Sags, supports, and sticky strands
Sags, the need for many supports, and sticky ooze strands can be big problems while printing 3D projects. For Jeff Parish, a mechanical engineer who has developed many of the awesome features for our 3D printers, the solution came in the form of a part cooling system.
The original RigidBot (RB1 series) had no part cooling fan at all. That is what initially drove the development of a high efficiency part cooling system, Jeff said.
The Part Cooling System
Jeff’s design uses a high-pressure radial blower to direct a concentrated air flow right at the tip of the nozzle, parallel to the surface of the print. This quickly blows the heat away from the print without causing temperature fluctuations in the heating block, and both near and far side features are cooled effectively.
Jeff tested his part cooling system with a bridge torture test, and shared his successful results on Thingiverse.
The proof is in the results
The end result? A part cooling system that allows 15mm bridge spans at full print speed with less than 0.1mm of sag, and horizontal overhangs 5mm straight out and 3mm wide that are flat by layer 3-4 printing with 0.1mm layers. Intense overhangs can be printed with little to no curling as low as 30 degrees with 0.1mm layers and as flat as 20 degrees with 0.05mm layers.
Typical printer torture tests are no problem with this part cooling fan duct system. This torture test, posted by Jeff on Thingiverse, was printed on an RB2 without supports or curling issues.
Jeff Parish said, “The ooze control benefit comes in very handy when printing with dual heads. The idle head tends to ooze while waiting its turn to print on a layer and having the part cooling fan blowing full speed on the nozzle tip keeps the ooze to a minimum and cools any strands that do form to the point that they break off or don’t stick to the print.” (Cone on Thingiverse).
A part cooling system for RigidBot 2
Later, when the RigidBot 2 printer was developed, the part cooling fan design for the RB2 proved to be ineffective. Because the blower hit a 90-degree turn, the air came out at a 45-degree angle and missed the nozzle completely. After attempts to design a workaround were unsuccessful, Jeff redesigned the RigidBot 1 part cooling fan so that it would snap onto the RigidBot 2 carriage, allowing the RB2 printer to have the same great performance as the RB1 printer. The part cooling duct system is now standard on all ReliaBuild 3D printers.
Jeff says the maximum bridge length he has tried is 96mm (that’s over 3.75″) with only 0.3mm of sag, and one string to remove. This is awesome stuff!