3D Printing: Evolution Rather than Revolution – Part One

An assessment of the current state of 3D printing.

Ralf Steck | Engineering Spot

There’s been plenty of speculation in recent years on whether 3D printing spells the end of the global supply chain.

Given all that talk, it’s time for a clear-eyed evaluation of the effects of this technology on our world. In this two-part series, I’ll focus first on defining the current state of 3D printing. Part two (coming Friday) will take a look at the future of 3D printing.

Is 3D printing truly a revolution?

Answering the question above is not easy because terms like 3D printing, additive manufacturing and rapid prototyping are often used interchangeably, even though they describe different technologies, philosophies and concepts.

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3D printing is becoming an established, market-changing technology.

Today the sophistication and market penetration of these technologies strongly depend on the way they are applied and the industry in which they are applied. However, one thing is certain: 3D printing is becoming an established, market-changing technology in more and more areas.

Recent 3D printing hype may have left the impression that a new technology was taking over the market.

This might have encouraged unrealistic expectations: for example, the impression that within a few months all manufacturing technologies would be replaced by 3D printing and everybody would simply print their spare parts at home.

The beginnings of additive technologies (in contrast to subtractive manufacturing, which uses lathes or milling machines to create shapes by removing material) are older than commonly known.

It all goes back to the beginnings of the two biggest providers: Chuck Hall invented Stereolithography in 1983 and founded 3D Systems, and in 1989, Stratasys founder, S. Scott Crump, patented Fused Deposition Modeling, which is used in almost all affordable 3D printers today.

This represents almost 30 years of development and industrial practice, in which a large variety of additional technologies emerged, each of which fulfilled special requirements.

It’s correct, however, that the market exploded after the expiration of the most important patents, which accelerated developments. In the field of materials, great improvements can be observed from year to year, and real-world applications are steadily increasing.

The focus actually has shifted from rapid prototyping toward rapid manufacturing and is gaining influence within the supply chain sector.

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However, what was mere speculation back then can now be analyzed using real-life examples. If one takes the available technologies and their abilities into consideration, it’s possible to more accurately decipher where things are heading.

Fact 1: Printed parts are dependent on the stress direction.

The materials used in 3D printing (usually) do not behave realistically. This sounds strange at first if you know about the increasing variety of plastics for 3D printing and recognize that metals like titan, stainless steel or gold are already processed.

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3D-printed components are always constructed in layers.

Yet, when it comes to plastics, a 3D-printed part always behaves differently from an injection-molded part. Since laser-printed parts from metal do not depend on stress direction as much, the aforementioned only loosely applies to them.

3D-printed components are always constructed in layers. This leads to anisotropic material properties, especially with plastics, which means the properties depend on the stress direction, quite similar to wood. The plastic molecule chains always lie in layers, and if at all, they just barely conjoin with the chains of the underlying layer.

So the same material will behave differently depending on whether it was injection-molded or printed. During the laser-printing process of metal, tiny grains of metal are fused together, which leads to a strong adhesion between the layers, and thus, increased homogeneity.

It should be taken into account that a higher material thickness makes up for the reduced strength. This means, however, that when fulfilling the same requirements, a 3D-printed part will look different from an injection-molded part or a part milled from a block of metal.

Fact 2: Production times are long.

The layered manufacturing process must also be taken into account. The finer the surface and the more detailed the part, the thinner the individual layers – 0.2 millimeter-thick layers are rather coarse, and fine surfaces would require layers less than 0.1 millimeters thick. Consequently, the components need a longer processing time.

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The major advantage of 3D printing is the great freedom of design.

And since the entire surface, or at least the outer contour of the geometry in every layer has to be processed, time spent for production strongly increases with the size of the component. That is why there are few large printers.

When using 3D printing, it is quite common for production to take hours, or even days, while in injection molding, sometimes dozens of parts can be manufactured per minute. Therefore, 3D printing is not suitable for mass production – yet.

Fact 3: Complexity is free of charge.

The major advantage of 3D printing is the great freedom of design. This procedure allows for manufacturing virtually any shape, even multi-part, movable assemblies.

When it comes to conventional manufacturing processes such as milling, the more complex the shape of a part, the greater the expenditures. This is due to the necessity of using various milling machines or clamping the part several times.

With a 3D printer, it’s of little importance whether it prints a cube or a ball – only the printing time slightly increases.

If those parts were injection molded, they wouldn’t need extensive post-processing, as their complex geometry keeps them in the mold. In this case, it might be cheaper to 3D print these mass production parts.

Taking these three aspects into account helps us understand where 3D printing will have the largest impact. It also sheds some light on where advancements are needed. goldbrown2

Check out part two in this series Friday, which explores four applications of 3D printing and what they mean for the future of the industry.

This article first appeared on All Things Supply Chain and was published with permission. 

You might also like:

Seeing Logistics in 3D

7 Ways 3D Printing Is Disrupting Global Manufacturing

How Tech Firms are Driving the 3D Printing Revolution

Ralf Steck is a mechanical engineer, specialized freelance journalist, author, moderator and speaker. He blogs at http://www.EngineeringSpot.de about software and hardware for digital product development.

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2 Comments

  1. shabnumofficial

    Traditional manufacturing will always be there, Mostly 3D printing service is employed for rapid prototyping and short-run manufacturing. 3D printing certainly has its lot of extraordinary benefits, with it we can design anything and now with almost any material, which was not possible earlier. Time is changing but i believe traditional manufacturing will all be there for bulk production.

    Regards,
    https://www.customprototypes.ca/3d-printing

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