What’s stopping mass production with 3D printing? And what are some of the solutions?
The roadblocks to mass production with additive manufacturing are not insurmountable, but they are considerable. Issues like production speed and part consistency are preventing additive manufacturing from becoming the industry standard for mass production. Several leading-edge companies are winning with mass production using additive technology. Fast Radius is one firm that is addressing the challenges.
Mass Production with 3D Printing: It’s About Time
Compared to most production processes, additive manufacturing remains a time-consuming endeavor. Depending on the size and complexity of a part, it can take anywhere from a few minutes to several hours to print, not including post-processing. While newer technologies like Xerox’s liquid metal 3D printer can rapidly print aluminum parts, the industry is in many ways still developing. Companies adopting additive as a production tool find that the learning curve is steep, especially for complex parts and critical applications.
Another major hurdle on the road to 3D printing mass production is a lack of experience. Companies are often interested in harnessing the numerous benefits of additive manufacturing. However, they frequently lack access to the technical know-how and machine operation skills to truly take advantage of this budding industry.
“For other kinds of manufacturing—for example, CNC machining or injection molding—there’s really a lot of expertise in the world because those technologies have been around for many decades and they’re huge industries, so there are lots of people who know what to do,” explained Bill King, co-founder and chief scientist at Fast Radius. “For additive manufacturing, you see many companies interested in pursuing production opportunities, but they just don’t know how to get started, or design the parts, or interact with the supplier, or evaluate a quality system.”
The largest obstacle to mass-producing with 3D printing is arguably the lack of consistency within printed parts. There are many different types of additive manufacturing techniques, from laser 3D printing to using pressurized gas to eject powdered metal at supersonic speeds. However, even identical forms of 3D printing produce parts that are different. Even parts produced with the same machine can vary from one another based on tray location, the material used, and other factors. Often, this presents the added problem of post-production where the part has to be further refined for precision—which can be time-consuming.
“When you read about additive manufacturing in literature or in the popular press, you would think that additive manufacturing makes the same part the same way every time. You don’t really learn about the variabilities,” said King. “If I have two machines that are identical and have identical process settings, you would think that those two machines would make identical parts. That’s not true. Parts that come from different machines are different. Now, those variabilities can be small and we can control them and make them acceptably small in production. But there are differences, and that’s really been the focus of our technology developments.”
Another issue affecting part consistency is that, at its core, additive manufacturing operates on different operation processes than conventional manufacturing. In most manufacturing industries, a specific machine produces a specific part repeatedly. This allows workers and engineers to easily monitor and mitigate the factors contributing to variation in parts. With additive manufacturing, however, a single machine produces a wide variety of parts with diverse geometries. This makes it extremely challenging to establish a printing standard and part consistency, as different applications place different GDT demands on designs. A jet engine component may be made with the same process as a cup holder, but with very different accuracy and repeatability requirements.
Speeding Up 3D Printing
While bigger build volumes can address the relatively slow build rates of most additive processes compared to machining or molding, print speed is increasing with new technology. HP’s Multi Jet Fusion (MJF) and Carbon’s Digital Light Synthesis (DLS), for instance, are new approaches that avoid the limitations of conventional moving print heads or lasers for high-speed printing.
Unlike many other 3D printers, HP 5200 uses the entire print tray for printing. As much as 4115cm3 of material can be deposited per hour along the entire surface of the tray, accelerating production time. Much like inkjet printers, the HP 5200 works by depositing a single layer of material after which a single pass of heating is applied to the layer to fuse it in place. The temperature at which heating takes place is calibrated based on the material used. If the part is comprised of different materials, a fusing agent is applied at the location where the fusing has to occur. Detailing agents are also applied to ensure part precision. Once both fusing and detailing agents are applied, the heating takes place. This process is repeated layer after layer to 3D print the part.
The Carbon L1 printer uses Carbon’s patented digital light synthesis technique, previously known as continuous light interface production (CLIP). In DLS, a UV light image in the cross-section of the part is flashed on curable resin. This resin is stored in a specialized container, the bottom of which is made of an oxygen-permeable material. A platform is lowered into the container, leaving an extremely thin layer of resin between the platform and the oxygen-permeable material. This layer is called the “dead zone” because oxygen prevents the resin from curing when exposed to UV light.
When the light is flashed, the resin directly above the dead zone is cured in the same pattern as the UV light and sticks to the platform. The platform is—very slowly—lifted out of the container, allowing more resin to flow above the dead zone and get cured by the UV light. This becomes a continuous process as layer after layer of hardened resin attaches to previous layers joining the rising platform. The result is a rather mesmerizing additive manufacturing process where a geometrically complex, semi-solid resin object rises out of a shallow tray of liquid resin. Once separated from the platform, the object is then heat-treated to fully harden.
That said, fused filament fabrication (FFF) remains one of the most prevalent 3D printing technologies due to the inherent speed of the process. At its core, FFF involves feeding thin spools of thermoplastics into the printer. These thermoplastics are then melted (usually with lasers) and the melted material is precisely layered onto a tray. Much like with a glue gun, layer after layer of this material is laid onto the tray until the desired shape is formed. The Delta WASP 20×40 Turbo 2, frequently considered one of the fastest 3D printers in the world, uses FFF to produce complex shapes in record times. Other 3D printers known for their speed, like Anycubic Mega S, Ultimaker S5 and FLSUN QQ-S, all use FFF and have mass production potential.
Prototyping Innovation
Despite the ability of design software to render and simulate complex parts with high fidelity, there is no substitute for a prototype. From functional prototypes for fit check or process qualification to samples for marketing and sales, they’re an important part of any product development process. Very frequently, validation and testing don’t need expansive production materials, making additive a very economical option.
Testing concepts in advanced design has become a staple of rapid prototyping with 3D printers. While working on microfluidic diagnostic cartridges for COVID-19 testing, however, Fast Radius had a revelation.
“Prototyping for microfluidics is actually very easy, but production is really hard,” explained King. “It usually takes years to develop a microfluidic system that is capable of scalable production. The reason for that is that prototyping and production are done with different materials and manufacturing process technologies, and the geometries that are desired are really hard to make. Our insight was that we could do prototyping and production on the very same equipment and materials.”
By working on the prototype using the same geometries and material as the final product, Fast Radius was able to circumvent the revisions and fine-tuning that would normally go into processing the final product.
Accuracy and Repeatability: It’s About Control
Another way of ensuring part consistency is through software controls and monitoring capabilities. Fast Radius is addressing the precision issue in 3D printing through their software technology stack, Fast Radius Cloud Manufacturing Platform. The cloud-based software gathers measurement data from Fast Radius factories and analyzes it for optimization and data quality purposes. This informs Fast Radius’ prototyping capabilities whilst streamlining their ability to mass-produce parts.
“The Fast Radius software platform allows us to do that at scale, and specific variability and quality control technology is an important part of it,” said King.
Data gathered by the Fast Radius Cloud Manufacturing Platform can come from a variety of sources. In a recent study to inspect part variation in 3D printing, a simple high-resolution document scanner was used to take thousands of detailed scans of parts’ size, geometries and other features. These scanned images were then fed to the platform, which was able to conduct a detailed analysis of the parts without it being too computing intense.
When it’s all said and done, however, the quality of a printed part normally takes priority over quantity. While the potential of mass production gets closer to fruition every day, current technology offers plenty of benefits: geometric complexity, dimensional stability, and a wide range of materials from low modulus elastomers to refractory metals—many identical to those used in production.
“What we need is to be able to combine process control with the evaluation of parts that come out in the end,” stated King. “Because what the user cares about is, ‘Are my parts good?’. That’s what our focus has really been on—ensuring that the parts we make satisfy customer requirements.”
To learn more about Fast Radius, visit their website.
