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Trouble printing brown ABS; printhead gets clogged after the first object is printed when printing the object multiple times

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My name is Esmee, I am 13 years old and I am trying to print an brown object with ABS on my Ultimaker Original. The problem is that most of the times, after I cleaned the nozzle, the brown abs gets clogged in the nozzle. It doesn't matter if I print one object in one print session or one object several times. This is what happens if I try to print the object 9 times with the option "print at a time".


The first object gets printed after that it continues to print but the ABS clogges the nozzle causing that no ABS comes out of the nozzle anymore.


  • So far:
  • I tried two brand new nozzles to make sure the ABS doesn't mix up with the TPU I am using for another project.
  • tried a lot off differtent printer settings
  • closing the printer housing with carboard plates (left/right/front closed // top open)
  • cleaned the nozzle, a lot!, very thoroughly with aceton and as less as possible in a mechanical way to prevent damaging the contact surface.
  • tried finding another supplier/brand of this brown ABS but didn't succeed


Does anyone have experience in printing this brown ABS in a good way or does somebody know how to get this done on my printer?

I use:

software: Cura LulzBot Edition version 21.08

printer: ultimaker orignal plus

brown abs: Makerpoint Mahogany Brown

My settings are as follows:


QUALITY Layer Height (mm) 0,1Shell thickness (mm) 0,8Enable retraction checkmark ONminimum travel (mm) 1,5combing type allminimal extrusion before retracting (mm) 0,02Z hop when retracting (mm) 0.0FILL Bottom/Top thickness (mm) 0.6Fill Density (%) 20solid infill top checkmark ONsolid infill bottom checkmark ONinfill overlap (%) 15SPEED AND TEMPERATURE Print speed (mm/s) 50Printing temperature © 250Bed temperature © 110SUPPORT Support type NonePlatform adhesion type BrimFILAMENT Diameter (mm) 2.85Flow (%) 107.0MACHINE Nozzle size (mm) 0.4RETRACTION Speed (mm/s) 40Distance (mm) 4.5QUALITY Initial layer thickness (mm) 0.3Initial layer line width (%) 100Cut off object bottom (mm) 0.0Dual extrusion overlap (mm) 0.15SPEED   Travel speed (mm/s) 150Bottom layer speed (mm/s) 20Infill speed (mm/s) 80Top/bottom speed (mm/s) 15Outer shell speed (mm/s) 30Inner shell speed (mm/s) 60COOL Minimal layer time (sec) 5Enable cooling fan checkmark ONFan full on at height (mm) 0.5Fan speed min (%) 50Fan speed max (%) 50Minimum speed (mm/s) 20Cool head lift checkmark OFF



Edited by Guest

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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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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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I don't know lulzbot very well but I know they are open source. They probably also have an active community just like this Ultimaker community. On a UM2 if turning off retraction reduces clogging then the problem is usually the "third fan" on the back of the printer that keeps the upper parts of the hot end cool.

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