The past few weeks I tried alot of different settings like:
- disabling retraction between the printing of each object; this had the most influence on the problem of the clogged printhead after 1 object was printed
- setting the fan to 30%. This had influence on the layer buildup
- changing the bed temperature and trying different "layer" thickness of solvable glue (Pritt) on the glassplate
- mounting the printer nozzle very tight to the aluminum heator block, even using a little bit of CPU-heat-conducting-paste between the contact area of the nozzle and block.
All this led to slight improvements, but unfortunately I didn't reach stable results. So I decided to contact two printer vendors with the request to print my project. Depending on these results, I will purchase a new printer for printing these types of abs projects.
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gr5 2,224
Maybe not related but 250C is a little dangerously hot with ABS. If you leave it at 250C in the nozzle too long (maybe 5 minutes) wihtout printing it turns into a gunk that will clog the nozzle. This is the same consistency as gum that someone chewed for a while and then let get down to room temperature.
How old is this UMO? I'm guessing either you put the head together slightly wrong or the teflon part (the white part) has gotten old and is too soft and can expand under inner pressure from the filament. You can test all this by doing a cold pull (google it and restrict searches to ultimaker.com). After the cold pull you can look at the filament shape and should be able to see each piece of the inside of your print head (where nozzle exists, where brass tube is, teflon part, peek part, etc. I'm thinking maybe things aren't flush when screwed together. It's tricky when assembling the head. A photo would help.
What can happen is after the print is over if it cools a bit the filament can expand into a section of the print head that is below 100C and get stuck there so it won't go in or out. I could be completely wrong about this diagnosis. It could be the 250C thing.
I usually print ABS at 245C and set the fan to the minimum (around 30%). It also helps to enclose the printer somewhat to get the air temp at 35C to 40C. But this has nothing to do with clogging.
On work around is of course to remove and re-insert the filament after every print. I know that's not a great solution for you.
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esmeesaglam 0
Thank you for your answer! The points you raised are new. This weekend I will give it a try and post my results. Since I have to disassemble the printhead I will make some pictures.
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