Stratasys eliminates the Z axis limit in FDM 3D printing
Who would have thought that you could get 7 ft, 20 ft, and longer parts from an extrusion 3D printing process? The Z axis handles height, and for certain builds, not only would the build time be agonizingly slow, you would need quite a support structure to handle tall parts.
But Stratasys Ltd. found a way to use its Fused Deposition Modeling (FDM) process to produce very long parts. It will show its Infinite-Build 3D Demonstrator at the IMTS Show this September.
What Stratasys engineers did was turn the Z axis on its side. The build plate is oriented as if it were a vertical wall, and the extrusion nozzle deposits material on that “wall” layer by layer. Thus, the part can “grow” out of the machine, coming at you on its side, to whatever length is needed, an almost infinite Z.
This in-situ view of the Infinite-Build 3D Demonstrator shows the Z axis nozzle placing material onto a part that is placed against the build table, which is positioned as though it is on a wall.
The bottom floor of the machine’s build area is 7 ft; parts longer than 8 to 10 ft may need additional support. That support can be in the form of a table that the growing part will rest on as it grows, or it could be an overhead crane holding the part and moving with it as the part grows.
Build speed is 10 times faster than current extrusion processes, claims Stratasys. Part of the build speed comes from the use of linear motors to move the FDM nozzle. Another part is the use of a screw-based extrusion deposition nozzle. It is literally a specially designed screw that takes the micro thermoplastic pellet feedstock, melting the pellets within until they melt together just before deposition.
Plus, there’s an in-situ process control system that lets you see what is going on inside the build area.
The machine was designed for thermal control. Temperatures are higher near the extrusion nozzle. As the part builds and extends outward, the temperature gradually drops for part cooling.
The aerospace industry is looking into this machine, as well as the automotive industry. It has already been used to produce internal airplane side panels with window openings. The material used produces lightweight thermoplastic parts with repeatable mechanical properties. The initial material is Ultem 1010.
Stratasys worked with Boeing in the development of this machine. The airplane builder is currently using an Infinite-Build 3D Demonstrator to explore the production of low volume, lightweight parts.
One of the complaints made about extrusion processes, like FDM, is the limited size of parts. It looks like Stratasys Ltd has found a unique and interesting way to address this concern.
Leslie Langnau
llangnau@wtwhmedia.com
