# 3d Print Bridge Steel Bridge In Amsterdam



## CluelessNewB (Jun 15, 2015)

This looks like an interesting project.


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## RJSakowski (Jun 15, 2015)

Fascinating!  Them robots be cool critters! I had never seen additive machining done in this fashion before.


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## hermetic (Jun 15, 2015)

Just tell me again how long that took to make, and how much all that machinery cost! In case no one noticed, we have been building bridges from either bank for quite some time, and have got very good at doing it without robots, and without pretending a mig welder is a 3d printer. Desperately looking for something new or clever here!


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## RJSakowski (Jun 15, 2015)

The new or clever here is the ability to fabricate complex structures in steel through an additive process.  Fifteen years ago 3D printing was a toy.   Now manufacturing is rapidly adopting additive processes as a viable alternative to conventional machining and the processes have been improving tremendously.  One of the benefits has been the ability to create structures with complex internal geometry which previously have been difficult or impossible to accomplish.  It will never completely replace conventional machining as a solution but it is another tool in the tool box.

As for the robots, virtually  every modern machine shop has robots working for them in the form of CNC machining centers, lathes, and metal forming.  I don't think that anyone can deny that they have greatly enhanced the capability of those shops.

I don't believe for a second that the Amsterdam people were trying to say that you can build a bridge by this process; they were just using the bridge as demonstration of a process.  Much in the fashion the Abraham Darby did in Shropshire in 1779.


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## hermetic (Jun 15, 2015)

+"The new or clever here is the ability to fabricate complex structures in steel through an additive process."
We have been making complex structures in steel since the victorian times, unless the 3d process is cheaper, faster, or stronger it has no advantages(and many disadvantages) over the ways we already know. 3d printing does have it's uses, such, as you say, stuctures with complex internal geometry, and it has been used to create the "scaffolds" and then print cells for making replacement organs for transplant. This is a field where we have no other technology to do the job. Bridge building has been covered by many different technologies, all of them faster, cheaper and stronger. People who have investment in this technology are trying to convince the world that you can make anything with 3d printing, and essentially, you can, provided you are not worried about how much it costs, how long it takes, and if it is any use when it is finished. In short, like Graphene, and nanotechnology, it is not going to revolutionise anything, although those with investment in this technology will try to convince the world that it will


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## David S (Jun 15, 2015)

3D printing has lots of advantages.  First and more most it is additive and therefore there is very little waste, except for the foundation material depending on the process.

We had 5 3D printers to make prototypes from polymeric materials that other wise would have to be made by soft tooling plastic injection moulds.  Or cnc machine for solids.  We could even produce prototype lawnmower decks to verify cutting efficiency, air flow, bagging discharge etc.  Depending on size we could make one in a couple of days.  The machines could run on their own 24/7.

This technology is constantly involving.

David


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## RJSakowski (Jun 15, 2015)

Manufacturers use a process because it provides better or less expensive or faster turn-around-time products.  They are not prone to adopting a process just because it is cool.  

An additive manufacturing job shop a few miles away has been making parts for a major Wisconsin motorcycle manufacturer for more than five years.  For low run volumes it is often more cost effective than machining molds for injection molding.  While working for a Fortune 500 company, we used additive manufacturing to verify design prior to investing in molds for high volume production.  Current technology is producing functional metal parts using a laser fusion additive process.

While the process is typically longer than more conventional manufacturing, the parts made can, in many instances, be made tens or hundreds at a time. The ability to make internal structure permits parts to be made as a single entity rather than an assembly, eliminating assembly time and labor and fasteners.


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## hermetic (Jun 16, 2015)

Read my posts again, I didn't say it didn't have it's uses, I just said that bridge building Isn't one of them. All the examples above are saying exactly what I have said, there are certain niche areas of manufactuing where 3d printing has advantages over other methods, and this is where it should be used. To say that 3d printing is going to revolutionise everything is just hype, and combining a mig welder and a robot arm is not clever, revolutionary or innovative. You only have to consider the cost of the wire and the gas used to realise that this would be a ludicrously expensive and slow way of making a 2 foot bridge. As to the "concept" most people in engineering have been using welders as 3D printers to build up worn components for as long as welders have existed, google "metal spraying" and you will see applications of "additive processes" that were in use decades ago. If you happen to want a small number of items that happen to be made of plastic, then the cost of diemaking for injection moulding is prohibitive, if you wanted a large number however, once the dies are made, the cost per item produced is tiny, and the speed with which they are made is incredible. Large companies may be using the technology, but look at the cost of the machinery they are using, and the investment has to be recouped from making components. CNC machining centres make components very fast, even the most expensive and advanced 3D printer is slow by comparison, and when you compare with injection moulding, positively static!  As far as home 3D printing use is concerned, I saw a post on one of the sites (may even have been this one!) saying "anyone know whats going on with 3D printing, all the sites have gone very quiet"
Phil


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## Tony Wells (Jun 19, 2015)

I guess in space dock, we won't need shielding gas when we frame out the NCC 1701


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## Grumpy Gator (Jun 19, 2015)

Beam me up Scotty.
Second star to the right and straight on till morning.
                   ***G***


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## RJSakowski (Jun 19, 2015)

OK Phil, Uncle!  You obviously have very strong opinions about this.  

My point is that the process is simply another tool in the toolbox.  The decision to use a particular tool should always be on the basis of it being the best choice for the task.  And while it is highly unlikely that a mig robot will be building a bridge over the Thames or the Potomac, I could see a definite advantage in a robot building a structure in space.

As to the viability of additive manufacturing, the company I mentioned earlier is growing in excess of 50%/yr.


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## hermetic (Jun 20, 2015)

I don't really like opinions, they are like figernails, you grow them, then cut them off and grow some more. I try to base what I say on fact rather than opinion. Lets go a bit deeper, what is the basic problem with 3d printing/additive construction.? The answer is getting the new layer you have just printed to bond perfectly to the layer below it. This is the major flaw with plastic 3d printing, if the lower layer chills too fast, the next layer does not bond properly, and your component cracks and falls to pieces. So you have to keep it clean, and add more heat, more heat=more energy, and energy is expensive. Dust inclusion is also a problem, and clean rooms are even more expensive! Brittleness is one of the recurring themes you see in 3d plastic printing.
  Now lets look at the "bridge". Using mig technology outside in the open air, is not impossible, but difficult, as any breeze or air movement will blow away the sheilding gas, and the weld will oxidise, so your additive process will consist of layers of steel with layers of oxide between them. At best this will cause corrosion problems, at worst, the structure will shear at the material layer interface.................not good in a bridge! 
Phil


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## RJSakowski (Jun 20, 2015)

The problems you mention seem to be restricted to FDM printing.  I don't know anyone who seriously uses the plastic extrusion process for additive manufacturing.  At least the processes that I have seen are laser activation or laser fusion.  The commercial units operate in environmental chambers so a clean room is not required.  From what I have seen and parts that I have had made, structural integrity is not an issue.


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## nobog (Jun 20, 2015)

So...   "at work"  we are "in a hurry"

1. Engineers are directed to make specific fixtures _*as soon as possible*_
2. This is simple, send the 3D CAD model to building #2
3.  They rapid prototype the parts and send the parts to our lab
4.  I get the parts, determine the parts do not meet tolerances/specs
5.  throw 10's of thousands of $ worth of parts in the garbage
6.  Have the parts machined out of Delrin
7.  they work perfectly
8. - should have been done in the first place

Jim


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## hermetic (Jun 20, 2015)

So how much does a laser fusion 3d printer in an environmental chamber cost as compared to an injection moulding machine , and remember the injection moulding machine will make approximately as many parts in a couple of seconds as the printer will make in a day.


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## John Hasler (Jun 20, 2015)

hermetic said:


> So how much does a laser fusion 3d printer in an environmental chamber cost as compared to an injection moulding machine , and remember the injection moulding machine will make approximately as many parts in a couple of seconds as the printer will make in a day.


What does an injection moulding machine that will produce one part *today* cost?


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## RJSakowski (Jun 20, 2015)

hermetic said:


> So how much does a laser fusion 3d printer in an environmental chamber cost as compared to an injection moulding machine , and remember the injection moulding machine will make approximately as many parts in a couple of seconds as the printer will make in a day.


Actually, depending of course on the features, in the same ballpark for cost.  The laser fusion process is making metal parts however.  In metals like stainless or titanium.  The time I watched the process at work, they were making  about fifty parts in stainless over the course of several hours.

Setup for making injection molded parts requires the manufacturing of often very complicated molds which can run into the 100's of thousands of $.  The process of making a mold for a part that was started three years ago has yet to produce the first good part.  There are severe constraints regarding the design of moldable parts which often can compromise the functionality of the part.  When calculating the cost per part, all of these factors must be considered.  That as opposed to porting a CAD model into the printer.

I don't believe for a second that additive manufacturing is the last word.  I would also be very hesitant about printing a bridge.   Rather, I would consider the all the factors and try to select the best solution for my needs.  Again, I see additive manufacturing as another tool in my toolbox.


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## hermetic (Jun 21, 2015)

and there you have the answer, and we agree, for some things 3d printing is ideal, but it is just another tool in the toolbox, and printing a bridge is pure hype!


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