Word of disclaimer-- I’m coming from the world of using Makerbot 2/2x’s which, in my experience, worked absolutely great. I’ve consistently had 90-95% success rate on prints large & small for the last 2+ years.
Now-- I’m learning the world of Cura and I’ve gotten 1 successful print on 10+ attempts these past 2 weeks. Nearly every print starts well-- first layers look good etc… but after 2 hours or so I’m getting nozzle clogs. I’m printing Lulzbot white 3mm PLA at 205C with layer of .12mm and have minimized retraction to 1.5mm @ 25mm/s speed with minimum move of 4mm after thinking retraction was relentless and eventually pulling too much heated filament upwards. I’ve measured the filament at 2.94mm with .35 nozzle at 30mm/s print speeds. Something is happening after 90 minutes where extrusion is slowing down and I seem to notice that things are going badly in the infill first-- as though the infill extrusion width is getting thinner. There are no visible obstacles to the filament & the spool seems to be unrolling fine. Any suggestions would be welcomed. It’s infuriating to have prints looking great for the first 6-10mm and then failing. I am getting the ground notch in the filament when this happens and have to clean the drive bolt each time. Images attached.
Thanks-
You might try a print with your retraction speed REALLY slowed down. For parts with lots of retractions, (or even those without, lately) on my TAZ 5 I have my retraction speed set to 450 mm/minute, or about 8 mm/second. Surprisingly, it doesn’t add much time to the print. Going that slow should definitely tell you if retraction is the problem.
The “airy” upper layers look like under extrusion. Try tightening the thumbscrews on the idler. Could be a bit of heat creep causing the filament to stick, which would result in the under extrusion.
Also try tilting the little blower by 1-2mm so air hits the lower heatfin. This should help keep the break cooler… and keep the filament from swelling in the break as it turns molten.
Lastly pull the PLA out and dip the tip of the filament into some olive oil. Folks call this “seasoning the hotend”. The premise is the oil should help lubricate the hotend walls and pass the PLA better.
If you’ll be printing a lot of PLA, you may want to look into the mods people have done to reduce heat creep. There are a few fan duct mods which allow better cooling… Search TAZ on Thingiverse.
Thanks- I will try these suggestions. I am trying another print now with lower retraction. I do believe I needed to tighten the idler a bit after reading a few other posts. I had about 12mm between the washers and have tightened to 7mm.
Here is our new design for a fan duct that will combat heat creap. You can also find this file on thingverse.com, just search Dual Duct Halo.
Also on this forum search Dual Duct Halo, I’ve posted some guidelines that I had to learn the hard way, Ahh another 17 Hr print halted do to heat creap. Anyway, not trying to be a comedian I just know how frustrating it is when it goes wrong at 20 hrs deep.
Happy printing,
Open Edge Design
Wear do you think the interfearence is between the duct and hot end?
We plan on upgrading our Taz 4, just not sure how soon.
Any information would be helpful regarding fit and function.
Thanks
The Hexagon hotend dimensions are completely different on the hot end barrel, heater block and nozzle and the positioning of the required stock bore cooling fan for starters.
Thanks thats good to know. As soon as I upgrade the hot end I will redesign this to fit the all metal hot end. Probably do away with the top portion that cools the fins.
It’s not just the dimensions… It’s that the all-metal hotend require cooling on the heatsink at all times. Otherwise the heat will creep up the hotend, causing the filament to melt and clogging the barrel. With the single variable fan, there could be times when the fan isn’t moving enough air across the fins. For example with ABS, most people use little to no cooling from the fan.
