Behind the scenes at re:3D - the HGBX

The re:3D team works hard to bring frequent updates and upgrades to our community, but we also have long-term projects going on back in the lab - testing out new ideas, techniques and hardware that may figure into the product line further down the roadmap.  Thanks to support from the NSF SBIR Phase IIB Supplemental Award, one of those projects is the HGBX - a prototype version of the Gigabot X pellet printer that will be capable of printing ULTEM™ and other high-performance polymers.  These engineering-grade thermoplastics require several conditions, including an actively heated chamber and higher extrusion temperatures.  How about a sneak peek at some of our progress?

First, the HGBX extruder.  The standard Gigabot X extruder has three blocks with 80W/24VDC cartridge heaters to create multiple thermal zones along the extruder.  (Having different temperatures in the feed, compression and metering sections of the barrel is typical for thermoplastic extrusion devices.)  For the HGBX prototype, we’ve replaced those heaters with 175W/120VAC band heaters.  

Figure 1: Gigabot X Heater Configuration (left) and HGBX Heater Configuration  (right) - without insulation.

As you can expect, with 175W heaters the extruder reaches higher process temperatures and can do so much faster than with the standard configuration.  The graph below is a bit busy and takes data from two different test purposes (so it’s almost apples-to-apples), but you can see that the HGBX reaches a temperature profile typical for processing ULTEM™ in about 7 minutes, where the standard Gigabot X is going to take at least 20 minutes to stabilize at a lower temperature profile (in this case for polycarbonate).  The step at the end of the HGBX run demonstrates that the prototype extruder can easily reach 400°C or beyond.  Note that this comparison was done with the extruders static (i.e., not extruding.)  Extrusion testing on the HGBX will begin soon.


Figure 2: Comparison of the heating rates between the Gigabot X and the HGBX extruders.

As for the actively heated chamber?  We’ve got one of those too.  We’ll save the details for another post, but here’s a photo to give you some ideas about our design.

Figure 3: HGBX heated print chamber - or maybe a pizza oven.  You decide.


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