accessibility to create, customize and/or repair product, and in the process, redefine current production technology.

Whether simple or sophisticated, AM is indeed AMazing and best described in the adding of layer-upon-layer, whether in plastic, metal, concrete or one day…human tissue”.

Examples of Additive Manufacturing (AM)

+ SLA
Very high end technology utilizing laser technology to cure layer-upon-layer of photopolymer resin (polymer that changes properties when exposed to light).

The build occurs in a pool of resin. A laser beam, directed into the pool of resin, traces the cross-section pattern of the model for that particular layer and cures it. During the build cycle, the platform on which the build is repositioned, lowering by a single layer thickness. The process repeats until the build or model is completed and fascinating to watch. Specialized material may be needed to add support to some model features. Models can be machined and used as patterns for injection molding, thermoforming or other casting processes.

+ FDM
Process oriented involving use of thermoplastic (polymer that changes to a liquid upon the application of heat and solidifies to a solid when cooled) materials injected through indexing nozzles onto a platform. The nozzles trace the cross-section pattern for each particular layer with the thermoplastic material hardening prior to the application of the next layer. The process repeats until the build or model is completed and fascinating to watch. Specialized material may be need to add support to some model features. Similar to SLA, the models can be machined or used as patterns. Very easy-to-use and cool.

+ MJM
Multi-Jet Modeling is similar to an inkjet printer in that a head, capable of shuttling back and forth (3 dimensions-x, y, z)) incorporates hundreds of small jets to apply a layer of thermopolymer material, layer-by-layer.

+3DP
This involves building a model in a container filled with powder of either starch or plaster based material. An inkjet printer head shuttles applies a small amount of binder to form a layer. Upon application of the binder, a new layer of powder is sweeped over the prior layer with the application of more binder. The process repeats until the model is complete. As the model is supported by loose powder there is no need for support. Additionally, this is the only process that builds in colors.

+ SLS
Somewhat like SLA technology Selective Laser Sintering (SLS) utilizes a high powered laser to fuse small particles of plastic, metal, ceramic or glass. During the build cycle, the platform on which the build is repositioned, lowering by a single layer thickness. The process repeats until the build or model is completed. Unlike SLA technology, support material is not needed as the build is supported by unsintered material

Additive Manufacturing Methods

Additive Manufacturing refers to a process by which digital 3D design data is used to build up a component in layers by depositing material. The term "3D printing" is increasingly used as a synonym for Additive Manuafcturing. However, the latter is more accurate in that it describes a professional production technique which is clearly distinguished from conventional methods of material removal. Instead of milling a workpiece from solid block, for example, Additive Manufacturing builds up components layer by layer using materials which are available in fine powder form. A range of different metals, plastics and composite materials may be used.

The technology has especially been applied in conjunction with Rapid Prototyping - the construction of illustrative and functional prototypes. Additive Manufacturing is now being used increasingly in Series Production. It gives Original Eqipment Manufacturers (OEMs) in the most varied sectors of industrythe opportunity to create a distinctive profile for themselves based on new customer benefits, cost-saving potential and the ability to meet sustainability goals.

BenefitsThe strengths of Additive Manufacturing lie in those areas where conventional manufacturing reaches its limitations. The technology is of interest where a new approach to design and manufacturing is required so as to come up with solutions. It enables a design-driven manufacturing process - where design determines production and not the other way around. What is more, Additive Manufacturing allows for highly complex structures which can still be extremely light and stable. It provides a high degree of design freedom, the optimisation and integration of functional features, the manufacture of small batch sizes at reasonable unit costs and a high degree of product customisation even in serial production.

Functional PrincipleThe system starts by applying a thin layer of the powder material to the building platform. A powerful laser beam then fuses the powder at exactly the points defined by the computer-generated component design data. The platform is then lowered and another layer of powder is applied. Once again the material is fused so as to bond with the layer below at the predefined points. Depending on the material used, components can be manufactured using stereolithography, laser sintering or 3D printing. EOS Additive Manufacturing Technology based on laser sintering has been in existence for over 20 years.

https://www.youtube.com/watch?v=F84MG_Q7X8Q

3D Printing Applications:

3D printing has been used to create car parts, smartphone cases, fashion accessories, medical equipment and artificial organs. Charles “Chuck” Hull created the first functional 3D printer in 1984 and the technology has come a long way ever since then. Manufacturing corporations and aerospace organizations have saved billions of dollars by using 3D printing for building parts. 3D printing has also helped save lives. One of the best ways to learn about what 3D printing can do is by researching real-life applications on the technology. Below are 6 creative examples of 3D printing uses:

Korean Doctors Successfully Implant 3D Printed Pelvis:

This week, Dr. Shen Tongya, professor of Neurosurgery at Yonsei University in South Korea, successfully completed a 3D printed pelvic implantation for a teenage girl suffering from one of the most common types of bone cancer.There is one ‘simple’ treatment for bone cancer, and that is to completely remove the tumor in and near the bones. Initially, Dr Tongya planned to work with radiation oncology and orthopedic bone specialists for the surgical procedure. However, because of the patient’s young age, the team led by Dr Tongya came to a consensus that traditional methods of bone cancer tumor removal would be harmful to a teenager, and may affect her mobility.

Instead, Dr Yonya decided to implement 3D printing technology and create the first 3D printed pelvis in South Korea. Due to the 3d printed pelvis, the total operation hours decreased from the typical 8 to 9 hours to a total of six hours, and the patient recovered much faster than others from the surgery.

Dr Tonya said, “The patient’s spine looks exactly how it should, thanks to the custom prosthetic implant. She has made a quick recovery and shape of her spine has been preserved.”

This has been the second major use case of 3D printing technology since the development of 3D printed titanium pelvis prosthesis back in November of 2014. The advantages of using 3D printed prosthesis or sections during surgery is its flexibility and its customable nature. In operations like bone tumor removal or implantation which require at least 8 hours of operation hours, time is crucial. 3D printed implants help surgeons to create a perfectly fit body part that is fairly easy to replace, and therefore cuts the operation time significantly.

3D Printing:

3D printing, also known as additive manufacturing (AM), refers to various processes used to synthesize a three-dimensional object.^[1]In 3D printing, successive layers of material are formed under computer control to create an object.^[2] These objects can be of almost any shape or geometry and are produced from a 3D model or other electronic data source. A 3D printer is a type of industrial robot.

Futurologists such as Jeremy Rifkin^[3] believe that 3D printing signals the beginning of a third industrial revolution,^[4] succeeding theproduction line assembly that dominated manufacturing starting in the late 19th century. Using the power of the Internet, it may eventually be possible to send a blueprint of any product to any place in the world to be replicated by a 3D printer with "elemental inks" capable of being combined into any material substance of any desired form.

3D printing in the term's original sense refers to processes that sequentially deposit material onto a powder bed with inkjet printer heads. More recently, the meaning of the term has expanded to encompass a wider variety of techniques such as extrusion and sintering-based processes. Technical standards generally use the term additive manufacturing for this broader sense.

What is 3D Printing?

It is a process of joining materials to make objects from 3D model data, usually layer upon layer, as opposed to subtractive manufacturing methodologies.

Working Principle?

It is a process of joining materials to make objects from 3D model data, usually layer upon layer, as opposed to subtractive manufacturing methodologies.

Various types of 3D Printing.

There are various types of 3D Printing exits but following are the most popular among them.

1. Selective Laser Sintering
2. Stereolithography
3. Fused Deposition Modelling
4. Laminated Object Manufacturing

All are 3D printing techniques but they mainly differentiate from each other on the basis of material that has been used in it.

Selective laser sintering (SLS)

Stereolithography

Fused deposition modeling (FDM)

Laminated object manufacturing

Applications of 3D Printing?

Tooling and Patterns:

 Rapid Tooling /Injection Mold Inserts  Investment Casting Patterns/Jigs and Fixtures

Biomedical:

Scaffold Fabrication:  Stereolithography  has been used as a fabrication technique to fabricate scaffold structures.