ABSTRACT: Since 2005, three-dimensional(3D) printing has experienced rapid advancements in functionality due to the open-source community, but in recent years mainstream manufacturing has invested time and money to advance 3D printing faster. With this interest from mainstream manufacturing, 3D printing has become cheaper, faster, and more applicable for large-scale applications. Based on this rapid growth, I argue that 3D printing can entirely restructure the supply chain, thereby benefiting the end user. With the growth of 3D printing, understanding the advantages and disadvantages that come with 3D printing will allow companies to better use the technology in manufacturing. I have conducted my research over multiple research papers written by Ph.D.s' and workers of RAND Corporation. With these credible sources, I will discuss the different types of additive manufacturing, the effects on the supply chain, the environmental impact, and how additive manufacturing can be simplified for household use. I will prove why additive manufacturing, more specifically Fused Deposition Modeling printers, is viable for household use and how 3D printing will change the functions of the supply chain, per the aforementioned research foci. Ultimately, 3D printing will result in cheaper parts, decreased wait time, and incensed accessibility without negatively impacting the environment.

The Future of Additive Manufacturing

    As the population of the earth increases, more products are required for those people. With this dilemma, it is necessary to find a more cost-effective way to produce those products and also reduce carbon emissions to protect the earth. Additive Manufacturing(AM) can help achieve this future. AM is a cheaper, faster, and more environmentally friendly option than Subtractive Manufacturing(SM). AM also introduces new ways to restructure the supply chain, bridging more cuts in cost and carbon emissions. Due to AM’s promising future, many advancements have been achieved within only forty years.  This rapid growth in additive manufacturing introduces new ways to reduce the supply chain, enabling benefits in cost, time, and environmental impact; these benefits prove that additive manufacturing is the future that businesses need to prepare for.

Since AM is very different from SM, they have different advantages and disadvantages even though they achieve the same end result. According to Simon Véronneau, a Ph.D. in Operation Management from the NPS Graduate School of Defense Management, SM uses a solid block for starting material and shaves off material that is not the end product. This is achieved by cutting, drilling, milling, and lathing, resulting in the end product. This method is not material-friendly since most of the start material is shaved off and unusable (5). AM starts with nothing on the build plate and adds only material where it is needed for the end product (besides support material needed for some methods of AM). This makes AM less wasteful than SM. The advantage of SM is that manufacturing is already using this method, along with SM having better mechanical properties than most AM methods. AM enables more complex geometries and creates less waste but can also result in a rough surface finish. Both methods have great capabilities but there are also methods using a hybrid of AM and SM. The product is produced with AM methods but is slightly oversized, then using SM the part is brought to final size. This allows both methods’ advantages without dimensional inaccuracy (Véronneau 5).

    Since SM and AM are broad terms to describe many different machines, AM has many different methods. Based on an article written by workers at Protolabs(a manufacturing facility that uses AM), there are two main categories, polymer and metal 3D printing, which have multiple different methods and materials for accomplishing different tasks. Polymer 3D printing has five main categories: Stereolithography(SLA), Selective Laser Sintering(SLS), Digital Light Processing(DLP), Multi Jet Fusion(MJF), and Fused Deposition Modeling(FDM). 

SLA printers stack layers of UV resin on top of each other by curing the UV resin with a UV laser. This method achieves smooth finishes and high, repeatable detail. SLA is best used for test parts due to its accuracy, but it is also durable enough for low-impact uses. The disadvantage of SLA is the large mess, making this method tedious and mainly for more experienced users (Ahart para. 7). SLS printers melt a nylon-based powder layer by layer to form a 3D object. Since the parts are made of real thermal plastics, they are durable and capable of testing how parts fit. With this printing method, supports are not needed because the unmelted material supports the part. The problem with this method is the unmelted powder around the part is hard to clean up and the parts have a rough finish (para. 8). 

DLP printers use a similar method to SLA printers. The only difference is DLP uses a screen across the whole build plate instead of a laser. This means the printer produces each layer in the same amount of time. This enables faster printing, making it “much more suitable for low-volume production of plastic parts” (Ahart para. 9). DLP has the same disadvantages as SLA. Similarly to SLS, MJF builds parts out of nylon powder. The difference is that “Rather than using a laser to sinter the powder, MJF uses an inkjet array to apply fusing agents to the bed of nylon powder. Then a heating element passes over the bed to fuse each layer” (para. 10). This results in a better surface finish along with more consistent mechanical properties. Just like SLS, MJF does not need support, and is still challenging to clean (para. 10). FDM is the most common desktop 3D printing technology. FDM printers use an extruder to melt a thermoplastic and push it through a nozzle layer by layer. It is cost-effective and quick for creating physical objects since it has minimal cleanup after the print. This method enables multi-material printing, allowing different material properties in one part. The limits of FDM are the rough surface finishes, dimensional inaccuracy, and lack of strength (para. 11).

There are only two methods for metal 3D printing: Direct Metal Laser Sintering(DMLS) and Electron Beam Melting (EBM). DMLS uses a laser to stack melted layers of powdered metal. This method allows for strong yet lightweight parts. Since this only melts the metal that is part of the end product, it is cheaper and faster than traditional milling. DMLS also allows for “multi-part assemblies into a single component or lightweight parts with internal channels or hollowed-out features” (Ahart para.12). Due to the use of traditional metals “DMLS is viable for both prototyping and production” (para. 12). The weakness of this technology is rough finishes and difficulty cleaning finished parts. EBM is similar to DMLS but it “uses an electron beam that's controlled by electromagnetic coils to melt the metal powder. The printing bed is heated up and in vacuum conditions during the build” (para. 13). DMLS is a more affordable and easier method for metal printing making EBM irrelevant for most use cases unless higher accuracy is needed.

While there are now many forms of AM, it all started in the 1980s but it only gained traction in the mid-2000s. The first patents were submitted “in Japan, France, and the United States in 1984” (Véronneau 6). AM is most commonly known for plastics but “Manufacturers have experimented with using different materials to produce physical objects, including polymers, metals, ceramics, and, most recently, glass” (6). Due to the relatively broad definition of AM, many different methods have been invented in order to improve AM as a whole. One of the most common methods, MDF, was popularized in 2005. This was because of the open-source community dedicating their time to building and improving FDM printers. Since many people greatly invested in this process, the design of FDM printers quickly developed. This resulted in better prints, cheaper parts, and more reliable parts. As FDM printers began being produced by larger companies the advancements accelerated. This made printers even cheaper. As companies searched for better-quality prints, SLA and DLP printers became available to the public. This was greatly accepted since SLA and DLP printers require parts that are next to impossible to produce at home while also providing much higher quality (Véronneau 6).

As AM continues to advance new possibilities become available. With AM becoming more capable it will enable many ways to reduce the environmental impact of production. This can be most effective if AM is implemented in households and factories. According to Peter Nowak, a writer for Corporate Knights Inc., “If it does indeed lead to manufacturing repatriation, the environmental savings on shipping goods across long distances will likely be huge” (2). With the reduction in shipping goods around the world, large amounts of carbon emissions from semi trucks and plains would no longer be a necessity for many products. In addition, Trevor Johnston, a worker at RAND corporation, mentions, “Currently, the self-replicating capabilities of these printers remain limited, and demand is low. However, the implications of such a capability should not be underestimated, especially because some of the current technological challenges are already being addressed” (7). With self-duplication, printers could easily be fixed if a printable part breaks. This would reduce the amount of shipping replacement parts when a printer breaks.

Another advantage of AM for environmental impact is how “Additive manufacturing, where an object is created by adding material to it rather than by machining excess away as in traditional manufacturing, also produces much less waste by its very nature” (Nowak 2). This also brings cost reduction but more importantly, it reduces the amount of energy and carbon emissions that are required to mine precious metals. Reduced waste also helps reduce wasted plastic that is either expensive to properly dispose of or ends up polluting the earth.

This waste can be reduced even more by implementing ways to recycle the small amount of waste products from AM manufacturing. Felix Preston, who has an MSc in Environmental Technology from Imperial College London and a BSc in Geography and Environmental Science from the University of Sussex, says;

The bottom line is that there is no guarantee that 3D printing will deliver sustainability benefits unless we take policy development seriously. We urgently need a green strategy for 3D printing that promotes recyclability, biodegradability, 'regrind' (using old printed materials in new prints) and non-toxic, sustainably sourced materials-building blocks for an integrated, sustainable printing system.

With this implemented in recycling facilities, it would greatly decrease the wasted material if 3D printing was in everyone's home. This could also be accomplished by small-scale recyclers that are currently available but are still expensive.

In order to take full advantage of AM’s environmental impact, implantation in factories and households are vital. This can be achieved fairly simply in factories since DMLS is already an effective way of making metal parts, and for plastic parts, DLP is the most viable since it can achieve high details. But both still require large amounts of clean up making them time-consuming to produce. This means that even though these technologies are replacing some production, it is unlikely for them to lead production in factories for now. This is similar to household use. Out of all methods of AM, the two most functional methods are DLP and FDM, for household use. The problem is DLP is dangerous to clean due to harsh chemicals, making it not optimal for most people, and FDM has rough finishes and terrible overhangs. The biggest problem of both is the know-how required for both. Since these are newer technologies it requires knowing how to repair and troubleshoot when parts inevitably break.

This may make it seem like AM is doomed to only be for makers and prototyping but there are many technologies that people believed would not become accessible to everyone. One example of this is 2D printing;

Originating in the 15th century with Johannes Gutenberg's movable type printing press, 2D printing was long limited to small, specialized shops that required skilled labor to achieve a very small throughput. Several centuries later, rotary printing presses revolutionized the printing field by enabling mass production at a few specialized sites. A full century later, in the 1980s and 1990s, neighborhood print shops started offering printing, copying, and scanning services, making the technology available to the general public at relatively low cost. Finally, home printers and scanners became ubiquitous in the 1990s and 2000s, completely eliminating the barriers to 2D printing technology and leaving neighborhood print centers to refocus on specialized printing services and other value-added activities, such as professional printing posters, oversized prints, and providing integrated document distribution. (Véronneau 9)

The advancement of 2D printing took about 5 centuries to become available to every house. This proves how 3D printing still has time to advance and revolutionize manufacturing and with how many people invested in AM technology it is unlikely that it will take anywhere near this long to do so.

Based on this research, FDM is the most viable option for household use and DMLS is the most functional for factories. Even though both of these technologies are not perfected yet, it is safe to say that within the next twenty years both methods will have revolutionary breakthroughs that will restructure the supply chain. AM will also enable a large reduction in carbon emissions and waste materials. All of these benefits in cost, time, and environmental impact, will allow for a greater and safer future for many generations to come.

Works Cited

Ahart, Matt. “Types of 3D Printing Technology Explained.” Protolabs, 3 June 2019, protolabs.com/resources/blog/types-of-3d-printing/. Accessed 29 Nov. 2022.

JOHNSTON, TREVOR, et al. ADDITIVE MANUFACTURING IN 2040: Powerful Enabler Disruptive Threat. RAND Corporation, 2018. JSTOR, jstor.org/stable/resrep19917. Accessed 10 Nov. 2022.

NOWAK, PETER. “The Promise and Peril of 3D Printing.” Corporate Knights, vol. 12, no. 2, 2013, pp. 16–17. JSTOR, jstor.org/stable/43242759. Accessed 10 Nov. 2022.

Preston, Felix. “Printing with a Greener Ink.” The World Today, vol. 69, no. 5, 2013, pp. 18–18. JSTOR, jstor.org/stable/43857577. Accessed 10 Nov. 2022.

Véronneau, Simon, et al. 3D Printing: Downstream Production Transforming the Supply Chain. RAND Corporation, 2017. JSTOR, jstor.org/stable/resrep17635. Accessed 29 Nov. 2022.