The Additive Manufacturing Frontier

This paper will share a basic understanding of the “Big 3” methods of additive manufacturing and then discuss why the industry is ripe for explosion and investment. Additive manufacturing (aka 3D Printing) is still a relatively new technology in the grand scheme of things and, in my opinion as well as the opinion of many others, still has a ways to go before being realized for its potential.

One of these others is an individual whose works I study almost religiously and who I believe to hold an accurate vision of this technology’s potential: Dartmouth professor Richard D’Aveni. I’ve cited his work previously in my article on AMPEL, and his book “The Pan-Industrial Revolution” is an excellent roadmap for the future of the industry. Recently, he and an associate published another, shorter piece about the big challenges facing the industry today. You can read that here for some insight into the state of the art.

A Variety of Methods

Filament printing represents a small part of the capabilities which additive manufacturing has to offer. Among alternatives, the methods to be discussed in this paper are sterolithography (SLA), selective laser sintering (SLS), and fused deposition modeling (FDM). FDM is generally the most popular among hobbyists and is, in my opinion, a fantastic way for young additive manufacturers to master the principles of design alongside the basics of robotics and mechanical engineering which are complicit with all variations of additive machining technology. The next section will give a concise description of these “Big 3” methods and the material they build with.

Fused Deposition Modeling - FDM

Fused deposition modeling is all in the name. This method superheats a thermoplastic past its plasticity point and deposits this semi-fluid in thin layers onto the print area. These semi-fluid layers fuse with each other before cooling, hardening, and forming the desired model.

Materials used are thermoplastics and thermoplastic variants like ABS (acrylonitrile butadiene styrene), PLA (polylactic acid), or PETG (polyethylene teraphthalate glycol). The reality, as we’ll discuss further below, is that any thermoplastic or variant thereof is capable of being applied through fused deposition modeling. Often used are also unique materials which combine non-plastic materials with the thermoplastic: wood, rubber, or carbon fiber to name a few.

Key components of this method are the heated build plate (or print bed), nozzle (or hot end), and the extruder. The extruder controls the speed at which the thermoplastic is “pushed” through the hot metal nozzle, which melts the material. The melted material flows through the nozzle and is deposited onto the build plate.

Stereolithography (SLA)

SLA printing takes a different approach to the process by utilizing various frequencies of laser emissions to induce the hardening and bonding of a photopolymer resin. The laser moves through a layer of resin which cures and hardens to form the desired pattern of the layer. The print area is then shifted, progressing through the z-plane and positioning the print bed for another layer of resin to be hardened in the desired pattern.

In contrast to the heat-reactive thermoplastics used in FDM, stereolithography utilizes photopolymers which are reactive to ultra-violet light (emitted by laser).

Key components of SLA are the vat of resin, the curing laser, and the build plate.

Selective Laser Sintering (SLS)

Selective laser sintering uses a high power laser to superheat and melt a bed of fine metal powder. As the laser sweeps across the bed of powder in the desired pattern, the tiny metal granules are melted together while the powder which is not affected by the laser can be easily swept away. Upon completing one layer pattern, the machine lowers the print bed and lays down a new layer of powder, covering the model. The laser then sweeps over the new field of powder, fusing the next pattern onto the previous. The process repeats fusing and re-applying until the model is complete.

This method graduates the additive manufacturer out of thermoplastics and photopolymers and into the glorious realm of sturdy and conductive metal.

Components of note in this method are the print bed (which must be susceptible to the high-powered laser itself), the laser, and the method of application for each new layer of powder.

The Frontier

With this understanding of how the methods work and what their crucial components are, we’ll next look at where the industry is currently lacking and the direction in which we can best move to take advantage of fresh information. D’aveni and Vankatesh discuss this frontier in terms of hardware, software, and management systems. In agreement that these three subjects are huge and currently “under assault” by the AM world, I want to also open the conversation on this frontier in terms of materials science.

Between these three methods (FDM, SLA, SLS), we can print across a wide range of materials. This is part of the challenges facing additive manufacturers today: there are too many materials which have not yet been properly documented and integrated. With additive manufacturing being a relatively new technology, the vastness of materials to be documented is just that: vast.

The industry is on the verge of an explosion of understanding. The fuel of this explosion is research by chemical engineers testing the limits of the periodic table in additive manufacturing applications. To fully realize the capabilities of additive technology, a library of materials should be compiled. This will document the ways in which different compounds of chemicals and materials interact with heat and across various ranges of the electromagnetic spectrum as these are the main catalysts of additive machinery (see the Big 3 methods above).

A manufacturer with this materials database will have a significant leg up on competitors across not only the additive manufacturing field but also the traditional manufacturing field. The dominant AM organization will have a strength of agility as they are able to rapidly shift production between material and machining types. Mastery of the elements will give the production management system almost unlimited possibilities, or manufacturing possibilities which are limited only by our current knowledge.

Much of the decision making can be handed off to an application of that database, much like 3D printers use a slicer software to produce the GCODE program for each individual model they create. The process will have initial parametric design input from the user, but with deeper digital construction and preparation determined by the program and reviewed by the user. As the system is capable of processing the necessity of chemical compound mixtures far more accurately than a human the materials database will allow the utilizing company to shift production with agility, assuming that they’ve invested as much research into their additive machinery as well.

Conclusion

This technology of additive manufacturing is young and exponential, both indicators of an industry ripe for investment. By developing a foundation of the principles, methods, and materials and following the right leader, a nimble team can use this technology to disrupt an industry of titans or to build in ways which no humans have before.