Adhesion Nightmares

I have a new TAZ 5 and am having no end of difficulty getting a descent print. After the initial Rockapus went well, bed adhesion has been terrible. Here are some observations:

  • My first ABS prints stuck so hard they were extremely difficult to get off.
  • Now, nothing seems to stick at all.
  • I have tried cleaning with IPA.
  • I have tried painters tape and glue stick.
  • Failures occur with both ABS and PLA, with Brim and without.
  • I have tweaked the Z-stop, checking for the double-paper
  • My prints start well, but reach a certain height and then start sliding around.
  • Sometimes they stick to the extruder, which due to printing disasters, now has filament melted on the outside.
  • I tried a new, clean print head. No help.
  • I have not yet changed the one-month old PEI sheet, but that is next on the list of things to try.

And I wonder if part of the problem is the print sticking to the extruder? Too much drag at the top of the print?

The only time I have seen double-paper is for the dual extruder. Should be one paper thickness or about 0.1 MM.

ABS and PLA do not like to stick to each other, so you need to remove one before using the other. ABS = Acetone, PLA = Light sanding off.

Sounds like bed was too close at first and is too far off now.

The Quick Start installation instructions say to use a once folded piece of paper and that there should be slight resistance. But I will get it closer and see if it helps.

Print a calibration cube… even if only 1-2mm. Post the pic of the top and bottom.

Out of the box, the TAZ usually overextrudes… but not to the point that its dragging across your print. Calibrate your esteps or lower the flow rate in your slicer.

Sanding with a fine grit can help the PEI adhere to ABS/PLA better. Frankly, ooze should stick pretty well to the PEI. Try a bed temp of 110C for ABS if you’re not doing so already.

You didn’t by any chance get some sort of lubricant on your PEI, did you (WD40 or something)?

I have brought the bed closer, folded sheet of paper takes more force to move. Seems better now, for PLA at least. Haven’t tried other filaments. I have also reduced the flow, to lessen oozing and stringiness, which may also be helping.

No, there is no lubricant on the bed, except maybe some unintentional skin oils. But I’ve cleaned it with IPA.

I asked because a friend decided to lbe his threaded rods with something like WD40 or FluidFilm, then had real problems with adhesion. (I guess overspray is a bitch).

Try cleaning the bed with a Mr. Clean Magic Eraser sponge… its has a slight grit which removes oils and any leftover filament.

Where are you testing the nozzle height? Make sure the nozzle is at extrusion temp (this compensates for thermal expansion of the brass nozzle), and check in the middle of the bed.

I’d also check that the bed is level… print 4 20x20x2mm calibration cubes: Front, Back, Left, Right. Look at the pattern created by the extrusion on the bottom of the print. The four calibration cubes should be uniform from a visual perspective. The individual rows of extrusion should look oblong, squishing together to forma flatter solid surface. Not round as if directly out of the nozzle. Sorry, its hard to describe.

I’m guessing green ScotchBrite pads are way too aggressive?

Give them a try… :slight_smile:

I have found my experience isn’t as positive as other with PEI. My ooze has never just “stuck”. I think my PEI just isn’t as sticky as others. However I’ve gotten it to work with perfect part adhesion every time.

I’m going to save you a lot of headache and weeks (months?) of misery.

Go buy 2000 grit sand paper. Sand the living crap out of your PEI bed. Put some elbow grease in it. You won’t hurt the bed because the sand paper will lose its coarseness before you ever do. Honestly I do this every few prints.

What I’ve found is that when a part stick overly well (which is what happened to you) you lose a significant amount of stick. Nothing will bring it back but a good amount of sanding. (I believe it’s due to plastic getting overly smashed into the PEI pores)

I know this from personal experience. I go over over stick on my long 15 hour prints. The parts I print need to have perfect bed adhesion and honestly aren’t easy parts to print/stick. Thus I over stick them. Thus I lose stickiness on my bed more than others. Thus I sand more than others.

Also I’ve found anything less than 90 percent IPA isn’t worth your time. The diluted stuff doesn’t cut through the leftover residue.

Sand then clean with IPA.

Also the thickness of 1 sheet of paper still seems to tall. I do everything by visual sight. I print a line and then adjust the Z height. I keep. Lowering it until I see tracking? Treading? (the wagon wheel effect) and then I slowly raise the Z nut until just barely where I don’t see it. Make sure you’re doing this at the center of your plate.

*the problem is, is that no one else on these forums ever seemed to have sand their PEI. Which is absolutely baffling to me.

So no one was able to explain to me HEAVY sanding.

Everyone would say “no don’t sand, I never have needed it” or “light sanding” or even the “mr clean magic erasers”. Don’t get me wrong I use a mr clean magic eraser on rare occasion when I know I don’t need to do a full sand. But when you’ve lost the stickiness, the magic eraser just won’t cut it

Yes, and while I greatly appreciate all the advice, I find much of it contradictory. Some people swear by sanding, others by cleaning, others by tape, others by glue. Don’t have time to try everything.

As for me, things are going better, but I’m not sure why. Raising the bed closer to the nozzle helped it stick. Haven’t had any spaghetti for awhile, but last lights PLA stuck so hard I thought it would break or I’d damage the sheet. Seems to bounce between extremes.

Just make sure you’re getting advice on using PEI with the type of filament you’re printing.

Blue tape - should only be necessary when printing semi-flex filaments like ninjaflex.
PVA Glue - good for nylon… but don’t quote me on that
Cleaning… IPA is good sometimes, but I don’t find it very effective
Sanding - should always help because it removes the leftover filament… but sanding removes material, thus expect to replace.
Magic Eraser - as far as I can tell it doesn’t remove PEI, but has enough grit to remove contaminants (oil, fillers) and over stuck filament.

Check the surface temp of with a IR thermometer… While the thermister may report the right temp, there could be an offset on the surface. I’ve read people going up to 115C for ABS… But extruding at 245C, the ABS should stick at 100C.

As for heavy sanding… were you having these problems a few months ago? So is the replacement showing issues too? It might be something else with the electronics (RAMBO-MOSFETS, or PSU). Spot check the temp. Call Lulzbot before your warranty runs out. Try heating the PEI externally as an experiment… try a hairdryer for a minute or two after reaching temp, then print a calibration cube.

All the information is contradictory and confusing. Believe me I know because I was in the same position as you months ago. I did spend months trying everything.

Simple and effective solution. Sand.

I found the magic eraser only helped remove leftover filament if it was NOT truly stuck on. But the sanding will get everything off.

Sure sanding will remove material, but we are talking about 2000 grit. I’m removing microns at most. I’ve been sanding my sheet 1-3 times a week for months with no noticeable change. I estimate at least a year of sanding before I would need to replace.

1 new PEI sheet a year… Or dozens of failed prints. I believe the PEI sheet replacement to be a cheaper, and more effective replacement over $$$ of wasted filament and print time.

So I’ve now come full circle. I am back to where I started, ABS sticking to the bed. I tore the PEI sheet getting it off.

One more variable to throw into the mix – nozzle gap. I think some plastics need to be closer to stick, PLA. Others need to be farther to not stick too much, ABS.

Yes. Initial nozzle height is definitely a factor. Get it to two sheets initially, then use Z-Offset in slicing software can help with tweaking this for the material or bottom layer smoothness.

The nozzle height thing has me wondering: We’ve got the Mini for the school I’ve been working with dialed in pretty well for printing with PLA. We’re about to finish with that, and start in on a few rolls of ESun HIPS they were given. I know we may need to fine tune the temperatures in the HIPS quickprint profiles a bit. Are we likely going to need to adjust Z-offset as well? I bumped it up by 0.1mm since the PLA prints were sticking too hard. Just wondering about the relative “stickiness” of PLA vs HIPS.

If gap height is confirmed as important, perhaps LulzBot could add Z-offset to default profiles.