Recently I had a chance to visit the world market leader in 3D printing, Stratasys, together with my students. We went to their location in Rheinmünster, Germany, near the Baden-Baden airport. While I always keep a bit of an eye on new developments in 3D printing, it was quite refreshing to get an update on the latest developments from the source. In this first post I will look in more detail at their different printing technologies, before I look a bit into their markets in the second post.StratasysStratasys is a company that was founded in 1988 and has thirty-five years of experience in 3D printing. In 1994, they released their first available thermoplastic printer. Another breakthrough came in 2007 when they released their first multi-material printer. In 2008, they released their first 3D printer for industrial production, and in 2014, they released a multi-color 3D printer. As of 2024, Stratasys has over two thousand employees worldwide.Fused Deposition Modeling (FDM)FDM prints parts in layers by heating and pushing out polymer filament. This is the oldest and most established technology at Stratasys, and their main source of income.They can print objects up to 1000 x 610 x 610mm, or 372 liters. The workspace is temperature-controlled for better accuracy, so the climate doesn’t affect them. Their newest machine can switch between fine nozzles for the part and coarse nozzles for the support. They also have four nozzles to choose from different materials and water-soluble supports.One use of FDM is tools for foam inserts. If done with aluminum, these tools need lots of small holes to let the air escape, which is expensive. FDM, however, can be made permeable to air by simply putting the layers in different directions on top of each other.Another use is robotic grips, especially for lighter co-bots. These can include pneumatic tubes in the 3D printed part, which otherwise are a bit more difficult to make. They have materials that approach the strength of aluminum, albeit much lighter, but not as temperature resistant. Ford uses a DFM tool to install lug nuts. Bending tools for low-volume bending can also be made with FDM. The German ICE train includes air vents in FDM for their dining cars. Another use is spare parts for the Berlin tram system, where it is otherwise difficult to get spare parts for sixty-year-old vehicles. Here, FDM is used to make new bumpers.PolyJetPolyJet 3D printing, also known as multi-jet modeling, is a technology that uses polymer droplets similar to an inkjet printer. Unlike a typical inkjet printer, which has four colors (Cyan, Magenta, Yellow, and Black), PolyJet also has white, transparent, and flexible materials. This allows it to print in pretty much all the colors that an inkjet printer can, but in 3D, plus transparent and flexible. PolyJet printers are available with five to seven different materials that can be printed simultaneously.PolyJet is one of the few 3D printing technologies that can print in color. It is also the only 3D printing technology that can easily mix different materials. While FDM can switch filaments and some FDM machines have multiple filaments and nozzles, it is still much less flexible than PolyJet.The maximum object volume for PolyJet is 1000 x 1800 x 1500mm, or 2.7 cubic meters. It can print objects from different materials and colors, including transparent ones. One of the most impressive uses of PolyJet is in medical models, where organs can be seen within the transparent polymer. However, the material does degrade over time under UV light and turns yellowish.Stereolithography3D printed tower with internal staircaseStereolithography is the oldest form of 3D printing technology. It works by using an ultraviolet (UV) laser or projector to solidify a liquid polymer. The largest printer available for this technology has a maximum object size of 800 x 800 x 600mm, or 384 liters.There are many materials available for use with Stereolithography, including advanced options such as polymers with up to 65% ceramics, which makes them resistant to high temperatures. However, due to the requirements of the UV-hardening liquid polymer, the parts produced can be slightly toxic and are not suitable for regular handling. Despite this, they can be used to create injection molds or thermoforming molds for prototyping purposes. Stratasys claims that their molds can withstand a few hundred shots for injection molding.DLP (Digital Light Processing), brand name Origin OneDLP (Digital Light Processing) technology, branded as Origin One by Stratasys, is closely related to stereolithography. The build space for Origin One is 100 x 150 x 300mm, or 4.5 liters. The key difference between the two is that DLP uses a UV-light projector from below, through a glass pane, to build the object from the top down. This allows the entire layer to be illuminated simultaneously, greatly increasing the speed of the printer.SAF (Selective Absorption Fusion)SAF printing is a technology that uses a polymer powder and an infrared absorbing ink. The printer prints the ink onto the powder, and then an infrared light illuminates it. The areas covered with ink absorb more heat and are sintered together. This simultaneous heating avoids warping issues that can occur with laser sintering or laser melting. The build space for SAF printing is up to 315 x 208 x 293mm, or almost 20 liters.One advantage of SAF printing is its speed. A single layer takes only 11 seconds to print, regardless of the part size. Stratasys claims that a 300mm height can be printed in just 11.62 hours. The resulting parts are airtight, watertight, and oil-tight.SAF printing is used for small parts in the automotive industry, such as plugs, housings, and clips. For example, 400 plugs can be printed in 8 hours, with an additional 16 hours for cooling. Stratasys claims that SAF printing can compete with simple milled parts for quantities up to 4000 pieces, and complex milled parts for quantities up to 250,000 pieces. One interesting example is the filler necks for Daimler bus fuel tanks, which are used as-is with a wall thickness of only 2mm. However, the surface of SAF printed parts is rough, and formic acid may be used to smooth it if necessary.In my next post I will look a bit more into specific 3D printing markets. Now, go out, see if some of your low-volume parts could be printed in 3D, and organize your industry!PS: Many thanks to the people from Stratasys for the detailed information and tour, as well as the samples!
