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Ultimaker 2+ Failing on First Layer

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Hello there,

I work at a school and we recently replaced our 1.75mm student run printers with two Ultimaker 2+. In the week or so we have had them we have done fairly extensive testing on our Cura profiles and just trying to get successful prints out of them so we know how to teach the students how to use them.

Unfortunately, in our short time of testing so far, almost every print we send is failing in the first few layers. It fails in several ways, usually because the print does not adhere to the bed and collides with the extruder as it passes back over that area. We are not sure if this is a leveling issue or a bed adherence issue or an extrusion issue, so any help would be appreciated.

So far we have tried blue tape on the platform, lowering the initial layer print speed, printing with skirts and brims, and even changing the extruder temperature to see if it was under extruding. So far none of this has seemed to make a difference. Any help would be appreciated.

Thanks

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Its difficult to troubleshoot without more specifics.

You did not say what material you are trying to print with.  I suggest starting with PLA.  Once you have printing going well with PLA then you can move on to others.

With PLA, I usually print directly on the glass, with the bed heated at 60c.  Painters tape is not going to help you much (if any) here.  Its just going to give you a rough bottom layer.  This should be enough to stick most prints.  I typically have to let the built plate cool in the freezer before I can pull the part off.

If you need extra adhesion (sometimes with really tiny parts its needed) then use a glue stick.  Heat the bed up to ~40-50c and apply the glue stick.  Be careful though, this can make the part stick too well.  Only use this if the part will not stick to the glass otherwise (and that should be a pretty rare occurrence)

You should also make sure that the bed is the correct height (and level).  Run through the bed adjustment process on the UM2+ making sure that when you slide the calibration card under the nozzle that you feel just a little bit of friction.  Too much and the printer will try and squish the filament into the bed, too little and it won't stick to the bed at all.

By far the most important thing for adhesion is DO NOT TOUCH THE BED.  I cannot stress this enough.  No one told me this when I got my first printer, and I could never get a print to stick and it was driving me crazy.  It turns out that the oils in your hands and fingers will prevent the part from sticking where ever you touch it.  I can touch the bed once, with the tip of my finger, and watch the print stick everywhere except that exact spot.  Isopropyl Alcohol is good to clean the finger print oils off the bed.

I hope this helps you.

Here is a print I did recently. Its printed directly on the glass bed (60c heated bed), without any glue. It was stuck so well that I had to put the glass build plate in the freezer (you can see the ice forming on the build plate!) and even then it wouldn't pop off without a little force.

bed_stick.jpg

Edited by Guest
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Thanks for the reply!

We have been printing with PLA and we had been cleaning the platform between prints to eliminate oils, so unfortunately that is probably not our issue there.

Our school has decided to not use glue sticks as they are afraid that there is greater potential for error when they are student used and not applied to the platform correctly.

Two things I have noticed in the last week though: First thing was that the bed was not heating evenly, the back would get to around 58 where as the front would only reach about 54. Is this common, and is this something that could be effecting the print?

Second, we switched filament brands and have been having much better results. We still haven't decided on which brand we are going to be using with the students so hopefully this will be making things easier from here and help us make that decision.

Again, sorry for my lack of details and appreciate your help! hopefully we keep getting good results with our new filament and we are good to go from here.

Cheers!

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Our school has decided to not use glue sticks as they are afraid that there is greater potential for error when they are student used and not applied to the platform correctly.

That is unfortunate.  The glue sticks are very useful and almost guarantee your print will stick.  There is a reason that the UM2+'s come with a glue stick.  I don't know the age, skill, or background of your students, but I am pretty confident that with about 2 mins worth of explanation, that any ~8 year old could do it (I have a lot of nieces and nephews if you want an outsider to test this theory!).  It doesn't need to be a perfect application (its very forgiving), just try your best to cover the area that you are going to print on (and if you don't touch the bed between prints, you can print half a dozen times on the same glue area).   There are tricks to make it easier (its easier to spread the glue stick on when the bed is heated, for example), but these are not needed.

First thing was that the bed was not heating evenly, the back would get to around 58 where as the front would only reach about 54. Is this common, and is this something that could be effecting the print?

With PLA, a heated bed is unnecessary (though helpful), so I doubt that the a few degrees variance is going to make a difference.  I have not checked but its likely that the heating element is positioned where you are getting the 58c.  It is always going to be hotter nearest the source of heat.

Second, we switched filament brands and have been having much better results. We still haven't decided on which brand we are going to be using with the students so hopefully this will be making things easier from here and help us make that decision.

I use (almost exclusively) MakerGeek filament.  I highly recommend it (its very low cost, about $15 per kilo if you let them select random colors for you).   I have nothing but great prints with this filament.  It prints at a higher temperature than most PLA (210c is what I generally print it at) but it has always given me great results.

Again, sorry for my lack of details and appreciate your help! hopefully we keep getting good results with our new filament and we are good to go from here.

Cheers!

I hope it works out for you! Don't fear the glue stick!

Edited by Guest

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