Etxruder and nozzle sharing

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Vandal968
Posts: 212
Joined: Mon Jul 13, 2015 4:30 am

Etxruder and nozzle sharing

Post by Vandal968 » Fri Jul 20, 2018 7:59 pm

My M2 has always allowed me to swap filament colors or empty rolls effortlessly while printing. Just let it print and snip the old filament or let the spool run out and chase the old filament down the hole with the new one. Easy peasy. 3x in the last week, I got a jam while attempting to do this. I removed the filament drive and discovered the problem. The hole immediately below the filament guide bearing has worn and it allows the old filament stub and the new filament to create a logjam and get stuck (they both try to go through one hole side-by-side instead of end-to-end). Time to print a new one, and I'm planning on doing it in ABS. I generally print with PLA or PETG, rarely ABS. So rarely, in-fact, that I'm still on my first or second roll of the stuff. I do have two separate hot-ends. Originally, I used to swap between them because I always got a jam shortly after switching from PETG to PLA, although I never had issues going in the other direction. In the mean-time, I've refined my technique and now never have trouble going PLA to PETG or PETG to PLA with a single nozzle.

Questions:
If you are going to share one nozzle across multiple materials, which materials work best through a shared nozzle? Which cause the most trouble when switching between them? Should I use the spare hot-end for the ABS, or is it ok through the same one that I've been using for PLA/PETG? Any tips?

What is the factory infill setting for the drive assy on a V4 extruder?

cheers,
c

airscapes
Posts: 219
Joined: Wed Jan 31, 2018 11:36 pm

Re: Etxruder and nozzle sharing

Post by airscapes » Fri Jul 20, 2018 11:37 pm

From the way I understand it, the issues is different temps for different types of filament.. so if some PETG or ABS is left in the nozzle and you switch to PLA the pits of the PETG or ABS may not melt correctly at a low temp and clog. I have purchased some eSun cleaning filament and run about 100mm of that between types of filament that print at different temps. This cleaning stuff has a really wide melting range so once whatever you were using is all out, the cleaner will all come out when you flush with whatever is next.. And as long as the nozzle size does not change, it is a LOT faster than swamping hot end and setting starting height..
BTW, I think a new drive from MG with bearing is only $20.. Where did you finde the V4 drive file?

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sthone
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Re: Etxruder and nozzle sharing

Post by sthone » Sat Jul 21, 2018 4:57 pm

All of the original MG files can be found on their GitHub Page
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Vandal968
Posts: 212
Joined: Mon Jul 13, 2015 4:30 am

Re: Etxruder and nozzle sharing

Post by Vandal968 » Sun Jul 22, 2018 12:32 am

I bought the cleaning filament, but never had a good experience with it. Like I said PLA to PETG is effortless. The reverse can be tricky. What I do now is when unloading a PLA color, I set temp to 88C AFTER printing (so the whole hot-end is heat-soaked), then retract. Invariably it comes out with a small ring of burnt plastic and I haven't had a clog in months. When I tried to cold pull from cold, the filament would always stretch and break and not actually remove anything, even at slightly higher temps. The cold pull works MUCH better after printing.

cheers,
c

airscapes
Posts: 219
Joined: Wed Jan 31, 2018 11:36 pm

Re: Etxruder and nozzle sharing

Post by airscapes » Sun Jul 22, 2018 2:59 am

If that is working for you then you are good to go! I made a dial for the tension screw so I can loosen it up to use the cleaner then put it back where it was without guessing. You have to set your feed rate really slow on the manual extrude and only do a few mm at a time with the cleaning filament as it is so soft and not consistent in diameter .. also helps to push it in when extruding.. Then run a couple hundred mm of the new filament before you start a print..

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