Joining 3D filament ?

[John Doe 2Participant @johndoe2]

Sometimes when printing, we come to the end of a filament reel and need to feed a new reel in, mid way through a print.

Normally I just feed the new filament into the extruder motor port while the printer is printing and this works, but until the new filament is completely through all the way to the nozzle, any filament retractions cannot work – all that happens is that the new filament retracts inside the Bowden tube but obviously doesn’t pull the last piece of the old filament back.

Can anyone suggest a way of successfully joining filament ? I have tried various plastic glues and hot-gun glue, but none seem to work.

[Peter Cook 6Participant @petercook6]

You could heat the ends of both filaments sufficient to melt them, press together and then clean up the joint before resuming printing. However I doubt that you would be successful.

Far more successful would be to pause the print, remove the remaining bit of the old filament, insert the new filament, purge and resume printing. Most printers will have the facility in the user interface to do this – many people do it to change colours during printing.

[FulmenParticipant @fulmen]

Is that really a problem? As long as the feed pressure is released the material extrusion should stop as well. As for joining filament the simplest and safest option is to melt them together. here are some ideas:

How to Join, Fuse or Splice Filament Together

[Steve FParticipant @stevef]

There a quite a lot of filament joiner tools around. They just hold the filaments to be jointed in the correct position. You heat the ends to join them. The tool can the be opened to get the filament out.

There a few ideas on thingiverse. Useful for people who make filament from plastic bottles. Search for “petamentor” if interested. There are other projects also with their own ideas.

regards

Steve

 

 

[Anonymous]

Quite a few on Amazon under < filament joiner >.

[John Doe 2Participant @johndoe2]

Ah, thanks all. It never even occurred to me to ask Mrs Google !

What Fulmen and SteveF found looks to be just the job !

I had already tried what Peter Cook suggested but the ends did not bond securely – with me just holding them.

And pausing the print to remove one filament and insert another has several pitfalls. One is that the print can cool too much to bond properly to the next new layer of new filament – after it has cooled down during the filament swap.

Another is the risk of disturbing the Z height by removing and inserting filament – the filament feed stepper motor is mounted on one end of the X/Z gantry, and can be accidentally moved in Z if you’re not very careful.

And if you cannot easily join or feed new filament in, you end up with lots of reels, say a quarter or a fifth full. You don’t want to risk there not being quite enough filament for your next print, because you cannot easily measure how much is left; and if you can’t join them during a live print, you can’t use all these end-of-reels, which is very wasteful. I have had some success feeding them in without joining them, but as I say filament retract then doesn’t work, and sometimes the next piece of filament jams in the mechanism and leaves the nozzle with no filament feed, as happened today, and it missed a whole layer while I frantically tried to feed the new piece in but it kept jamming.

I am also going to design and make a reel to reel feeder, so I can measure how much filament I have left on a reel-end.

Hence me asking the question, and thanks for the answers.

[HowiParticipant @howi]

My printer will pause if filament runs out, just do a filament change and carry on, no problems yet!

 

[Alan Wood 4Participant @alanwood4]

Here is the method I use for joining filament using silicon tubing.  Seems to work well.

https://altrish.co.uk/2023/04/23/joining-pla-filament/

 

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