Mucky rough first layer, and flat prints detaching.
Hi folks.
This is my third attempt to post this - I might have hit the worng button on my phone, and sent a completely blank title first, and then posted into the wrong forum. Some of the guys in the Mini section were very helpful.
This represents a last ditch effort to get it right.
I've had a i3 Mk3 for 2 weeks now, (I'm a novice to 3d printing). I have found that 
when I print on the left side of the bed the prints seem to come out well.
If I want multiple items (these are face mask holders to prevent ear pain) then I put 6 up and use the whole bed. Often these prints fail, usually at the right hand side of the bed.
I am printing with PLA, (Prusament) and the hotend and bed temperatures are 215/60°C.
Speed is 100% and the Z offset is -0.642 as set up following many calibrations because of similar problems in the past. This print is illustrative of the usual problem. The prints on the right, and especially at the back, are noisier than the others as if there's a vertical interference going on, but at the start of each print, the printer is happy with the 9 point calibration every time. (Update, the back right item during this print lifted off the bed from the first layer, and got knocked off its perch completely on the 4th layer, and I had to abandon the print.)
I'm printing on the magnetic metal bed that came with the printer. I cleaned it prior to the print with PureChem Industrial 99% pure Isopropanol on a kitchen paper towel, and then finished off with water and a dry rub with the same kitchen towel. (The bed was not cool when I did this, and some kind soul has pointed out the error of my ways in that respect).
On this run, the skirt came adrift as soon as it was laid down, and I had to remove it. The back left and front left prints successfully laid down both the outlines and the first layers with no problem. After that, when it started to print the outline for the middle left one, that came adrift also, and needed to be removed, and the printing as you can see becomes increasingly rough as it moves right, calming down a little at the rightmost one at the front. The rear one on the right also lost it's outline, lifted from the bed during the first layer, and has been noisy to print because the nozzle is banging into the lumps in the print.
I uploaded the item I'm printing as a "thing", onto Thingiverse.com so if you're interested you can see what I'm printing. It has a huge flat footprint, and really shouldn't be lifting off the bed.
Should I reach for the Pritt glue stick and the hair drier here, or is there something else I should be looking at?
Many thanks,
RE: Mucky rough first layer, and flat prints detaching.
Every filament is different, also it could be a little bad filament, try different filament.
Most important is :
1 Clean bed with dish soap, dry it and use it.
2 First layer should be 100% perfect. See youtube for examples.
3 use 7 point calibration.
A new bed, clean a few times with dish soap, a new bed sticks not as good as a used one.
Some people us a soft scrub sponge(i do not use this).
PLA use the pei bed, the other bed pla sticks not as good, but with better settings i should be possible.
Big flat models or models with small part on bed, use glue stick, a thin layer. Glue stick ,test which one works good, some work not as good,
and here i always clean first with dish soap.
Extra: (normally not needed):
First and second layer 5 or 10 higher temps.
Bed 5 or 10 higher temp.
If needed , print first layer slower.
Depends on what i print, is clean it with dish soap.
Some print i use glue stick, a few times without cleaning.
Also if i work with no glue stick, i use a few times alcohol, then after a few prints i use dish soap again.
If you want to avoid a big ball of filament sticking on the nozzle, keep the model sticking 100%,
and if you start a print, look at the first layer if this is OK(every print), the after the first layer is finished, look if it is sticking ok.
RE: Mucky rough first layer, and flat prints detaching.
I use the pei sheet only at the moment.
Glue stick from china, the yellow one , name deli.
And 3d printing will never be easy, there will always be problems.
RE: Mucky rough first layer, and flat prints detaching.
Thanks guys, I will get a PEI sheet - the metal one came with the printer. 3M make a self-adhesive PEI sheet - would it be OK to glue that to one side of the metal sheet? That way I'd have easy access to both.
I'm currently using the default PLA settings from Prusa - 215/60°. Very useful to get tips about running the bed hotter; I'll give it a try. I suspect that my filament is not sufficiently squished; the top of a single filament is only a little indented. But the result when I print the little 1-layer squares in calibration stick together well.
There's so much to learn - I'm spending hours on Youtube! What did I do before lockdown??
Cheers and many thanks for your advice.
Pad
RE: Mucky rough first layer, and flat prints detaching.
Just realised that the magnetic metal sheet is powder-coated PEI!
I ordered some red filament from the net (PLA+ whatever that is) and have set the first layer to run at 225/65, returning to the default for the subsequent layers. This new stuff seems very well stuck to the bed, but there's a lot more stringiness.
"there will always be problems (with 3d printing)" - Probably the most accurate understatement in the world!
Many thanks,
Pad