The largest 3D print I’ve ever seen was produced by Thermwood.
I first ran across Thermwood at an event a few years ago, where they explained their then-new 3D printer. The company historically produces large-scale CNC machines. And by “large-scale”, I mean enormous, almost building-sized devices. At that time they were just starting into 3D print territory.
Now, more than two years later, they seem to have found their niche and are filling it well. They have several products in the field being used by live customers for production use.
The systems they produce are quite impressive, with a standard build area of 3 x 6 meters (!) and going up to 3 x 12 meters. Yes, I did say building-sized.
To accommodate such enormous prints, the Thermwood system incorporates several unusual features. First, it is a pellet driven system, which not only lowers the operational cost significantly as pellets are far less expensive than filament, but also provides for speedier prints.
High Speed Pellet Printing
The system includes a large screw that drives pellets rapidly into the 40mm long melt core. Faster printing means the rapidly flowing thermoplastic is exposed to the hot zone for less time, and thus by making the melt core longer, the heating time issue is resolved.
Two extrusion nozzle sizes are provided: a huge 5mm nozzle, and an absolutely enormous 21mm nozzle, which seems appropriate given the massive size of this 3D printer. I don’t think I’ve ever heard of a thermoplastic nozzle even close to the 21mm size.
Thermwood says they can print up to 90kg per hour using their 40mm melt core, and up to a spectacular 180kg per hour with their larger 60mm melt core. This is a truly enormous amount of thermoplastic, and likely operators of the system will quickly consume pallets of pellets at a time.
There are two other interesting features to their extrusion process. As you might imagine, pushing out this much material at rapid speeds will result in a less accurate bead, and that is in fact the case. Thermwood’s system adds a roller that follows the nozzle and presses the fresh extrusion down to a consistent height. This means that extrusion and pellet issues do not accumulate layer by layer as the print proceeds.
Secondly, the system includes a built-in CNC mill that smooths the sides of the bead. This corrects the side accuracy, and in the process leaves the print with a very nice surface finish. All of these features together form a 3D printing process Thermwood calls Large Scale Additive Manufacturing, or “LSAM”.
Hybrid 3D Printer and CNC Mill
The system includes a number of other convenience and reliability features such as fume and dust extraction, servo motor drives, thermographic imaging and a drying system.
The results of all these features are rather amazing large-scale prints, as you can see in the image at top. This particular print is a mold for carbon-fiber layup to produce a helicopter blade. The print is only one half of the mold, as a corresponding unit would be placed on top.
As you might imagine, the ability to produce such enormous molds is tantalizing to industry, particularly the aerospace industry, who can produce the molds at a far faster elapsed time and at lower cost.
If you’re interested in acquiring one of these massive industrial 3D printers, be aware the pricing of these often-custom built systems starts at around US$2.2M for the 3 x 6 meter version.