Additive Alchemy - How 3D Printing Is Reshaping Manufacturing
Michael Chu
Product Management | Product Marketing | Product Development | Program Management | Process Improvement
What Is 3D Printing?
If you have been following my blog series on technology and the industrial sector , you will remember that I mentioned 3D printing, or additive manufacturing, in my previous post, "One Size Does NOT Fit All" - How Technology Is Enabling Bespoke Manufacturing 2.0 .
I promised that I would spend an entire article on additive manufacturing and 3D printing, so here it is!
Traditional manufacturing involves subtractive processes that start with raw material and remove portions to get to the desired part. Subtractive manufacturing is generally faster at scale. However it requires dedicated tooling which adds to overall cost and lead time. This makes it unsuitable for small batches or custom production. It is also potentially wasteful depending on how much material must be removed.
3D printing turns subtractive manufacturing on its head.
Instead of taking material away, we build up the part that we are trying to create from raw materials, like plastics, metals and other material that can be manipulated bit by bit to add to the final object. Since special tooling is not required, the startup costs and time are much less. This makes it especially attractive to manufacturers making more bespoke products.
We are starting to see a lot of interest and growth potential for 3D printing in a variety of markets as the technology improves (more on that below) and costs go down. One study predicts that the global 3D printing market will reach $34.5B USD by the year 2028. Not only that, it is expected to grow at an impressive 18.1% Compound Annual Growth Rate (CAGR) from 2023 to 2028.
Not too bad... and that should definitely pique your interest.
A Brief History
With all of the interest and hype around 3D printing in manufacturing circles, you might assume this is relatively new technology.
Would it surprise you that 3D printing has been around for over 40 years??
The first documented appearance of 3D printing can be traced back to 1981 when Hideo Kodama tried to create a rapid prototyping machine. He used a technology that is known as Stereolithography (SLA). SLA uses a vat of liquid polymer resin that hardens when exposed to ultraviolet (UV) light. The final object is built up layer by layer - more on this and other technologies in section below, "How Do They Do It? The Technology Behind 3D Printing".
Unfortunately for Hideo, his patent application was rejected due to a technicality, missing a filing deadline!
Instead, several years later, in 1986, an American furniture maker, Charles Hull, ended up receiving the first patent for SLA . Charles founded a company, 3D Systems Corporation, around this patent and released the first commercial SLA 3D printer in 1988.
That same year, in 1988, a student at the University of Texas, Carl Deckard, filed a patent for Selective Laser Sintering (SLS) which basically uses a laser to melt powdered material to form the solid structures of the final object. The first commercially available 3D printer using SLS technology was introduced in 2006.
In 1989, Scott Crump filed a patent for yet another 3D printing technology, Fused Deposition Modeling (FDM) , also known as Fused Filament Fabrication (FFF). Instead of relying on the finished piece sitting in powders or liquids waiting to be melted or hardened, FDM heats up plastic filament, much like a hot glue gun, and deposits the material layer by layer. In this way, it is quite similar to ink jet printers, but in 3 dimensions. FDM is currently one of the most widely used 3D printing technology due to its low cost, ease of use and simplicity.
However, what really helped 3D printing take off in popularity was the open source project, the RepRap Project , started in 2005 by Adrian Bowyer. The goal of the project was to rethink 3D printing using a low cost technology, FDM, to create a printer that was capable of replicating the plastic components needed to build an identical 3D printer. The design was provided at no cost to everyone to encourage the proliferation of the design to everyone who wanted it.
The RepRap Project encouraged the creation of several commercial 3D printers, especially since many of the original patents around FDM started to enter the public domain around that same time.
Since then, the price of 3D printers has greatly declined and the quality and ease of printing has improved. This has made them much more accessible to the general public.
The printing technologies have also continued to evolve and now include other materials, such as metals, carbon fiber, glass, etc.
So What? How Is 3D Printing Changing Manufacturing?
As commercial 3D printers have become more readily available, we are seeing their use in a variety of industries, such as aerospace, architecture, manufacturing, automotive, building construction, healthcare and more. We have even seen 3D printing done in space on the International Space Station , paving the way to long-term space expeditions by changing the potential nature of the supply chain (more on that below).
3D printing is certainly revolutionizing the manufacturing industry, making it more efficient, customizable and ushering in previously unimaginable possibilities. Here are just a few of the important influences this technology is already having.
Faster Development Cycles
When developing or refining a new product, there is only so much designers and engineers can do completely in software and simulation. Even with the advances in Computer Aided Design (CAD), there is no substitute for actually creating a real physical prototype to test with potential customers and in the actual environment the product will be used in.
Traditional manufacturing requires the creation of custom tooling and minimum production quantities, increasing the time and cost to create every iteration of a product prototype.
3D printing allows designers to significantly reduce the costs associated with manufacturing a prototype, eliminating tooling costs and allowing them to create a small number of units without penalty or waste.
As 3D printer costs continue to drop, many more companies may decide to purchase an in-house 3D printer, further reducing the time it takes to create a physical prototype by eliminating the shipping time from an outsourced printing company.
Design cycles that used to take weeks to months can now take only hours to days!
Reimagined Supply Chains
In the previous section, we talked about how 3D printing is drastically reducing the time it takes to develop and test a new product. However, 3D printing is also making positive impacts to manufacturing production supply chains.
Traditional manufacturing supply chains assume that the production of products is done in a few central factory locations. A large batch of products is mass produced to amortize the production costs and lead times inherent in traditional scale manufacturing. Then, a network of distributors, warehouses and transportation logistics are needed to get the product to the end customer.
3D printing revolutionizes the manufacturing supply chain by letting companies decentralize production, moving it closer to where the end customer needs the product, leading to lower lead times and logistic costs. Products can also can be produced on-demand, reducing inventory and warehousing costs as well as minimum order quantities.
Decentralizing production also makes the overall supply chain much more robust and resilient. Issues that impact one geography and location, such as natural disasters, no longer need to impact the global availability of a product.
With decentralized production. we can even enable a "supply chain" where it was previously impractical or impossible - for example, in a remote terrestrial location (impractical) or even outer space (impossible) (see the above example of 3D printing being done on the International Space Station)!
Being able to manufacture on-demand can also make products available that would otherwise not make economic sense to produce and inventory.
In some industries, updating equipment may be difficult due to cost or regulations. However, they cannot afford to have long downtimes if an older or obsolete part breaks. In the past, this meant that they would need to pay significantly higher prices to buy and inventory enough spare parts "just in case". With 3D printing, they can order up or even print for themselves the replacement parts they need, when they need them.
The "Impossible" Becomes Possible
The last influence I want to talk about in this article is how 3D printing is making it possible to physically realize some designs that would either be impractical or impossible to create through traditional manufacturing techniques.
These types of designs are often highly complexity or contain structures within other structures that would be difficult to make using subtractive manufacturing. However, when combined with generative AI (see my previous article on generative AI to learn more about this exciting technology), some very cool and exciting products are possible.
I will talk a bit more about generative AI and 3D printing later on in this article.
If you wanted to see a showcase on various "cool parts" made possible with 3D printing, I recommend watching "The Cool Parts Show" .
How Do They Do It? The Technology Behind 3D Printing
All the various ways to 3D print today involve either melting or hardening some type of raw material. Where they differ are in:
Let's take a look at some of the most common methods in use.
Stereolithography (SLA)
One of the earliest 3D printing technologies, SLA was first used by Hideo Kodama and Chris Hull in the early days of 3D printing.
In SLA, you start with a vat of liquid polymer that cures or hardens when exposed to a certain type of light, usually a UV laser. There is a moveable platform mounted on a piston that can move the platform up or down very precisely.
The design is decomposed into thin layers, starting from the bottom and going up to the top. This decomposed design is fed to the 3D printer with the platform starting nearly at the top of the vat of polymer. Some SLA 3D printers will do this upside down, pulling the platform slowly up and out of the vat as the next layer is hardened onto the partially completed structure.
This method is known to be able to print a high level of detail because of the fine resolution of the laser. After the 3D printing is done, the piece is carefully removed from the platform and technicians may refine the surface or perform some final steps to ensure a robust curing of the material.
领英推荐
Here is a time lapse video of a piece being printed with SLA. You will see that this 3D printer pulls the finished product out of the vat instead of lowering the platform.
Selective Laser Sintering (SLS)
SLS, similar to SLA, also uses a laser to create the details of the design. However, unlike SLA which uses the laser to cure and harden liquid resin, SLS uses a powerful laser to melt some kind of powdered material to get it to stick together.
A roller spreads a thin uniform layer of powdered material and then a laser is passed over the new layer to selectively form the next later of detail. Then, the platform lowered just a tiny bit, the roller spreads out new powdered material and the process repeats until the entire piece is completed.
Spread, melt, lower, repeat...
In addition to being able to form a great deal of detail due to the laser, SLS has an advantage over SLA in that it can work with a wider range of materials. Anything that can be made into a powder and melted with a laser can theoretically be used, including metal. However, metal powder normally melted using Selective Laser Melting which we will discuss in a little bit.
If you want to see the "spread, melt, lower, repeat" cycle in action for SLS, check out this video.
Fused Deposition Modeling (FDM) / Fused Filament Fabrication (FFF)
With both SLA and SLS, the 3D printer required a vat or tub of liquid or polymer. This added to the cost, complexity and processing needed. While some Do-It-Yourselfers (DIYers) purchased these types of printers to 3D print at home, those technologies were still not really accessible for the masses.
With the invention of FDM, the practicality of having a 3D printer at home improved dramatically. If you are familiar with inkjet printers and hot glue guns, you can understand how FDM printers work.
Instead of a vat or tub of liquid or powder, the raw material for FDM printers come in spools of thin meltable plastic filament. The printer has a heated nozzle that is able to heat up the filament so that it becomes soft. Then, like an inkjet printer, the nozzle is moved across the horizontal plane of a platform and deposits the next layer of material for the piece.
Once the printer finishes depositing material for a given layer of the piece, the platform is moved slightly lower, or the nozzle assembly is moved higher. The process then repeats until the entire piece is completed.
The biggest advantage of FDM is the low cost, simplicity and ease of use of this technology over SLA and SLS. It has helped make budget 3D printing available to more enthusiasts.
Watch this time lapse of an FDM printer in action to see just how different the process is.
Digital Light Processing (DLP) / Liquid-Crystal Display (LCD)
You can think about DLP and LCD 3D printing as using the same concept as SLA, curing liquid polymer with UV light. but you are curing an entire layer of an object all at once.
SLA is to DLP/LCD as 1D is to 2D.
DLP and LCD technologies are quite similar when compared to SLA. The main difference is that the UV light in a DLP 3D printer is selectively directed by thousands of tiny mirrors whereas the UV light in an LCD 3D printer is filtered through an LCD screen.
Both have the obvious advantage in terms of speed but you sacrifice a little bit in terms of resolution when compared to SLA.
A good tutorial on the differences between SLA, DLP and LCD 3D printing can be seen here .
Selective Laser Melting (SLM) / Direct Metal Laser Sintering (DMLS)
SLM and DMLS are similar to SLS technology in that they all use a high-power laser to melt the raw powdered material to form the object.
The main difference is that SLM and DMLS melt metal powder instead of polymers.
When melting metal powder, some additional care must be taken when designing the 3D printer. First, the build chamber is normally filled with inert gases like argon or nitrogen to help with the melting. Also, SLM and DMLS usually use higher temperatures to melt the metal powder meaning sufficient cooling of the finished part must be done before handling.
Electron Beam Melting (EBM)
EBM is similar to SLM and DMLS in that it melts metal powder to build an object.
However, instead of a high-power laser, EBM uses an electron beam to melt and fuse metal powders.
Even more care needs to be taken with EBM due to the amount of higher energy source being used, such as working in vacuum and being even more careful about handling a very hot finished object.
EBM allows you to use heavier metal powders which are safer for workers to be around than the fine powders used in SLM and DMLS.
EBM 3D printed objects tend to be more robust and stable with less warping. This stability makes it more appropriate than SLM and DMLS in industries such as aerospace and medical devices.
A good explanation of EBM can be found here .
Binder Jetting
The final 3D printing technology we will talk about is binder jetting. Unlike all of the previous methods discussed in this article, binder jetting does not involve melting or curing. Instead, a liquid binding agent is repeatedly deposited onto successive layers of powdered material to glue together the material into the final object.
Since no heat is used in the building process, binder jetting can be used with build material that may be sensitive to large changes in temperature.
In some cases, such as with bounded metal powder, after the object is 3D printed, also known as a green part, it will be heated, or sintered, to provide more strength to the object by bonding the individual particles together as a solid. In this case, the binding agent is used to give the powder enough structure before being finished.
Also, since the green part is surrounded by loose, unused powder, no support structures are needed during the printing process. Binder jetting is often less expensive since it does not need more expensive lasers or electron beams, especially when working with metal powders.
A great explanation of the various uses of binder jetting can be found in this video .
Unleashing The Potential Of Generative AI With 3D Printing
In my previous blog, "Generative AI and Industry 4.0 - It's Already Here... Are You Ready?" , I talk about how generative AI is being used to help jumpstart the design process by giving engineers a functional framework to start with so that they can focus most of their time on modifying and validating that design for their unique situation. This jumpstart is applicable no matter if you intend to use traditional manufacturing techniques or 3D printing.
The really interesting potential of generative AI for product design is when we allow it the freedom to go beyond traditional manufacturing constraints and present novel and unconventional design structures that a human designer might not even think about. The catch is that some of the design structures that a generative AI algorithm might come up with may be very difficult or wasteful to try to manufacturing with normal techniques.
Also, often design engineers employ generative AI because existing off-the-shelf products are not able to meet their needs within the operating constraints, such as size, volume, weight, ... This means that once they finalize their design, they may not be able to take advantage of the economies of scale since they may only need to build a few, or even one.
An extreme example of a generative AI and 3D printing with constraints both in design complexity, uniqueness and scale (often only one!) is the work by NASA's Goddard Space Flight Center on what they have called "evolved structures" .
With "evolved structures", NASA is able to create structures that may look weird and alien, but weigh less and can handle much higher structural loads than parts designed by humans. Also, NASA is often producing thousands of bespoke parts but only one or two of each design, making traditional manufacturing techniques cost-prohibitive.
On the opposite end of the spectrum, generative AI and 3D printing allowed the Wilson Labs team at Wilson Sporting Goods Co. to design and produce an airless basketball ! Take a look at this video to see how they made it.
The Future Of Manufacturing Will Not Be The Same
Even with all of the advances in 3D printing, traditional scale manufacturing is, at least for the near future, not going to disappear. However, as we have seen in this article, the technology in 3D printing is advancing quickly, making it more cost-effective, easier to use and overall more accessible. When paired with generative AI, I don't think the manufacturing industry has yet to see the full potential and impact of 3D printing.
Do you see yourself using 3D printing? How do you think it will impact your business?
Share your thoughts and experience.
Credits/Acknowledgements:
I have 8 3D printers, and at any given time at least 2 of them are earning their keep. I can't understand how an inventor or designer could live without them. Soon the CAD tools will catch up, instead of slowly migrating from 2D legacy tools with 100s of features that require memorization. There are online tools that are getting close, but asking you to donate your IP to their library so they can learn how things are done. You either work on the future or you become history.