Filament Explosion

MentallyInept · October 4, 2021, 4:00pm

Hey People,

I’ve got a reoccurring issue, where filament exits out the the top of the heat block, filling up around the fans.
Someone directed me to a video which mentions a lose connection threading in to the heat block. I have since repaired but it has come back a month later, worse.
A photo is attached but might be hard to see; black filament on black printer.

Any advice for a more permanent solution would be appreciated.

LEGOManiac · October 4, 2021, 5:52pm

I can’t tell if that’s a direct-drive or all-metal hotend or not. On the assumption that it isn’t, the Bowden tube must be carefully cut at 90degrees and inserted all the way down to the nozzle or heat break (if it’s an “all metal” hotend). Similarly, the heat break itself must be threaded down far enough that it makes solid contact with the nozzle. The nozzle must also be tightened when hot as the heating of the heater block will cause the block to expand and can produce a tiny gap. It’s amazing what liquid filament under pressure will ooze into.

https://cults3d.com/en/blog/articles/psa-hot-end-cleaning-assembly

kitedemon · October 5, 2021, 1:36am

Lego has that right. Make certain everything is at 90º also the bowden tube is the right lengh and not too short.

Glenn · October 5, 2021, 1:51am

I’ve never had to do this on my B1 but lots have and reported it works well.

the fellow who made that has some custom firmware and also a mechanical setup guide that will help you get the best out of the printer.

gist.github.com

https://gist.github.com/looxonline/808a204f4f881462403f2baeefc1f69b

biqu_b1_getting_started.md

# Getting started with your B1

Congratulations on getting a shiny, new B1. It is a great machine for beginners and experienced users alike but like all machines you will need to do some things just right to get the most out of it. This is a brief guide which explains how to put together your B1 to ensure that the mechanics will just work.

## Installing the uprights

When installing the uprights it is crucial that they be at 90 degrees to the **base** and not the bed. The bed will be sorted out later. If you fail to ensure this then you are likely to experience later issues with ABL and/or the nozzle scraping across the print.

In order to ensure that both uprights are at 90 degrees you will need to use a set square. Eyeballing it alone is not enough and relying on the provided brackets is also not enough since they include some play by design in order to allow you to manipulate the frame to overcome manufacturing tolerances. Place the set square up against the frame and the base as can be seen in the image below (note that it is not pushed all the way against the frame in the image but you should) and ensure that both sides of the frame are a perfect 90 degrees.

This file has been truncated. show original

Nynexx · October 5, 2021, 8:17pm

make sure you filament is dry, it can absorb water over time out of thin air. This causes the filament to pop and crackle making for a stringy mess.

MentallyInept · October 5, 2021, 10:37pm

Thanks for the replies, everybody!
I’ll keep these in mind when I crack into my block of plastic.

kitedemon · October 6, 2021, 8:33pm

That is a terrible mess, it looks like it is going to be filling much of the cavity behind the plastic shroud. It might be worth pricing a new extruder unit. Then if you damage something of take a long time cleaning this one you are still printing and have extra parts.