Partial blocks with wood pla filament

I seem to be getting regular partial nozzle blocks using the wood PLA filament. The first few items I printed with it were absolutely fine, but I’m currently doing a run of multiple parts and have had a couple of blockages. Now, even after trying to clean the nozzle as best as I can, the parts start fine, but by the end it looks like the nozzle is partially blocked and under extruding quite a lot. They’re not massive parts, only about a 5 hour print.

After the first bigger block, I switched to a new nozzle, so there’s no different type of filament that could be causing issues.

Is this a known problem with the wood filament? Is it worth trying a cleaning filament? I’ve never felt the need for one before now.

Wood filament is highly abrasive. So a lot of problems are solved by using a hardened nozzle. But that’s not usually a clogging issue. It does tend to clog more than normal filament.
You might want to try increasing temperature.
Also a lot of people like to use a .6mm nozzle but still with settings for .4mm. Might have to play with flow to get results you need.

-S

I did just try one with an extra 5 degrees nozzle temp. That one blocked completely!

I have just got some new nozzles, including some 0.6mm ones to try.When you say use a 0.6 but with 0.4mm settings, do you mean literally just change the nozzle and nothing else, or tell cura it’s got a 0.6mm nozzle, but only print with a 0.4mm line width?

Try lowering temp? I’ve heard of some materials getting too hot and basically burning and that causing clogging.

Just change the nozzle. No change to the settings. Print same as you would with a .4. The idea is that the wood filaments don’t flow quite as freely and having the slightly larger nozzle makes up for that.

(BTW, I haven’t done it personally, but I think it’s been discussed on this forum a few times. Probably a year or two ago. Try a search)

-S

One thing I forgot to mention.
Have you tried drying the filament?
Wood filament can be especially susceptible to absorbing moisture.

-S

I haven’t, no. But I’m fairly sure I have no other signs of moisture - no popping, blobs or anything. It prints fine, just the line width gets thinner.

But, I am now thinking it might just be that the nozzle has worn out already (especially if the wood filament is that harsh). I had to pause the wood pieces to print a couple of things with normal pla, so I put a new nozzle in, and the first print going back to the wood is looking ok again. Also, I read somewhere that when extruding the filament (when loading), if it curls up coming out the nozzle (which mine was after trying to clean it) then that’s a sign of a worn nozzle.

Part on the left was an early print. The middle, the last complete print it managed, which was after doing about 15 of these. On the right, with a new nozzle again.

The few tiny gaps I can live with, so I think I’ll see how long this nozzle lasts (I have 50 of these to print!) and then try the 0.6mm if it wears out quickly again.