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4 / 20
Dec 2017

Hi,

The suggestion to cover at least the front panel appears to off improved the print some, still not

perfect but heading in the right direction at least.

would a raft work better then a brim to minimize the warping?

attached is a couple of photo’s comparing the last print with the most recent one, I’ve also recently learnt

that ultimakers ignore most settings from cura, which result in the fan not being activated for the most recent

print (and myself not realizing till half way through)

any further suggestions welcome

James

Woah. That’s pretty severe underextrusion. Try printing at half whatever speed you are printing at. If you were printing at 260C with the oldest type of Ultimaker with the original teflon that came out a few years ago then it’s probably already time to change to UM’s newer “tfm” teflon which can handle ABS temps for a longer time. Both types of teflon eventually (e.g. 500 hours at 230C or 100 hours at 260C - these are rough guesses - extremely rough) get soft and the pressure from the bowden and the print head and spring (if you have a spring) – all these squeeze the teflon into the filament and cause tons of friction. So you might need a new teflon. Or you might just be printing too fast. The .4mm nozzle can only push so much filament through that small nozzle in a given time.

I think that could be the case because you can see the underextrusion appears not only at the bottom. In general if you just cleaned your nozzle it will start without a problem, but if you not cleaned the nozzle problems from the start. Than you know you need a replacement.

Another possibility is that the spring of the extruder is too tight and your filament becomes oval instead of round. The oval dont fit in the bowdentube, you can feel the friction by hand or you can measure it.

Especially the first layer needs a very slow printing speed.for good adhesion. I use PAI now for good bed adhesion works better than buildtak. (to bay as a spare part for reprap printers)

Hi,

Here is today’s attempt to get a successful print this time using uni’s ultimaker 3(the 2+'s

where either being used or awaiting maintenance), it got most of the way through

before for some reason no longer sticking and becoming the stringy mess at the

top of the picture(it broke in half getting it off the build plate)

Here’s the settings I used:

print speed: 50mm/s

wall speed: 34mm/s

top/bottom speed: 25mm/s

support speed: 26mm/s

travel speed: 250mm/s

initial layer speed: 20mm/s

skirt/brim speed: 20mm/s

print acceleration: 4000mm/s

travel acceleration: 5000mm/s

print jerk: 20mm/s

travel jerk: 20mm/s

fan speed: 25% or 30%(can’t recall which I manually dialed in)

minimum layer time: 7s

minimum speed: 7mm/s

I also enabled the draft shield in addition to covering the front panel

I’m assuming I’ve made some basic mistake, if someone could gently

point it out to me that would be brilliant, also would it make any difference

if I made it 100% infill?

any help is appreciated

James

The fans on the UM3 have rpm control or something weird. 30% and even 10% on the UM3 is the exact same speed as 100%. Only when you get below 10% does it start to slow down. I would do 3% fan. Or even lower. Start with 3%. It broke half way most likely due to too much fan.

So you were getting underextrusion near the end. Not sure why. Were you using cura recommended ABS print temperature? I recommend sticking to cura recommendations for UM3 as they tuned the ABS reasonably well.

Did you cover the front and/or the top of the printer? It really helps a lot.

The fans alone might explain both issues - not sure - underextrusion towards top as it is farther from the print bed and bad bonding.

I think I already asked this but can you get by with PLA? PLA is soooo much easier to deal with. PLA will be stronger, easier to print - the only down side of PLA versus ABS is that PLA can’t handle temperatures above 50C. That’s hot enough to kill a human but is still a common temperature for a car sitting in the hot sun in the summer. So if this is something that needs to be in boiling water or is used in an automobile then definitely don’t use PLA.

Unfortunately I’m really not sure what is causing your underextrusion at the top. Maybe a filament tangle? Check to see if the filament on the rear spool is all tangled or caught on something maybe?

Another thought - 50mm/sec is a bit fast if you are doing .2mm layer height. 0.1mm layer height at 50 is fine but if you are doing .2mm and 50mm/sec I suspect you should try lowering that to maybe 35mm/sec. If you are watching it print and see that characteristic holes-in-the-side of the print as you see in the upper area of the print then just go to TUNE and lower the speed to say 50%.