Grégoire Saunier
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BearExxa V2 - E3D Revo Micro
🕑 Added 2022-02-13 11:36:31 +0000 UTCThe BearExxa V2 is based on the new E3D Revo Micro with stock fan. I don't think it is interesting to list again all the advantages and features of the Revo but I hope you will see few extra through these lines.
The Revo Micro is very compact and it has allowed us to reduced the filament path drastically from 83mm on BearExxa V1 to 76.9mm on V2. It is shorter by 1.35mm than latest Prusa MK3S extruder. In case you are wondering, the Bondtech extruder for Prusa has a fairly long filament path of 88.65mm. Oh and while our distance is short, we still have the print fan in vertical for longer lifespan, more fresh air and to grab less hairs from the prints.
We also choose to go with the stock E3D Revo Micro tiny fan. It helped us to make a light and compact build but it is also a good balance between noise and performance. Having a fan corresponding to the size of the heatsink is improving the hotend cooling which results in a lower extrusion inconsistency and sharper retractions.
The tiny fan size and the compactness of the heatercore allowed to have more space around the heatbreak which is then surrounded by extra fresh air that helps to have sharp thermal transition. This is also helping to improve print quality of small printed part (where the extruder stays all the time on top of the it) by allowing a better cool down of the latest layers.
This fan has unfortunately a downside, it does not have a third wire for the rotation feedback. This means we will need to disable the fan check from the LCD menu and temporarily plug your old Noctua/Sunon when running the self test. However, we have several ideas and will work on finding a solution regarding this point.
Groove mount isn't dead... Yep you read that correctly xD . Sanjay, we hope you pardon us from where you are! During the beta phase we have tested many ways to assemble the hotend in the extruder body with the screw mount (we have shared some designs on the latest picture if you are curious) and we have identified few issues with it:
- it takes a lot of place to use the big M12 nut as you need room for fingers/tools (however, it is good for bowden setup)
- it can get unscrewed when you change the nozzle
- if you 3D print a thread you need space for fingers to thread the heatsink and it is not very convenient
To solve all of those points, the best design we could achieve was to use a 3D printed self tightening groove mount! You can install and remove the hotend very easily, easier than with BearExxa V1, and when you close the extruder it does tighten the hotend thread to ensure it will not move anymore. Also note that, due to nozzle swap feature of the Revo, you almost never have to manipulate the heatsink. Groove mount isn't dead but it works very well!
Finally, we like to recommend safe and tested hardware and the Revo Micro is the first hotend we know that comes with the following European directives:
- Machine Directive (2006/42/EU)
- WEEE (2012/19/EU)
- RoHS III (2015/863/EU)
- Reach (1907/2006/EU)
More info here: https://e3d-online.zendesk.com/hc/en-us/articles/4405841037981-Revo-Micro-EC-Declaration-of-Conformity
I hope you appreciate those details regarding all the love we put to design this new extruder. Feel free to ask questions and don't hesitate to challenge us, this is how we all learn and get better.
Enjoy!
Comments
Grégoire Saunier
Oh wow yes Prusa is slowing down the speed of the hotend fan on the Mini, that is not good. During the beta phase some users were running it on a 5V connector on the board but I don't know where unfortunately. That also means it was running all the time if I remember correctly.
Roger Eberhart
Not yet. I’ve contacted E3D support, so will see what they suggest. From the comments on PrusaPrinters for the E3D mount on the Mini, it seems others are running into the same issue. Apparently the fan is undervolted on the Mini, so only running at about 2.4 volts. May explain why it’s so dang quiet 😀
Grégoire Saunier
I print mainly PETG obviously but yes I tried PLA as well as HTPLA and haven't seen this issue. The Revo Micro has sharper retraction so you should retract less the filament than with stock hotend. Have you modified retraction length?
Roger Eberhart
Having been printing with it for a while, I'm getting heat creep issues with the Revo Micro on my Mini. It may be just the way E3D designed their mount. There is no clear path for the fan to blow air through the heat sink. Have you done much PLA testing on the Exxa 2?
