filament change help  

RE: filament change help

Some times the PETG sticks to the outside of the nozzle and mixes with the next print - I had that problem. If inside the nozzle, try to raise the temperature to PETG setting and purge before shifting back to PLA.

I now have coated Micro Swiss nozzles that is easier to clean.

RE: filament change help

An easy way of cleaning the hot end on filament changes is to use a cleaning filament.  I've been using Rigid Ink Floss for the past year and have been happy with it.  It's an extra expense but it does work well.  There's a few cleaning filaments out there.  This info may be of interest:

https://rigid.ink/blogs/news/how-to-use-3d-printer-cleaning-filament

RE: filament change help

I use a cleaning filament that works from PLA temps all the way to the maximum temp for my MK3S. Since I only use PLA and PETG, I never go higher than that. I always use it when changing type of filament, especially PETG to PLA. Run it through at appropriate temp until it runs clear. I leave a piece in when I am not using the printer for a while. That way I know that it will be ready for whatever one I want to use.

RE: filament change help

Firstly. if your using PETG regularly, you should really consider getting a nickel plated copper nozzle, PETG practically welds itself to brass from my experience but not to the nickel plating on the copper, at about 155 Deg C, any PETG on the outside of the nozzle comes away like a skin in one piece.

Second, as already mentioned, cleaning filament  / floss. Unfortunately RIGID INK have stopped making filament, but there are others available like Technology outlet. Run this through 2 or 3 max loading cycles then unload.

Set your temperature to PLA and as it is dropping from the PETG temperature load in some PLA and again run through 2 or 3 load cycles to purge out any cleaning floss

Now your good to go with PLA.

If changing nozzles or changing to another material from the now loaded PLA, hit reset on the printer to turn off any heating, and watch the temperature dropping from extrusion temperature to 80 Deg C, meanwhile (Depending on extruder, and definitely with PRUSA extruder) slacken the filament clamp so the filament is no longer gripped, and use a folded (More than once) paper towel to wipe away any molten filament from around the outside of the nozzle (This should still be above 160 Deg C at this point). Take care around the heater and thermocouple wires!.

When the temperature reaches 80 Deg C, pull the filament out from the top and it should pull ALL the filament out of the nozzle and you will be left with a clean extruder ready for new filament or a nozzle change. Don't bother trying a cold pull with PETG as you risk lifting your whole printer off the table when you pull the filament up!.

Once you've done a cold pull like this a couple of times, you realise it's easy and gives you clean filament material changes and in my opinion is a must when changing nozzles. You can do a cold pull as well when changing from PETG to PLA, but since I went to a copper plated nozzle which works with PLA as well, I never have any remaining PETG after running the floss through and purging with fresh filament, but if going from Polycarbonate to PLA, I will do a cold pull just in case due to the temperature difference between filaments.

If you order a new nickel plated copper nozzle from E3d, then get yourself some silicone socks as well, the ones with the bigger hole, the V6 Silicone Sock, fit it  being careful of the wires, run a PID nozzle calibration and enjoy a much cleaner heater block and more consistent nozzle temperatures.

RE: filament change help

thank you i never even knew there was a cleaning filament, i will try and find some in the uk , i use a hardened steel nozzle for printing abrasives also so dont think a copper nozzle would work ?

RE: filament change help

I use Nylon Bridge from Taulman3D as cleaning filament - works fine for me and is easy to get.

RE: filament change help

Posted by: @keithcowell

thank you i never even knew there was a cleaning filament, i will try and find some in the uk , i use a hardened steel nozzle for printing abrasives also so dont think a copper nozzle would work ?

You can find hardened steel nozzles that are coated. E3D's Nozzle-X and P3-D's Hercules series work well. The Nozzle-x is meant for higher temps, so may cost a bit more. Both are excellent.

RE: filament change help

Here is my experience with the cleaning filament that I use is after purging through the nozzle until clear (this stuff when flowing is clear, goes milky when solidifies) I do at least one cold pull with the cleaning filament. I'm not sure if it is an inferior cleaning filament or if this is normal, but this process seems to work well for me.

I start purging at the print temperature of the previous filament type used, and step up to 280° (max temperature for the cleaning filament) in 10°-15° steps intermittently purging to try to encourage any stubborn residue to loosen. I then do a cold-pull with that filament (after letting the extruder cool off at least until the heatsink fan stops running). Often I find crumbs of the old filament (especially near the top of the nozzle) in my first cold pull. I keep repeating cold pulls with the cleaning filament until I don't see anymore crumbs. I find that the cleaning filament releases from my nozzle (TC nozzle and plated copper heater block) and pulls out easily around 90°C, so any other filament crumbs that get embedded in the cleaning filament haven't gotten warm enough to do anything other than get a little soft. The most amount of cold pulls that I've had to do so far was 3 after changing out of a CF filled PLA.

RE: filament change help

Be sure you read and understand ant manufacturers nozzle warranty ( if you think you want to use the warranty).

E3D specifically states that the warranty on Nozzle-X is void if they find evidence of cold pulling. Beyond that, only you can decide what is best for you based on all available information you have. Ask 100 people and you will get 100 variations of the answer. Key take-away is that you don't want any residual from the last filament type left in the hot end.