Flying Bear Reborn 2 CoreXY Printer

Not too long ago, I purchased a large (325x325x350 print volume) CoreXY FDM printer kit made by Flying Bear (China). This writeup contains some initial observations. Bottomline: I am overall happy with this printer despite some flaws.

In addition to the large volume and CoreXY structure, it is has direct-drive hotend that is capable of temperatures up to 350C, and the price was right at the time (currently $391 Flying Bear website; ymmv). The bed is a fixed, Ultrabase-style glass bed powered from mains (Flying Bear now offers a PEI bed that can be used with their optional induction sensor for bed leveling). Fortunately, the CoreXY structure is preassembled so that printer only takes several hours to put together following online videos (the printed manual is basic).

Picture from the manufacturer’s website.

As can be seen in the picture, the printer has an enclosure with an unusual tent-like cap for the top.
Despite the size of the bed, it heats up quickly (it is A/C powered). I’ve had no problems with part adhesion but have found it necessary to let the bed completely cool to room temperature for larger parts. The default profile speed from the manufacturer is 60 mm/s and the manufacturer advertises a max speed of 150 mm/s. Users report faster printing speeds with Klipper.

The biggest weakeness is the cooling. Not only do the OEM fans easily break (as mine did when it caught on a glob of PETG), but the air flow is directed too far under the tip of the nozzle. People have designed adapters to upgrade the cooling (a MAK Vector duct) or replace the hotend with a Stealthburner. I am still in the process of tuning the printer in part trying to eliminate some very fine stringing. Some have claimed that the thermistor type is set incorrectly in Flying Bear’s implementation of Marlin for the printer, and that it runs hot. I had the best success the hotend on the cool side–typically below the lowest temperature recommended by the manufacturer. The extruder has a 7.5 to 1 gear reduction ratio. I’ve successfully printed flexible PLA (89A Shore hardness) with it.

One of the nice aspects of this printer is that it is easily converted to Klipper. There exists a machine profile on Github and KIAUH simplifies Klipper installation greatly. I currently print PETG at 80 mm/s and plan to test higher speeds with PLA and better cooling.

If you have any questions, let me know!