Alternative hotend assembly and cooling?

[Alex]

Hey,

I wasn’t really happy with the Gridbot 2.5 beta hotend assembly(not that there is anything wrong with it) and have been trying out a few other setups. Mainly EVA 3d, but that required me to use an alternative x-axis mounts among other things, that I wasn’t happy with.
Now I’m on my way back to stock, but I’m having trouble figuring out a new hotend assembly and was wondering if anyone else have any suggestions or alternatives? I was thinking maybe someone else had tried other models/setups.
Thanks!

[Tony_Sexton]

Hello friends! Actual topic. I have already modified my Gridbot a lot. Super printer, Stewart is definitely a genius. But I still can not overcome the problem with cooling, the air flow is too high. I keep trying to upgrade the existing fan mounts, but it doesn’t get better, as a result, reverse thrust begins.

[stewart]

if the air-flow is too high, have you tried using gcode to run the fan at a slower speed?

[Tony_Sexton]

I’m sorry, I didn’t phrase it exactly. The air flow does not go to the nozzle, but to the hot end block.

Would like to get something like this. It seems to me that in this case, the airflow will be ideal.

[Tony_Sexton]

Good range of options
https://www.thingiverse.com/thing:2759439/files

[Tony_Sexton]

How do you like this option? I’m not very good at modeling cool things, so I put a ready-made version from another block. Just make it more compact.

[stewart]

@Tony_Sexton

I’m sorry, I didn’t phrase it exactly. The air flow does not go to the nozzle, but to the hot end block.

Are you basing this on an empirical test or intuition? While it looks like that would be the direction of air flow, it’s more downward than that in reality because 1) the taper of the front directs air down and 2) the fact that the bottom back corner forms a “dead zone”.

I did another bench test today to verify. The third picture shows the air that I could feel on my hand. I tried using thread (pic 5), but it was too heavy to be pushed by the air. Pic 4 shows how the fan sits in the duct. The dead zone is in the bottom corners below the bolt holes. It’s this and the taper of the front that causes the air to exit as it does.

I also checked my printer with the dual fans on. There is substantial air/cooling below the nozzle, but not much detectable around the silicone sock.

I would be hesitant to further reduce or restrict airflow from this type of fan. They’re not designed to operate restricted. Instead, I would propose a notch (bottom pictures) as a way of opening up the airflow more downward.

[Tony_Sexton]

Thanks for the clarification Stewart. But I’m still trying to modernize this solution. I will send samples as a result.

[Alex]

While I found that the stock cooler worked quite well, I was so used to the focused cooling that you are referring to here. I’m using this: https://main.eva-3d.page/
But be aware that you need to modify the X-axis (and parts of the hotend assembly)to be able to mount it on the Gridbot.

Edit: And I am about to build siegfried’s solution as I find it very compelling

Thoughts on Duet Boards for future expansion

Howdy again, just now coming back to this having finally assembled and tested this. I’m not currently hosting the files anywhere, but I’d be happy share more details if you’d still like them. I still need to tweak the design to use the optical endstops stewart suggested. While it’s not really a Grid bot anymore, I tell anyone that asks how great of a place the gridbot is to start. [printerpic]

[Tony_Sexton]

Thanks, I’ll look into this option.