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geert9

Bottom layer not sticking

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Hello guys,

After spending a day trying to figure out what the problem is with my Ultimaker 2 I give up and hope you guys can help me out... For some reason the bottom layer (first printed layer) doesn't stick at all and the head just keeps pulling the filament around. img_20151014_174449.thumb.jpg.6db6dfb4ed32197e663a22700e19502a.jpg

The problem just occurred out of nowhere. A print that worked before now just doesn't work anymore...

I tried:

- Cleaning the nozzle (Athomic method)

- Clean the glass plate

- Recalibrate

- Make sure the stepper motors are locked in place

Anymore things I can try or anybody has the same problem?

Thanks in advance.

Geert

img_20151014_174449.thumb.jpg.6db6dfb4ed32197e663a22700e19502a.jpg

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Yes I am sure we have all had your problem at some stage. In addition to what you have done...

When you say "recalibrate" I assume you mean bed levelling; have you checked the nozzle tip to bed distance too? When it has happened to me it has been one or both of these causing the problem.

Bed temperature; I would be 99% sure that your temp. sensor is measuring the temperature of your bed, not of the glass plate. Have you used an IR temp gun to check the glass temp.?

Also depending on the temp. sensor and its location, if the centre is showing the right temp. it can take another 10-15 mins for the perimeter areas to get up to temp. But if you have printed this model before I suspect this point is not relevant.

Are you using the same filament as before?

Have you done a manual feed beforehand to check that the filament IS flowing OK i.e consistent and not thinner than before?

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Thanks for answering @yellowshark. I think the problem is the filament flow. Although there is some flow it's not the usual amount and also sometimes it's thicker and sometimes thinner with black dots in it, it all depends. Maybe the nozzle has had his best time? Thanks for the help so far.

Edited by Guest

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OK the symptoms you are describing would normally arise from one of..

Inconsistent filament width, so it will get stuck in the feed path, maybe momentarily but consistently.

A problem with the drive mechanism; but if you are not hearing clicking that is unlikely.

Maybe too low a temperature; but you sound too experienced to fall for that one.

A blockage. Now you said you have done an atomic pull but as you are seeing black bits in the flow then I would say you still have filament stuck in the nozzle. Several points here…

Sometimes you can clear a blockage with one atomic pull, sometimes you need several, sometimes you might need 6 7 8.

Filament can get stuck in the nozzle shaft and the atomic pull does not always shift that. I think my nozzle shaft is longer than those fitted to the Ultimaker and I have experienced it several times. The technique I use is to boil a small saucepan of water and submerse the nozzle(removed from the extruder) in the boiling water for two or three minutes. Then taking the nozzle out I poke around with a pin, through the nozzle hole and also from the shaft end with something pointy like a small flat bladed screwdriver. If you hold the nozzle up to the window and look down the shaft you can often see some strands of filament. You may have to do this several times to dislodge the filament.

If you use ABS and PLA and use PLA to atomic pull, then if the stuck filament is ABS you need to push the PLA temp. way beyond your normal temp. so that the ABS melts and dislodges.

As for the filament, if not done so already, it is worth taking readings along the first 1-2 metre length to check they are all sub 3mm

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The feed path and drive seems to be okay since inserting the material and removing it works without me manually helping the feeder/driver... Although when you insert new material and it start coming out I hear the clicking but I'm not sure or this is normal or not. This only happens in the inserting material stage because when it's printing it doesn't click at all.

I did around 20 atomic pulls so I guess that's not working. In posts I saw before it stated that when you do atomic pulls after a few times the removed part should look like a cone but that's not the case. Well not a normal cone. (note: they are not in order but they did came out from darker to white... IMG_20151016_085239.thumb.jpg.eaff6211544d0fdd1b3cd690d215dfb9.jpg

I didn't use different materials in a long time. We have used ABS before but that was like a year ago. Also the problem started occurring without changing the material.

I think I'm going to try the boiling the nozzle solution hopefully that will work.

Just to give you some more info about the printer. He has now done 892 hours of printing, I have no idea though after how many hours I need to replace the nozzle...

Thanks again for taking the time to answer on my post!

IMG_20151016_085239.thumb.jpg.eaff6211544d0fdd1b3cd690d215dfb9.jpg

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What I always use for testing is either my fingertip or the point of a screwdriver to gently move over the first layer.

If you pull it off it is not stuck, if it stays on its place it is good.

How is it with you?

At what speed is your first layer deployed?

Do you use the same gcode or the same model as before?

I am not convinced it is a hot end problem, but I did see something off in your picture:

tips.thumb.png.303a2409056bff15e46145e99bfdac93.png

Red: Left fan, there is a gab and should be closed. You can bent the fan shroud to close the gab. But on the right side it is to closed. Open it up a little bit. (but to closed is better than to open).

Blue: There should be a 2mm gab in between the PTFE part and metal coupler.

Yellow: I am not really sure what the white part is in the bowden tube? There seems to be residue.. but since the PTFE and filament are also white it is hard to tell what it is.

Dunno of any of these have anything to do with first layers not sticking, but it are areas that can be improved.

tips.thumb.png.303a2409056bff15e46145e99bfdac93.png

Edited by Guest

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Hmn, well I have never seen "cones" looking that bad. If the missing 6 pulls cam out after your photo and were white then you have probably cleared it. If they cam before those 14 pulls then I would say you may not have cleared it.

You to have a bit of a mess there. I ask myself if you have been running your PLA too hot - what temps. do you normally use?

Was the photo above of the print bed taken before or after you did the atomic pulls?

What is you first layer speed?

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have you tried manually feeding some filament through the nozzle? does it come through in a spiral or in a strait line?

My solution is the blue painters tape.

I carefully laid about 6 lines of 1.4 in tape and then placed an extra strip for the initial wipe action at the beginning of the print with a slight fold in it (shown in the circle)

Btw random rant at ultimaker please move these clips, throw it away, and make ones that don't cut my thumb when I'm trying to remove them! ;)lol (denoted by the arrow)

5a33129eaaffb_2015-10-1616_06_53.thumb.jpg.38e7c33bea050c1e6b2ac20844db5c16.jpg

5a33129eaaffb_2015-10-1616_06_53.thumb.jpg.38e7c33bea050c1e6b2ac20844db5c16.jpg

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