As an industry, additive manufacturing (AM) is seeking to disrupt industrial production practices that have been dominated by injection molding for over a century. Today, we are closer than ever to that reality: sophisticated 3D printing technologies are proving to be a viable means for fulfilling new manufacturing philosophies centered on quick turnarounds and smaller-volume production.
3D Systems’ Figure 4 is one AM technology that has the potential to radically change how plastic parts are produced. Recently displayed at AMUG and RAPID + TCT 2018, the Figure 4 Production system enables digital molding for low- and medium-volume plastic parts. Unlike traditional injection molding, Figure 4 digital molding doesn’t require time-consuming, costly tooling processes.
What is digital molding?
The Figure 4 core technology, patented by 3D Systems’ co-founder Chuck Hull 30 years ago, is non-contact membrane Digital Light Printing (DLP). In the Figure 4 Production solution, the DLP technology is used in a series of connected print engine modules integrated with an automated robotics system to continuously produce plastic parts quickly and efficiently – enabling tool-less digital molding. The modular system is highly scalable and is built for easy integration into automated production lines.
“The modularity of the system is wonderful,” explains Phil Schultz, Senior Vice President of On Demand Solutions at 3D Systems. “It enables 3D Systems to configure the exact right solution for the customer’s needs. For example, the Figure 4 Modular version contains the main control unit and at least one print engine module; the main unit can control up to 24 print engines (there are four print engines in each module). The customized configuration can also include integrated cells for post-processing functions such as curing and washing.”
“The modularity of the system enables 3D Systems to configure the exact right solution for the customer’s needs.”
Figure 4 Production adds automation enabled by a system of robotic arms that carry the printed parts through the manufacturing process, pulling them from the resin vat to the washing, drying and curing modules.
The curing modules in Figure 4 Production are also notable. As Schultz explains, Figure 4 integrates a non-invasive light-based UV curing system which ensures a high level of repeatability and accuracy—especially when compared to thermal curing processes. Further ensuring accuracy and dimensional stability is the configuration’s previously mentioned non-contact membrane DLP technology which alleviates the printed part from all contact and potentially compromising forces (except gravity, of course!).
Say goodbye to tooling
No matter how advanced injection molding processes have become over the years, they are still encumbered by lengthy and costly tooling processes. Taking anywhere from weeks to months, the need to produce molds and other tooling equipment has presented limitations for the manufacturing sector. Most significantly, tooling processes have discouraged anything less than mass production, inhibited customization and limited design and design iteration flexibility.
“[With] digital molding, we are able to go seamlessly into production”
Digital molding, on the other hand, does away with the tooling process altogether, going from CAD design straight to manufacturing. This means that manufacturers can iterate part designs, test them and adjust them for optimal performance without having to add significant tooling costs and, crucially, without adding time to the production process.
“With traditional methods, you need to make a temporary tool and then a hard tool and so on, and each one of those phases carries with it another qualification step. In the case of digital molding, we are able to go seamlessly into production,” commented Schultz.
Let’s talk about cost
By eliminating tooling requirements and speeding up the time to market, 3D Systems’ digital molding system also offers cost advantages to manufacturers. Notably, by eliminating various manufacturing steps associated with traditional manufacturing, digital molding delivers reduced labor, machining, iteration and testing costs.
For low-volume production, the Figure 4 affords the opportunity to save on part production costs. For instance, while an expensive tool will pay itself off with the manufacturing of hundreds of thousands or even millions of parts, the part cost goes up significantly if a smaller volume is required. With its easy scalability, digital molding is much more suited to producing Low-rate Initial Production (LRIP) small-batch runs. This, of course, is conducive to part customization, replacement part production and fast design iteration. For medium-volume production of certain small-scale parts such as dental fittings or automotive clamps, the Figure 4 system’s costs and turnaround times are comparable to injection molding.
Benchmarking the Figure 4
To demonstrate the Figure 4’s competency compared to traditional injection molding processes, 3D Systems conducted a thorough benchmarking study using an automotive vent as the test part. The tests—overseen by a team of experienced engineers and executed by companies specializing in CAD/CAM, machining, injection molding and AM—ultimately showed significant differences in cost and time in favor of digital molding.
Let’s take a closer look at the benchmarking results. Using an eight-engine Figure 4 configuration, the first automotive vent reportedly took 92 minutes to manufacture (the time from inputting the digital file) compared to a 15-day time-to-first-part for injection molding. Subsequent parts were turned out at a rate of one recurring unit every 95 seconds.
At this speed, an eight-module Figure 4 machine is capable of producing 10,000 units of the textured automotive vent in just 11 days. Injection molding, for comparison, would still be in the tooling design stage at this point. For example, once conventional injection molding starts and has produced 10,000 units, Figure 4 will have produced 4,000 more units for a total of 14,000
It is worth noting that injection molding process could catch up to the production rate eventually, with each part taking 55 seconds on average to fabricate.
For this reason, injection molding is still largely beneficial for mass production runs. But for low rate initial production (LRIP) or low- to medium-volume manufacturing, digital molding has the benefit of drastically reducing the time to market for products.
The benchmark tests also show that the estimated costs for CAD, tooling design and tooling labor for the automotive vent were only $121 with the Figure 4 system compared to $4,315 for injection molding. Additionally, by eliminating the need for tooling altogether, digital molding also did away with a $4,850 internal tooling cost necessitated by injection molding.
New hybrid materials
3D Systems’ digital molding technology also addresses another challenge commonly faced by the additive manufacturing industry: material diversity. Thanks to its fast print speeds (measured in millimeters per minute), the Figure 4 digital molding system is compatible with reactive plastic resins with short vat lives. That is because the Figure 4 printers turn out parts at impressive rates; resins are thus not required to sit in the vat for as long, significantly opening up the range of materials suitable for manufacturing. This increased range of materials edges digital molding closer to traditional injection molding by offering manufacturers the material properties they require for a range of applications.
More than that, by integrating multi-mode polymerization, 3D System’s Figure 4 technology is one of the few photopolymer-based printing platforms capable of producing hybrid-material parts. These hybrid materials offer properties such as toughness, durability, biocompatibility, temperature resistance and elasticity that are similar to injection molded materials.
Potential to disrupt
Overall, digital molding and 3D Systems’ Figure 4 system offer the means to produce plastic parts at astonishing rates and low costs for low to moderate volumes. In doing away with tooling stages, this modular additive manufacturing system is in a position to disrupt the machining-based manufacturing field, offering a beneficial complementary solution to injection molding.
So far, dental, automotive and electrical connector manufacturers have shown great interest in the scalable additive system and Schultz believes this appeal will only continue to grow. “We are just getting started,” he says. “The technology itself has so much potential, it’s going to be a game-changer for the entire additive industry.”