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Jinja

Help. First layer problems

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Hi

I've had my U2+ now for about four weeks and it's been printing faultlessly over that time.  However the last couple of days I can't seem to get the first few layers down without warping!

I've tried 4 different brands of PLA, heat settings from 60º all the way up to 90º, tried glue stick, reset the heatbed each time and cleaned the glass several times, but nothing seems to work!  It's really frustrating as it doesn't seem anything can fix the problem.  

It's basically lifting, not adhering to the build plate.  The plate is definitely hot, the nozzle distance has been calibrated am at my wits end to be honest.

Any help please :)

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Lets see if i can be of any help till the pros show up ;-)

60°C bed temp should be more than plenty for PLA. More doesn't make it better in my experience. Did you try 50°C?

What are you using to clean your buildplate? Been using window cleaner at first. It apparently left some residue that needed a good wash in the sink to get rid of. Ever since all i am using is isoprop alcohol 70% or higher on a paper towel.

I'm getting mixed results with the standard nozzle height procedure as well. Starting from there, I usually just go ahead and turn the 3 knobs some more during the 1st layer of a test print in order to squish my first layer down even more.

Can you take a picture of your first layer?

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Ohhh @StephanK just beat me to it! ;)

Do you remember when your prints started warping @Jinja?

Are you sure it happens with PLA too, have you also used ABS?

It would be helpful if you could include a photo of what a warped print looks like, and how your first layer looks like.

Have you tried using both sides of your glass plate?

The side with the warning-sticker offers you the best adhesion.

How do you clean your bed?

Looking forward hearing from you!

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Hmn, I think I am going to be devilish and blow away all the comments on first layer bed adhesion and temperature made over the past 2 years or so, including mine!

I always use a brim or a skirt. When I started printing 3 years ago I used Slic3r, which had the option to set a 1st layer temp. and a different temp. for remaining layers. So I would set the 1st layer temp higher.

When I switched to Cura I lost this option and so at first I set the Cura bed temp. to a higher temp. and after the 1st layer I used Repetier Host to turn down the bed temp. The problem was that often I forgot to do this and finally I settled on just setting the Cura bed temp. at 60c.

What I have suffered from for a long time is that as the print would start the first few mm, or indeed cm, of the skirt or brim would not stick so that before the actual model started to print there would be a tail attached to the extruder. This was never a major problem as I always had a game with a long screwdriver chasing the tail and catching it and moving t away from the print area. The only real problem was with an inside and outside brim where the tail would stretch across the model print area.

Recently I spent some time testing nGen and nGenflex and with both materials I noticed that the filament stuck to the bed immediately, i.e. no tail. That was very nice and I thought what a lovely material and left it there.

I do not know why but last week I was thinking about it again and realised, “you idiot there was a difference, with those new materials the bed temp was 75/80, not 60”. So I tried it, with the bed temp pumped up to 75c I ran some PLA and hey presto not a hint of a tail. So for the past week I have been starting 1st layer at 75 and then reducing to 60 once the layer is complete. This coming week I will dial it down to 70 and see…

It is quite possible that this would not do you any favours with something like Marvin but I never print that small. With my printer I will be pretty much down to 60 by the time the 2nd layer has finished.

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I print a lot of large, rectangular models and warpage has been a pain in my past!

My first year, I learned to pay attention to what the building's climate control is doing. I started printing at work about a year ago around this time of year. When the winter came and the humidity dropped and the building's heat kicked on, I had a rough couple weeks. Same in the spring.

I have a pretty good system for PLA now. When I clean my glass, I flush it under hot water under the sink to rinse off all the old glue. I like the break rooms sink, i has a shower-like faucet and I can lean the glass against the sink, let it flow, then flip the glass to the other side and repeat.

I then dry the glass, wipe it off with isopropyl and it is ready to print again. Typically, when I put it in the printer, I heat it up to 30-50c and do a thin layer of glues, then go cross-wise across that with another layer. I learned a little heat makes the glue spread easier.

I always use the elmer's goes on purple/dries clear glue. It helps me to see where the glue is so I know it has good coverage and when I wash it it turns purple when wet so I can see that it is all gone. Not all glue sticks are the same. I have used some other brands, even variations of the elmer's glue sticks and the results have been disappointing.

Sometimes if I am in a hurry, I will use glass cleaner between prints...but use the cheap blue stuff or windex original. I have found low or no ammonia glass cleaner is horrible for this use. I sometimes will spray, wipe the plate and re-spread the glue without applying new glue. For larger prints, I just re-prep the bed.

Be sure to check your first layer height/bed height. I like to see it go on nice and flat for most my prints. I know that if you smash it in, you're gonna end up with a print that is .1-.2mm shorter than you intended, but for most prints that doesn't matter.

Most my models are about 3"x6" rectangular building sections. After starting this regimen between prints, I was able to ditch the brim entirely and my corners don't lift up at all.

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