Having an awful time with first layer where supports go.  

RE: Having an awful time with first layer where supports go.

Update....  I tried cleaning and purging the nozzle an hotend ( heated up to 260 and wiggled the acupuncture needle then refilled with the filament.  No change

Recalibrated z no change

Recalibrated first layer offset on PEI and textured steel sheet no change

Tried the textured steel sheet no change

flipped and cleaned the PEI sheet no change.

Now it will do the first bit of the base for supports ok then just globs up on the nozzle and hotend.  This seems worse in the middle of the bed.

Hotter or cooler temps does not appear to make a difference.

I’m putting this aside for now and will come at it tomorrow or Tuesday.

The PLA is in a filament dryer set at 50 deg till I get up tomorrow.....

RE: Having an awful time with first layer where supports go.

try cleaning your sheet with dawn platinum and a dish sponge scrubber and then drying.   This usually does the trick.   can you print a 75mm 1 layer high square and post the results?  I'm curious if your z is a touch too high.  But I'd definitely try the cleaning first.

RE: Having an awful time with first layer where supports go.

I have slept on this and this seems to be happening worse in the center of any sheet I use.  I used both sides of the PEI and the powder coated steel sheet with the same issues.

I swapped in some prusament PLA that came with the printer, same thing.  

Recalibrated z a few times even to the point of a crazy thin first layer with similar results.

I have tried live adjust on the z with only slight improvement

The bolts holding the extruder carriage were a bit loose so I gently tightened them.  The double upper bearing implementation is in need of a re-design as either it’s too loose or it’s eating bearings and rods.

I’m just doing a full xyz calibration.

Next would be swapping the extruder nozzle.  Good thing I ordered extra!!

RE: Having an awful time with first layer where supports go.

I would try enabling 7x7 mesh leveling.  Not that you should need it for PLA, but have you tried some glue stick, just a test?   

RE: Having an awful time with first layer where supports go.

I did my first cold pull and repeated a second time which was clear.  This was slightly better now.  I gave the nozzle a good external cleaning.

Also bumping the bed up to 70 degrees seems to help.

I’m going to try cleaning the plate as you previously mentioned.

Just as I’m typing this another fail!!!!

Lots of blobs but just where the first squiggles are for supports!!!

First layer of the actual print is fine!!!!

RE: Having an awful time with first layer where supports go.

I shouldn't have to have your bed up to 70 for PLA.  

So after cleaning I would recommend printing one of these squares with with your current zOffset

https://forum.prusa3d.com/forum/original-prusa-i3-mk3s-mk3-assembly-and-first-prints-troubleshooting/life-adjust-z-my-way/

It should peel up from the plate as one piece.  Take a picture of it before you peel it up and post it here also.

I wonder if maybe you're slightly too close now on your Z and the nozzle is dragging those support extrusions.

RE: Having an awful time with first layer where supports go.

I agree with @ssill2, I usually see this when the nozzle is too low. 

RE: Having an awful time with first layer where supports go.

I tried raising the nozzle during the initial swipe and path around the object being printed.  That just lead to stringing and the filament not adhering....

Thanks for all the ideas above I’ll start working through them one by one.

Im also thinking of hitting the PEI sheet with acetone.

I have 12.5 days of printing on this machine so far as per the stats.

RE: Having an awful time with first layer where supports go.

before you do anything as harsh as acetone do try the dawn platinum and scrub.  you shouldn't need anything on the plate to print with PLA.

RE: Having an awful time with first layer where supports go.

Dude!  Saved it!!!!

Dawn and a little scrub with 800 grit sandpaper got me 95% there.  A few tweaks and I got to 98%!!!

so my theory would be that prolonged heat “glazes” the top which needs to be cleaned off???

I’m feeling brave enough to try some TPU for a quad copter project I have on the go....

RE: Having an awful time with first layer where supports go.

This was what it looked like this morning.

I will likely try backing off the z a tick or two....

RE: Having an awful time with first layer where supports go.

Nice.  I don't think you need the sandpaper, just a standard dish sponge with the scrubber on it works fine for me.  you probably reduced the life of that side of the sheet lol.  I keep some 99% IPA just for the texture sheet.

for Tpu I would suggest at minimum a layer of glue stick.  What brand of tpu.  Not all TPUs are created equal and require a good deal of care to print.  I will say the first 4 times I tried to print with it, I ended up having to disassemble the extruder to untangle it!  The key is SLOW.  like 10-15mm/sec, and loosen the idler screw a bit. 

RE: Having an awful time with first layer where supports go.

I have some Sainsmart in my collection.

Good to know about the speeds and feeds for TPU.  I have nozzle cleaning filament on the way.  I might wait until that comes just to be sure.

I’ll try that calibration cube tonight and post the results.

RE: Having an awful time with first layer where supports go.

I regularly use sainsmart pastel tpu, I could give you a profile with the xyz cube to try.

RE: Having an awful time with first layer where supports go.

@ssill2

That would be awesome!!

I'm only a month in to this 3D printing thing and the learning curve is still steep.

RE: Having an awful time with first layer where supports go.

@rob-12

Here's a .3mf for sainsmart tpu with the xzy cube in it.  Give that a try.

I would HIGHLY recommend creating steel sheet profiles as described here

https://help.prusa3d.com/en/article/steel-sheet-profiles_1955/

I find that TPU, PETG and PLA all need different zOffsets for the same sheet.  And sometimes I have to even adjust between different PETGs, etc

So I have the following profiles:(the names can only be very short strings so below it's <name>: description

Spla:  Smooth sheet for pla

Spetg: Smooth sheet for petg

Stpu: Smooth sheet for tpu

Tpetg: Textured sheet for petg

Ttpu: Textured sheet for tpu

Once you've defined a profile or two, you'll be able to change between the sheets from the main menu.  You'll need to run a first layer for each profile, and then it will remember your zOffset for that sheet profile.

RE: Having an awful time with first layer where supports go.

@rob-12

Yes, I only started in November and as I said the first few times I tried to print with even 95A polyflex resulted in abysmal failure.  it's not too bad once you get the hang of it, but every one you try will be have differently.  Ninjaflex for instance is 85A, so much softer than the polyflex or sainsmart.   I think I can print the sainsmart at maybe 20mm/sec but certainly not the ninjaflex.  just listen for clicks when your printing.  if you start hearing that, STOP the print.  otherwise you'll be opening the extruder and untangling things.  it will wrap around the extruder gear if you let it.  I have some working profiles for ninjaflex too if you happen to get any of that.  Poly flex works pretty nicely as well.  Those are the only ones I've tried.

RE: Having an awful time with first layer where supports go.

And did I mention setting up steel sheet profiles? 🙂   

RE: Having an awful time with first layer where supports go.

Dawn and a little scrub with 800 grit sandpaper got me 95% there.

It's a pity you used sandpaper.

For future reference, it's better to wash with detergent and plenty of HOT water two or three times over if needed.  You have probably shortened the life of that plate by scraping it but on the other hand you hve got it back into useable condition.

Cheerio,