It's not just hype – 3D printing is the bridge to the future

June 19, 2015 by Iain Todd, The Conversation
‘Here I am, the most intelligent robot in the galaxy, welding a bridge.’ Credit: Heijmans

A company in the Netherlands is building a bridge across a canal in Amsterdam using 3D-printing robots. It seems that such attention-grabbing headlines appear regularly to declare how 3D-printing is destined to revolutionise manufacturing of all kinds. If the idea that key manufacturing products such as cars, aircraft – or indeed bridges – built by 3D printing sounds like hype, you're mistaken.

It's human nature to be suspicious of new things: we find them both attractive and worrying. The manufactured world around us has been made by cutting and casting and forging for many centuries. We are very comfortable with those processes and we believe that engineers and scientists can exert complete control over them, using these technologies to create the safe and predictable world (on an engineering level at least) we inhabit. This new way of making through 3D printing, in contrast, seems to have appeared suddenly and, somewhat reminiscent of the way it creates, almost out of thin air.

3D printing, or additive manufacturing as it's also known, has in fact been in use since the 1980s, beginning as a means of prototyping objects through various stages of development. Decades later, we have gained a huge wealth of knowledge and understanding of how the process works. We may marvel at the wonder of it all – and the weird and wonderful shapes that can be created through 3D printing. But the main concern for many is that the properties of 3D-printed materials are equal to their conventionally manufactured equivalents.

To answer this concern, generally speaking a 3D-printed component can have comparable properties to one made conventionally. For example, some surgical implants are already made in this way. Many people have a 3D-printed hip implant, for example, and we know that 3D-printed parts have been a feature of Formula 1 cars and military aircraft for years – and perform very well in those applications. What we are seeing now is that the technology is becoming more mainstream – and that change is helping drive a huge explosion of creative thought about how, and where, we make things.

Many of the more ambitious ideas about large-scale 3D printing emerge from laboratories and studios of artists and architects who see this as an opportunity to give their ideas physical form, enabling bespoke creations using free-form fabrication. Take for example this bridge in Amsterdam using torch-wielding robot welders: the company behind the project, MX3D, which was formed by Dutch architect and designer Joris Laarman, demonstrated its technology last year and has shown the courage of its convictions in performing this "research" in public.

Aerospace is another great supporter of emerging technologies, and large aerospace companies and supply chains are very clear that they intend to employ 3D printing as a means to manufacture airframes and engine components. In the US, GE, Lockheed Martin and Pratt and Whitney, and Airbus, Rolls Royce and GKN Aerospace in Europe have all made recent investments and announcements of products that employ 3D printing in the direct manufacture of complex components. It's even a technique used for the manufacture of spacecraft.

Despite all these high-profile, major industrial users there is a feeling among many, still, that 3D printing is all hype that will blow over soon – that there is an element of the Emperor's New Clothes about it.

If I were to draw a comparison with another field: in 2001 just as the internet was truly taking off worldwide, the author Douglas Adams made a radio programme called the Hitchhiker's Guide to the Future in which he recalled a number of conversations with those working in publishing, music and broadcasting. They were interested to know what impact the emergence of computers would have on their industries – clearly hoping, he said, that the answer would be "not very much". Of course 15 years on we know just what a significant impact digitisation and the internet has had – changing business models, consumer behaviour and expectations beyond imagination.

The reality is that we don't know where 3D printing will lead us but its potential to change the way we manufacture the things we use in our lives is enormous. As with those in Adams' programme, perhaps hoping that the impact of this emerging technology will also be "not very much" is not the right approach. Instead, as with the revolutionary effects it has had on the media, embracing the opportunities it affords us as manufacturers could take us in directions we hadn't previously considered possible

Explore further: MX3D is to 3D-print a steel bridge over water in Amsterdam

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5 / 5 (1) Jun 19, 2015
Like the printing press this technology could one day evolve to be.
3 / 5 (2) Jun 19, 2015
That picture however, is a CGI rendering. I was dissapointed.
This technology as it is would only work on bridges that span a couple meters, because the two halves have to be self-supporting until they meet. Beyond that, you need to build a scaffolding first, and eventually you need to build a suspension bridge, and the gradual additive method stops working.

The other point is, that making bridges this way is hundreds of times slower and uses up more energy, because it takes more processing to make the wire for the MIG welders than it takes to roll steel into standard size struts that are simply cut to lenght and then welded or riveted at the ends.

You also need to supply the shielding gas to prevent slag and rust, and it's something like argon, which doesn't come cheap. A gas like nitrogen wouldn't work because it makes the weld brittle, and high concentrations of CO2 causes sputtering.
3 / 5 (2) Jun 19, 2015
It actually brings up another point on 3D printing in general.

In order to make a 3D printed part, you first need to make steel, which comes in huge multi-ton slabs out of the smelter, which are then rolled and cut into smaller billets, etc. etc. until you finally have to grind it into powder for the 3D printer. The forming and grinding process is a huge energy expense, and then you re-melt the steel with a laser which again costs you energy and time.

It seems to me, intuitively, that hammering or rolling the steel billets roughly into shape at the first steps of the process while it's still hot from the smelting, and then simply removing excess material by traditional machining, is a much cheaper process in every sense.

You can saw or blowtorch off a chunk of steel from a billet or a slab much cheaper than you can print the same volume of steel by melting particles together.
3 / 5 (2) Jun 19, 2015
3D printer technology is about 20 years old and was used in the industry for years but in very limited engineering applications due to cost and very narrow applicability mainly because its inability for extreme load bearing.The current hype is just desperation of the investors that want to find popular application for 3D print to recoup their investments and split. But such applications, barring few gadgets, are none.
3 / 5 (2) Jun 20, 2015
That picture however, is a CGI rendering. I was dissapointed.
...CO2 causes sputtering.

Indeed, it has not yet been decided which model will be built of a series of proposals and they are also still deciding were the bridge will be placed. The only thing known is that it will be placed above one of the grachten (channels) in the centrum of Amsterdam.

The whole thing is more a proof of concept and PR stunt for 3D printing as the whole process will be visible to the public.

CO2??? That doesn't exist, you heretic!!
3 / 5 (4) Jun 20, 2015
It seems to me, intuitively, that hammering or rolling the steel billets roughly into shape at the first steps of the process while it's still hot from the smelting, and then simply removing excess material by traditional machining, is a much cheaper process in every sense
Consider construction in space. Bulk powder is lifted into orbit and massive complex structures are printed monolithically without having to sort and join various different shapes which are subject to tolerance errors during manufacture.

This makes the rapid production of vehicles and habitats possible, and can be done completely by robots.

Of course the same is true on earth. Fabricating, delivering, sorting, staging, hoisting into place, and connecting are all expensive and time-consuming and prone to error and inadequate field-mods. Monolithic printing avoids a lot of this.
2.3 / 5 (3) Jun 20, 2015
his technology as it is would only work on bridges that span a couple meters, because the two halves have to be self-supporting until they meet. Beyond that, you need to build a scaffolding first
You guessing again Eikka? Bridges are often built exactly as shown, with self-supporting parts extended until they join.
3 / 5 (4) Jun 20, 2015
have to grind the powder
Yes sadly, you are guessing again.

"Atomization is the process used commercially to produce the largest tonnage of metal powders. In water and gas atomization (Figures 2-1 and 2-2, respectively) the raw material is melted then the liquid metal is broken into individual particles. To accomplish this, the melt stock, in the form of elemental, multi-element metallic alloys, and/or high quality scrap, is melted in an induction, arc, or other type of furnace. After the bath is molten and homogenous, it is transferred to a tundish which is a reservoir used to supply a constant, controlled flow of metal into the atomizing chamber. As the metal stream exits the tundish, it is struck by a high velocity stream of the atomizing medium (water, air, or an inert gas). The molten metal stream is disintegrated into fine droplets which solidify during their fall through the atomizing tank."

-Knock it off.
2.3 / 5 (3) Jun 20, 2015
Ironic that the article mentions "emperors new clothes" when the only examples are cgi renderings. Thanks Eikka. BTW, the bridge proposed is built from one side to the other, not in halves. The lower structure is strong enough that the weight of the robots isn't enough to collapse it during the construction.

Lex Talonis has some interesting comments about the costs at the link below.

A two month build time for a small bridge is not exactly rapid production. See link.
Bridge building is so easy and standardized that 3d printing one is really an exercise in publicity than engineering. Hype by a more polite name.

I find it amusing the amount of publicity every small advancement in additive technology receives. It has always been an evolutionary rather than a revolutionary process.

I can imagine my grandfather saying "why that's just cnc weldin' rod art" and shaking his head.
5 / 5 (1) Jun 21, 2015
Patents will slow this takes 20 years for every new patent to expire and then those technologies become actually meaningful to the large scale population..

many patents shouldn't be issued too...these patents give 100% ownership to people who can't possibly be 100% responsible for the "invention"
5 / 5 (1) Jun 22, 2015
You guessing again Eikka? Bridges are often built exactly as shown, with self-supporting parts extended until they join.

You might notice that that is a beam bridge made out of pre-made elemets, which are lifted in place with cranes.

It's the same cranes that keep the bridge from tumbling down before they're connected. The bridge is not self-supporting until it is finished. Of course, you could support a 3D printed bridge with cranes as it's being made, but since any larger bridge would take years to print, wind, temperature changes (expansion) and seasons become a problem in the large scale.

Those elements are also internally pre-tensioned, and lashed together with more cabling after being put together, before the cranes are removed. A 3D printer can't do that, nor can it work-harden metal.

Breaking the bridge up into elements and manufacturing the elements in parallel is much faster anyways
3.7 / 5 (3) Jun 22, 2015
The other thing is, when you grow a metal rod by welding, it's in a similiar state as a piece of newly cast metal - soft. When you put stress on it, it starts to stretch, bend or compress, until the crystal structure of the metal starts to work-harden and becomes stiff.

It's like a guitar string which won't keep tune until you've re-tightened it several times. The first time you strain it, it won't return to its original length, so when you play the string it goes slack, and you have to re-tighten. Same thing happens to bridges.

That was the problem with cast iron. The parts had to be made much stronger and larger than necessary to prevent sagging. Wrought iron on the other hand was hammered and rolled into shape and the parts could be made lighter because it was already work-hardened by the hammering. Steel works the same problems out by heat-treatments.

The 3D printer bridge is in a similiar predicament as the cast-iron bridge, depending on how the weld cools down.
not rated yet Jun 22, 2015
Consider construction in space

Or just in any other environment that were humans could not (or it would be to expensive to) operate, such as under water, inside of reactors, tanks with fluids / gases.

And once we could optimize the process we could just 3D print small bridges and structures from recycled plastic that could be temporarily placed for (say) the Gay Pride or Sail to accommodate more people or just while other pedestrian / bicycle bridges are repaired.

We are not necessarily talking about 3D printing the Afsluitdijk ... but who knows ;)
not rated yet Aug 14, 2015
'Here I am, the most intelligent robot in the galaxy, welding a bridge.'

The only galaxy in which that 3D printer would be the most intelligent robot, is a Ford Galaxy.

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