While 3D printers may seem like complicated machines, understanding the 3D printing process and the options out there can help simplify it. While we tend to thrust 3D printing under one umbrella that fails to capture the variety of printers, the process, and the materials utilized to bring products or parts to fruition.
From the different types of printers to the moving parts of the machine to the wide variety of polymers and additive materials used to create designs, understanding how it all works together and optimizing the process is vital to getting the most out of your machine.
While it would be incredible if 3D printers worked like the replicator on Star Trek, how they create objects is no less fascinating. In fact, given the number of moving parts and the printer’s ability to turn a 3D model into a 3D object, 3D printers may just be a touch more impressive.
Perhaps one of the largest misconceptions about 3D printing is that all 3D printers function the same way. In reality, 3D printing covers a variety of processes, and understanding those is key to understanding additive manufacturing.
Material Extrusion 3D printing requires the use of a spool of thermoplastic filament which is pushed through a heated nozzle, melted, and deposited on a building surface or platform in a position based on the 3D model. The filament cools and then solidifies into the final product. Both Fused Deposition Modeling (FDM) and Fused Filament Fabrication (FFF) use this type of process.
Among the first methods of 3D printing, vat polymerization uses ultraviolet light to turn liquid into solid. Layer by layer, the image of the object is projected into the vat of liquid where the UV light solidifies the liquid. Excess liquid is drained from the vat as part of the process until all that remains is the solid object. Stereolithography (SLA), Masked Stereolithography (MSLA), and Direct Light Processing (DLP) all use this process for 3D printing.
This is likely the process most people envision when thinking of 3D printing. Powder Bed Fusion utilizes high-powered beams, usually electron or laser, to melt and then fuse powder material together. The process creates layer upon layer of fused powder until it has created the final product. Selective Layering Sintering (SLS) uses this process as do several 3D printing processes that work with metal including Direct Metal Laser Sintering (DMLS), Selective Laser Melting (SLM), and Electron Laser Melting (ELM).
Material Jetting takes drops of material, photopolymers, and places them on a build platform where they are cured through light exposure. Much like the other processes, the object is then built layer by layer. Because this method works drop by drop, one of its primary advantages is the ability to utilize different photopolymers within the same object, an option that is not typically available in 3D printing processes. Material Jetting (MJ) and Drop on Demand (DOD) both use this method.
Similar to Powder Bed Fusion and SLS printing, Binder Jetting also uses a layer of powder but rather than using beams to fuse the powder, a print head travels over the layer and leaves a binding agent over the layer to fuse and solidify it. The fused layer is lowered and another layer is deposited with the printhead traveling over it to deposit the binding agent. That process is repeated until the object is complete. The only 3D printing type to use this is named after the process itself, Binder Jetting (BJ).
Multi Jet Fusion (MJF) uses technology similar to HP’s wide-format printers. Print heads dispense fusing and detailing agents across a fine layer of powdered material (Nylon, Polypropylene, TPU, etc.). Then, fusing lamps cure the areas where agents have been added and heating lamps maintain the entire process at nearly melting temperatures. This allows the parts to be isotropic in strength across the X, Y, and Z-axis, providing a near-net shape.
Once the printing is done, the processing station helps cool the print job while the integrated vacuum system removes unused powder and stores it to be recycled. Between 80 and 100 percent of the unfused powder can be reused in subsequent builds.
The last stage of the process is the bead blasting station which removes excess powder from the parts and leaves them smooth and ready to use.
As you can see, there is no clear and simple answer to “How does 3D printing work?” as there are multiple processes and then those processes can be further broken down by the material being used to create the object.
While the technology has been evolving over the decades since vat polymerization was first invented in the mid-1980s, the technology and its uses have had a fairly symbiotic relationship in terms of evolution. That is as more potential uses were discovered, the technology evolved to meet those needs and as the technology grew, more applications became clear.
Perhaps the first place for real experimentation with 3D printing capabilities. The first 3D printed organs actually appeared in the 1990s and since then, 3D printing continues to provide prosthetic devices and implants. Further, medical students learning to complete procedures may work on 3D printed parts to give them practical experience.
Similarly, the dental industry finds similar uses for 3D parts as well from implants to instrumentation.
Everything from consumer goods (razors, sunglasses, makeup brushes, jewelry, and more) to industrial goods (tools as well as machine and spare parts) are now being printed on-demand as industries need them and as a way to reap the benefits of 3D printing in terms of cost, speed, and design flexibility.
All three industries are using 3D printing for everything from parts to building entire vehicles. Again, given the cost benefits and the ability for 3D printed parts adherence to tight tolerances and other stringent safety and design standards, the shortened production time makes 3D printing a great solution.
As noted above, medical and dental schools are using 3D printing technology to provide students with low-risk training opportunities. Similarly, much higher education institutions are including 3D printing and 3D printing programs in curriculums to help provide practical experience but also to drive the future of the technology.
There are few things a marketer likes more than the opportunity to show off a new product. Whether it’s at a tradeshow, a conference, or a sales pitch, having a prototype of a product on hand is a great way to entice one’s audience. With the ability to provide rapid prototyping, many companies are investigating how to use 3D printing to give potential partners and customers a hands-on experience with their product before it hits the market.
Given the speed at which the technology is advancing, this is in no way an exhaustive list of who is using 3D printing, nor how they are using it. Some industries are just tapping into the ways they can leverage the benefits of 3D printing within their organization.
Now we get into some of the good stuff. Choosing the material you need for your 3D printing can be overwhelming. Most of what is printed right now is printed using plastics, either filament, resins, or plastic powders. However, some 3D printers are moving into the metal market and starting to produce 3D printed metal parts and products. Let’s take a look at the plastics first.
ABS filament, Acrylonitrile Butadiene Styrene, is an easily molded thermoplastic that also holds a mold quite well once cooled. It is among the most commonly used plastics for 3D printing because of multiple properties that make it useful for various industries like automotive. ABS filament is:
While the benefits are many, ABS has shortcomings as well including that it is not biodegradable and, when exposed to air can shrink which means it must be used in a closed chamber printer to prevent an impact on structural integrity.
Acrylonitrile styrene acrylate is similar to ABS filament and like ABS is sensitive to heat during the printing process but reliable and resistant once cooled. Similarly, it is known for being:
Similar to ABS, it also has some of the same limitations, including:
Polylactic Acid is typically distinguished among 3D printing options as being biodegradable as it is manufactured using renewable materials like corn starch. That the resource from which it is made is a renewable resource, means it is more environmentally friendly than ABS which is made from fossil fuels, it is not biodegradable. It will degrade over time, but is not, as often believed, compostable or simply capable of quick decomposition. In addition to its “green” makeup, it has other benefits including:
Perhaps one of the biggest issues with PLA is that it isn’t particularly resistant to heat. Exposure to heat post-production. That means it has limited applications. Further, while it prints at a lower temperature than ABS, it is not as strong.
PET is Polyethylene Terephthalate whereas PETG includes the addition of glycol which changes the composition and creates a new plastic. The addition of glycol makes the plastic a bit less fragile and comparable to PLA and with the strength of ABS. While PETG and PET are chemically different, they share common characteristics such as:
Polycarbonates include thermoplastics that include carbonates in their chemical makeup. Widely used for applications that call on a plastic’s ability to transmit light such as glasses, Polycarbonates are a great option for engineering and in projects that call for glass or optical effects. While its primary weakness is its susceptibility to water absorption, other strengths include:
As noted elsewhere, 3D printing technology has driven the evolution of supporting technologies such as plastics. High-performance polymers are a great example of developments in this arena. These plastics are in the family of polyaryletherketones (PAEK) or polyetherimides (PEI) and have considerable advantages, especially given their intended use for 3D printing, though they have limitations given their need for a heating plate and closed chamber. However, their attributes make them ideal for the automotive and aeronautical industries.
Polypropylene is a thermoplastic produced from propene or propylene monomer. That it is among the cheapest plastics available means it has a wide variety of uses in multiple industries including the automotive, aeronautical, and manufacturing sectors. Due to several weaknesses like low-temperature resistance and UV sensitivity, simili-propilenos have been created to work around those issues. Even with those drawbacks, it still boasts a few strengths including:
Nylon is a polyamide meaning a synthetic polymer available both in the filament (FDM) and powder (SLS) so it can be versatile. That versatility means it’s suitable for a variety of sectors, but it also offers the following additional benefits:
Resin has properties similar to ABS, however different resins exist for different applications. For example, biocompatible resins exist for use in the dental field. Depending on its application, individuals looking to use resin can likely find one that works for their industry. Because of the variety of resins available, its strengths include:
Hybrid materials take a base plastic and mix it with other elements to provide surface-level change to a material or to add to existing properties/strengths. Typically, hybrid materials are about 70% PLA and 30% hybrid additive. Hybrid additives often include various types of wood which add textured features and metal additives that impact the end product’s finish.
While other options exist and this list is not exhaustive, it covers the primary polymers and materials used in the 3D printing process. Additional materials include composites, aluminide, soluble, and flexible materials. Much like hybrids, those materials work with a base and then include another additive to boost or supplement existing structural properties.
It should come as no surprise that when leading the industry in 3D printing technology, HP has developed polymers specific to ensuring the best performance from their machines and providing you with the best finished product possible. For that reason, HP offers several 3D printing materials solutions engineered specifically for your HP 3D printer.
PA is polyamide or nylon. For HP, PA 11 is made from renewable resources and minimizes waste by providing up to 70% surplus powder reusability which also saves you money. Additionally, it boasts:
If you’re looking for lower-cost printing material, PA 12 may be your solution. It boasts the same reusability as PA 11, but also features:
A highly versatile polypropylene product that enables you to prototype with the same materials as your finished product. Features include:
This material boasts HP’s fastest time to part while offering mechanical resistance and remarkably lightweight parts. Other strengths include:
A highly versatile polymer that produces a full range of colors and white while still providing high density and durable parts. Other features include:
HP also continues to work with multiple partners to develop and provide the best 3D printing materials for your needs, regardless of the industry. There’s much to consider, but optimizing materials for their machines helps to assure your workflow isn’t interrupted by mechanical or design challenges. Further, they can and do work with the industry leaders in the development of polymers and 3D printing additives. This includes preparing for materials in the future such as those with multi-durometer capabilities and metals.
Much like HP’s partnerships, TPM thrives on building strong relationships and partnerships with its clients. If you’re looking to start or build on your 3D printing capabilities and work with an industry leader in the Southeast, get in touch with the TPM team today and start the conversation.