#stereolithography

Big Bug

As part of my studies, I had the opportunity to use a 3D printer for the first time in my life. We were allowed to choose a model and the process.

Creating stronger and more ductile microlattice materials with reduced unit sizes

Projection micro stereolithography (PμSL) has emerged as a powerful three-dimensional (3D) printing technique for manufacturing polymer structures with micron-scale high resolution at high printing speed, which enables the production of customized 3D microlattices with feature sizes down to several microns. However, the mechanical properties of as-printed polymers were not systemically studied at the relevant length scales, especially when the feature sizes step into micron/sub-micron level, limiting its reliable performance prediction in micro/nanolattice and other metamaterial applications.

Based on self-developed in situ micro-mechanical platform, Prof. Yang Lu from City University of Hong Kong demonstrates that projection micro-stereolithography (PμSL)-printed microfibers could become stronger and significantly more ductile with reduced size ranging from 20 μm to 60 μm, showing an obvious size-dependent mechanical behavior, in which the size decreases to 20 μm with a fracture strain up to ~100% and fracture strength up to ~100 MPa.

Such size effect enables the tailoring of the material strength and stiffness of PμSL-printed microlattices over a broad range, allowing to fabricate the microlattice metamaterials with desired/tunable mechanical properties for various structural and functional applications.

Sleestak STL

Did you know that this extraordinary, 2.5 meter-long, 3D-printed model is an accurate snapshot of what the Belgian coastline looked like during WW1?

It was based on aerial photographs of the time and each detail was painstakingly recreated in 3D.

When walking along the Belgian coast today, you would never guess that 100 years ago it was the scene of one of the bloodiest wars in European history: World War I. Only a few traces remain – in Raversijde, you can spot bunkers peeking out from the dunes, including, if you look closely, some remaining coastal artillery. The Atlantikwall Museum in Raversijde allows visitors to immerse themselves in the atmosphere of WWI, and a new exhibition about munition in WWI will bring the coastline of 1914 even more to life. The star of the exhibition is a massive, highly detailed, 3D-printed model which is an exact replica of the coastline as it was during the war.

TO THE POINT – VMZINC’s column

Additive manufacturing: the fourth industrial revolution!

About ten years ago, it was predicted that forthcoming industrial revolutions would be continuously occurring on an unprecedented scale. Our sector of activity, construction, is also experiencing these unbridled technological evolutions. Without the general public really being aware of the revolutions that are underway in terms of building design and production, or the amazing capacity for intellectual and structural adaptation of the entire chain of professionals concerned.

3D Printers: are they really still just printers?

I wrote a Post in 2015 on the subject of 3D printers and their potential for development (post 18: “3D printers: breakthrough innovation for the construction industry”).

This sector is rapidly evolving. It has already reached series production level, with the production of corrective glasses made of composite material, and manufacture of small ceramic bricks.

Two trends are emerging: firstly, the size of the objects being manufactured is constantly increasing and secondly, new materials are being tested on a daily basis. So the traditional melted plastic thread is facing competition from concrete, aluminium, steel, cobalt-chrome, titanium, ceramic and composite wood. With particular attention given to recycled materials (recycled plastic granules, sawdust with binding agents, conversion of food waste, etc.)

The term “3D printer” is now replaced by “additive manufacturing”, which simply means that, under the control of a computer, the object is built by depositing layerupon layer of material, or by solidification. As opposed to subtractive manufacturing, where material is removed to create the desired form, where the mass is cut into and therefore loses material, this “additive manufacturing” makes it possible not just to produce components effectively but also to create small series of new components that are even more innovative, which previously could not be done (in the automotive and aerospace sectors for example).  Strictly speaking, these additive manufacturing processes are not all actually “printing”, hence the semantic change. So what in fact is this?

 Four additive manufacturing  techniques

- Fuse Deposition Modelling (FDM): This is what is now called the “general public” printing technique using thermoplastic polymers

 -  Selective Laser Sintering (SLS): Selective sintering by laser using powder fused by energy from a high power laser, enabling plastic or nylon to be mixed with carbon or glass fibres to give greater rigidity. This technique is used for ceramic and certain metals.

 -  Stereolithography, which consists of controlled solidification of a liquid plastic material by laser.

-  Selective Deposition Laminating, with laser cutting of successive layers that are subsequently stacked (paper, plastic or even metal bases).

In Dubai in 2016, offices were built using large plastic shells assembled on site (see link below). In the United States, concrete houses with a ground surface area of 225 m² were built in 24 hours!

http://www.numerama.com/sciences/173099-dubai-a-construit-premiers-bureaux-impression-3d.html

 Architects and designers at the heart of this 4th industrial revolution

Architects have understood that 3D printers can play a significant role in the production of their models, especially when the latter represent buildings with complex forms. This is the end of the road for models made with wood, glue and foamboard! More generally speaking, additive manufacturing will become an incomparable tool for computer assisted design and decision making in architecture firms. It will accelerate the conceptual research phase, while at the same time simplifying it.

And what about Mathias Bengtsson, the Danish designer who took it into his head to work with his 3D printer using software simulating organic growth and incorporating hundreds of parameters in terms of mass, energy, gravity and pressure loads?  This process enabled him to produce a table with successive layers of titanium fused by an electron beam via the EBM technique (Electron Beam Melting) used in aeronautics.

https://www.youtube.com/watch?v=RPYrg0dTmD8

 In industrial circles, the term used is “increased” manufacturing

One might think that additive will mainly take off for production of parts and components to sell as they are, or integrated into mass distribution products. Industrials are talking about “alternative” manufacturing that diversifies and complements traditional series production. This is already the case in the aeronautics industry. Airbus is already using this technology to develop hundreds of components for its A350 programme. PSA Group is already producing some components (interior door handles at Peugeot).

But it would appear that in the short term, the main focus is on production via the method of adding tools, in particular templates and fixing used on production lines. Products that we don't see but that are decisive for the reliability of these lines. This is what industrials refer to as “increased manufacturing”. It has been demonstrated that replacing wear parts that are often expensive  (small series) and lengthy to obtain (artisanal manufacturing) can be revolutionised by 3D printers, which therefore drastically reduce costs.

If there is a real economic advantage to be had, it will work… and it's already working!  

 VMZINC

Director of VMZINC communication