Tip for changing filament without leaving old filament in nozzle

[anaxyd 0]

Hello!

Just thought I should share something with this great community, I have learned a lot from this place, so I feel I have to give something back.

This might already be known, but I give it a try anyways.

I found that the best way to change filament from a color to another, without leaving rests of the first filament in the nozzle, which eliminating the need of priming the nozzle until the old filament rests is gone.

1. Heat up the nozzle to 100 degrees celsius.

2. When it approaches 90-95 degrees, slightly start to rotate the extruder-wheel to pull the filament out of the nozzle

3. When it gets easier and easier to pull (around 100 degrees now), loosen the tightener-mechanism on the extruder so that you can freely pull the filament with your hand.

4. Pull fast with your hand now, and everything should come in one, leaving the nozzle completely empty. (You will see that the tip of the filament is shaped as the inside of the nozzle, when you see this, success!)

5. Now the nozzle is empty, and you can insert the new filament, heat it up to ordinary temperature, prime the nozzle until you see it comes out and viola, you are ready to print! This whole procedure goes actually really fast.

(this might vary from filament-brand regarding the temperature, I am using stock filament from Ultimaker in this example)

I hope this tip can help someone. I surely have helped me a lot when changing filament!

 

[gadgetfreak 7]

I think this is an excellent idea. We've been using "the Atomic method" (based on user MostlyAtomicBob who first explained it) which is similar with the 90C trick.

However, isn't the nozzle reservoir a much bigger diameter than the Bowden tube?

I can't recall the dimensions for UM1 and UM2 resevoir respectively...it would be super cool if it could be automated in the UM2 filament change process.

[takei-naodar 0]

i will try a manual version after my actual print is finished. If successfull i will share the steps and hopefully there will later be an automated process, if there are no failures.

 

[anaxyd 0]

The nozzle reservoir appears to be smaller in diameter than the bowden tube, I have no problems with pulling the filament with the "plug" at the end which is formed as the nozzle reservoir. I can measure the "plug" next time I change.

As far as I can think of, this can absolutely be automated. The extruder have to pull pretty fast to replicate my hand pulling, but it might work really good. Auto-change. That would be a great feature!

I am using the UM Original btw.

 

[IRobertI 520]

Yup, this works great, I've been doing it for a while on the UM2 now. It was one of the reasons I wanted to be able to completely release the filament at the feeder when I started designing my feeder. It can be done on the stock feeder as well, but it's a bit more tedious.

What I did was to heat the nozzle to print temp and then use the move material command to fully prime the nozzle (since the UM2 firmware retracts quite a bit at the end of a print). Then I turned the printer off so that the feeder stepper would stop holding the filament in place. Next you just wait for the filament to cool down (turning the printer back on and going into the "Heat nozzle" menu you can check the temp) and then pull quite hard on the filament.

One downside is that since the roller is still pushing hard on the filament it will sometimes break off the tip of the filament so you have to fish it out of the housing.

 

[gr5 2,172]

One downside is that since the roller is still pushing hard on the filament it will sometimes break off the tip of the filament so you have to fish it out of the housing.

Once you get half way out through the bowden it might make sense to let it cool for 30 seconds and *then* pull it the rest of the way. At 90C the filament is still soft and I'm not surprised it has trouble when it gets to the feeder.

 

[Nicolinux 288]

Interesting discussion. I am changing filament daily (now that I ordered 5m of the entire Faberdashery filament assortment)

With the default material change procedure, strands of filament tend to end in a big blob that won't pass the extruder on the way out. That's very annoying.