Problems sticking to the build plate edges  

RE: Problems sticking to the build plate edges

Posted by: @aotrs-commander

We have recently just replaced our venerabkle Replicator (about 2700 hours of print time) with a an i3 Mk3S, with the sprng steel PEI plates.

I am using Simplfy3D as the primary slicer, simply because I have over 300 models (CAD modelling for wargames minaitures is my job) and thus having to redo all the supports would be a massive time-sink (and simply using automated supports is WAY too much and increases the print time - inportant to keep down for my customers).

We have solved some problems, but I seem to be having a re-occurring one. The printer does NOT seem to want to stick to the further edges of the build area. With the Replicator, we were used to scattering the models around the build plate so no one area got printed on too much. I tried that with a load of models in the past week, but in particular, I have noticed that the rear right and rear left of the build plate seem to be especially prone to coming loose. Running the centre stills gives us some issues, but does not seem to be as many,

 

I have been cleaning the build plate (after nearly every print, and always as a troublsom one) with the alcohol provided, and we have used at least one wipe with the acetane. I'd be tempted to do it again, but looking at it yesterday night, you're not supposed to do that very often.

 

We're using standard PTA, running at 215ºC.

 

(Okay, it might possibly be slightly sub-standard to what I usually use, but we're using the last of the couldn't-get-our-usual-stuff reel and I have not made significant use of the Prusa reel yet, though, which might be a possible difference, I guess.)

 

The printer has been up and running, incidently, for about eight days, and has been in almost constant use (including one over night) for probably the last four or five (I'm catching up on long-delayed work). (It's probably had probably over 80 hours print time already, from a rough estimation.)

 

Can anyone suggest a possible culprit, or, come to that, whether it significantly matters if I use the centre of the build plate more often (and especially for troublesome prints)?

Hello and welcome to the Prusaforum!

So generally I would clean the printing plate with a degreasing washing-up liquid and lots of water and then wipe it dry with a lint-free cloth. If necessary wipe it with IPA (99.9%).
The differences in adhesion can have different causes.
1.) The printing bed is not flat
2) not levelled or axes not parallel to the printing bed
3) no even printing bed heating (cooler at the edges)

I would check these points and increase the printing bed temperature by 10 degrees.

RE: Problems sticking to the build plate edges

I have been cleaning it with the 99.9% IPA every time, and the once with the Acetone.

Will look into turning the bed heat up - I am, while printing, conducting further tests - I printed one model that failed more than once (and at least onve part-way into the print too) towards the edge in the centre; printed. A print of a different tank towards the edge seemed fine, but just failed about 40% of the way through at the 4.5mm z-height, which is not something I've seen it do before. I am trying that one again dead-centre, and if that does make it through, it would at this point, seem to confirm that there is something off; upping the bed heat will be the next thing I try after that.

RE: Problems sticking to the build plate edges

I'll make yet another call-out for the Layerneer Bed Weld.

I've found that it really helps in cases where PLA just refuses to stick no matter what you do.  It really helps with things like small footprint prints and the first layer of small supports.  It's not an alternative to keeping the build plate clean, but it gives you the extra edge when you need it.

RE: Problems sticking to the build plate edges

• A dirty PEI print surface. Even if you don't think this is the cause, it's always a good idea to make sure your PEI surface is clean before trying any other fixes. If it's a smooth PEI sheet, take it to the kitchen sink and give it a good dunk with Dawn (original formula, no vinegar or hand softener variants) dishwashing soap or your local equivalent (e.g. Fairy in UK). Use a clean paper towel to clean it off, and another to dry it. Avoid using any sponge or cloth that has been in contact with grease. Above all else, avoid touching the PEI print surface. Once it's good and clean, you should be able to use 91%+ isopropyl alcohol between prints, 100% acetone when that fails , and another dunk when acetone fails. Worst-case, use a 3M 7445 ScotchBrite pad or equivalent on smooth PEI to give it a very light buff, but only infrequently. If you've got a textured powder-coated PEI print surface, the official instructions are to use 91%+ isopropyl alcohol on it only. Rumors persist that some tribes deep in the jungle have had good luck getting started with these sheets by giving them a wipe with 100% acetone and a dunk with Dawn. Either way, there's no real warranty on these sheets. YMMV.
• If you have not already done so, try using Jeff Jordan's "Life Adjust" procedure for calibrating your Live-Z setting. It is much easier to use and understand than the on-board routine and much easier to make mid-print adjustments accurately with. In general, start high (less negative) and work lower (more negative) in large increments (e.g. 0.1mm) until the filament starts to stick on its own. When you've got your Live-Z setting adjusted properly, you should be able to gently rub the extruded lines on the PEI surface without dislodging them.  Then start lowering (more negative) the level until there are no gaps between layers. You should not be able to peel the lines apart after printing, but the top should be regular. 

RE: Problems sticking to the build plate edges

I would guess it's an uneven (not flat) print surface if it's just on the otter edges you are having issues.

Look into this...

https://help.prusa3d.com/en/article/bed-level-correction_2267

RE: Problems sticking to the build plate edges

I attempted to print a model in the problem area with the bed temperature raised to 70ºC.

Notably, it printed without any seeming issue. I think this might suggest being more of a cause than the bed level, given that, after our first problems sticking (which were slicer related), the sticking issues have been some way into the print. It seems a little suspicious, at any rate.

(The room is not exactly warm (I'm sitting in here with it, since it's in the smae room as the main computer, but I've not got the fire on and it is October in the Uk, so perhaps the ambient tempature is taking the edge off after a buit?)

The other, in-depth solutions will wait for another day and letting my Dad, who is the more technical engineer (I'm only  CAD engineer, he's the one that built the printer and such) have a look at them.

RE: Problems sticking to the build plate edges

Give some thought to how you're removing prints. Are you by any chance flexing the bed by grabbing it in the problem areas? I find adhesion problems tend to show up along the edges that I use the flex the sheet to remove parts. That's always a good hint that it's time for a quick bath with Dawn under the kitchen sink.

RE: Problems sticking to the build plate edges

@aotrs-commander

I originally had the printer in the garage but once the temperature started to drop it was nae use, Had to move indoors. Lucky we heat the whole house and keep it warm all day as we found that, in years gone by, to be the most economical way. No real sticking problems since that.

As to the other comments. I only clean the sheets with Fairy and HOT water. I have my own sponge for cleaning! once cleaned, rinse off with HOT water. Very little remains to dry off.  And I do that with both the plain sheet and the textured sheet. Have had no sticking problems with either. 

RE: Problems sticking to the build plate edges

Hi there,

on top of re-iterating what bob wrote about clean bed and good live-z, do you do 3x3 or 7x7 mesh bed levelling?

You probably want to switch to the latter, this helps compensating for smaller uneveness (is this a real word?) of the sheet.

Cheers

Hansjoerg

RE: Problems sticking to the build plate edges

I have been cleaning the build plate (after nearly every print, and always as a troublsom one) with the alcohol provided

Alcohol does a superb job of moving oil around, not so good at removing oil from surfaces unless you use ounces and a very absorbent large rag. If it is the smooth PEI sheet, they grab PLA very well when clean, no additives needed or recommended. The textured PEI sheets, they don't like PLA as much, but can usually be made to work. But Soap and Hot water, and a good rinse at a sink is the best cleaning method: scrub and dry with fresh paper towels, and place back on the printer and you are ready to go.

Acetone is needed rarely. I use it every few months when the printer is running 24/7 and I see white shadows of old prints on the sheet (the PEI oxidizes). But I often use soap and water to wash off what the acetone lifts up.

RE: Problems sticking to the build plate edges

As a report, Dad cleaned the plate with fairy liquid as suggested, and tentatively, it seems to have stuck in some of the problem areas thus far. Thanks, all.