Sudden Problems With my Printer

[CFLBob]

I have a Creality Ender 3V2 that I've been learning the ins and outs of printing on, and in the last few days, it has developed a problem I've never seen before.

No filament sticks to the bed.

In the last few days, I went to make a little tool to hold sand paper onto a crankshaft I'm making. Think of a popsicle stick with a thicker handle at the back. The stick portion is thin, 1/8", and the back handle is 1/2" thick. The whole thing is 3/8" wide. I came up with a design and printed a prototype with a minor issue. One corner of the first layer didn't stick to the bed well, and I had not used a glue stick. Later in the print, the thin end of the stick lifted into the air and in a test to see if I could put a spot of glue there and push it down, the whole thing came off the table. I aborted the print but it's still usable.

In an effort to get another couple of sticks for different grade sandpapers, I used a glue stick, and that always sticks so well it's hard to get things off. In the midst, I tried to print some squares, used to test the bed flatness and they would just stick erratically.

Since that first issue, I've cleaned the bed three or four times and nothing gets the filament out of the extruder to stick to the bed without a glue stick. I've used plain water, soapy water, denatured alcohol and isopropyl alcohol. Just in terms of the pure tendency to stick to the bed, it has gotten worse every time I've cleaned it. I've tried printing designs that I know have worked effortlessly before and every attempt fails.

I've used two different colors of eSUN PLA+
https://smile.amazon.com/gp/product/B01EKEMIIS/ref=ppx_yo_dt_b_asin_title_o05_s00?ie=UTF8&psc=1and a little piece of plain PLA that came with the printer as a sample to get you started. I have a waterproof dry box to store filaments in that aren't being used, and they're all sealed in there between uses. The PLA+ says on the label that heating the bed isn't necessary, but I've experimented with that, and I have things around here I printed without the bed being heated. I've adjusted the extruder temperature from plain PLA up to the somewhat higher temperature the PLA+ wants (210 to 220C) but I've tried it at 190 and 200, too.

Nothing seems to be helping and I'm at a loss for what to do next. I'd appreciate any ideas.



Bob

 

[GreenTwin]

I have a Prusa and experienced the same thing.
I sent them some questions, and they responded.

The bed adhesion is directly related to the initial setting of the head height above the bed.
If the head height drifts off slightly, and the head operates at too high a setting, you will get no adhesion, regardless of any glue or anything else you do.

The head adjustment was a bit confusing, but what I did is go into adjustment mode, where the printer is printing, and you can dial the head up and down during the print.

I noted the reading on the head height and wrote that down.
Then I took a sheet of paper and put it under the print head while it was printing.
I adjusted the head height down until the paper started dragging, noted the reading on the head height, and then raised the head slightly, and again recorded that reading.

My adhesion problem vanished immediately, just as Prusa said it would.
No glue is required on the bed when the head height is adjusted correctly (for my Prusa anyway).

It seems that what is happening is if the head is too high, the liquid filament starts to harden before it contacts the bed, and thus a solidified filament will not adhere to the bed.
The trick is to get the head to apply the filament in a melted state, so that the plastic is still liquid when it contacts the bed surface.

Obviously the bed needs to be cleaned before each use, but I have even gotten good bed adhesion without much bed cleaning just by having the head height set correctly.

Pat J
.

 

[CFLBob]

I have a Prusa and experienced the same thing.
I sent them some questions, and they responded.

The bed adhesion is directly related to the initial setting of the head height above the bed.
If the head height drifts off slightly, and the head operates at too high a setting, you will get no adhesion, regardless of any glue or anything else you do.

The head adjustment was a bit confusing, but what I did is go into adjustment mode, where the printer is printing, and you can dial the head up and down during the print.

I noted the reading on the head height and wrote that down.
Then I took a sheet of paper and put it under the print head while it was printing.
I adjusted the head height down until the paper started dragging, noted the reading on the head height, and then raised the head slightly, and again recorded that reading.

My adhesion problem vanished immediately, just as Prusa said it would.
No glue is required on the bed when the head height is adjusted correctly (for my Prusa anyway).

It seems that what is happening is if the head is too high, the liquid filament starts to harden before it contacts the bed, and thus a solidified filament will not adhere to the bed.
The trick is to get the head to apply the filament in a melted state, so that the plastic is still liquid when it contacts the bed surface.

Obviously the bed needs to be cleaned before each use, but I have even gotten good bed adhesion without much bed cleaning just by having the head height set correctly.

Pat J
.

Mind blown. That might just be it, Pat.

This all started when I re-leveled the bed. To do that, I used a new method that uses a .008 feeler gauge to set the gap between the nozzle and the bed. The YouTube channel I got it from (CHEP here) had the tutorial and I dutifully followed his steps. His printer apparently never had the issue.

I can go back to the .004", sheet of paper method and try that method. (I don't have a .004 feeler gauge).

 

[GreenTwin]

Had I not gone through the exercise myself, I never would have believed it could just be the head height.

I knew something was up though because the printer had excellent bed adhesion for a long time.
Cleaning the bed and using glue on the bed had no apparent effect.

Sometimes the simplest solution is the least obvious (it was for me).

.

 

[giel]

buy a can of 3DLACK and your problems will dissapear no more warping or bad adhesion, just a little puff! on your printbed (make sure it is grease free before applying)
and start printing i had this problem for 2 months tried all kind of things until i bought a can of the stuff. printing every day +/- 1kg and still on my first can now for a year
you can print 2 to 3 times on a sprayed surface. the part will come loose after cooling.
i use window glass sheets just swap them after printing and wait for 15 to 20 min and you hear it crack loose.
print without a brim and first layer at 100% and normal temp (pla hotbed 60⁰c petg 70 to 80⁰c abs 110⁰c) first 3 layers no part cooling fan. enjoy printing!!!!

 

[nealeb]

If you are using a nozzle height of .008", that would explain it. My usual layer height is 0.2mm, which is .008". That means that there is no "squish" on to the bed on the first layer which is essential for it to stick. Otherwise, as already said above, you just lay a bead of plastic on the bed. Go back to the typing paper - I use it for all sorts of things as a disposable .004" feeler gauge!

 

[cwelkie]

Another source for more durable .004/5" feeler gauge material is your favourite (aluminium) beverage container. They are very consistent in thickness.

 

[Rb72]

I have the same printer and was having the same problem even after leveling the bed. I found using blue painters tape resolved it. My only issue now is trying to get the part off the bed when done. I do heat the bed when using pla.

 

[scottyp]

+1 on the blue tape, no sprays or glues but I only do pla and no experience with other mat. Initial nozzle height setting is probably as or more important. I tend to run it on the closer to the bed side and I’ll take a little elephants foot if it guarantees bed adhesion.

 

[giel]

with the spray it is popping loose if the bed Cools due to crimp of the glass or aluminium bed. and if it won't let go dip it in water this desolves the spray i put my nozzle flat on the bed and turn the z axis leadscrew 4clics on the stepper and when printing around the object a brim for start up detached 5mm away to tune the nozzle height. i used blue tape also,worked well with pla,glue stick wood( pva) glue Lego desolved into acetone polystyrene desolved into paint thinner.. but 3DLACK spray is the best in my opinion. and.for pla sanding the glass with 120 grit paper is also working well until you print at 500mm/s and high objects.

first layer at 120% 0.4 nozzle layer height standard 0.25/0.3

 

[scottyp]

I forgot to add that I run my first layer at half the speed also.

 

[CFLBob]

I've been using those Elmer's purple glue sticks that somebody recommended. "Washable School Glue" that they call disappearing purple. They stick fantastically. Things with a lot of surface area on the bottom stick so well they can be a real pain to get off the bed. But, like I say, this PLA+ filament used to stick well enough without the glue.

I updated the firmware on the printer, did the bed-leveling with the .008 feeler gauge and then the troubles started. Some of it seemed like slicer software, so I didn't mention that one. I should do a post over on my engine build thread describing it all.

 

[chucketn]

I use 'Aqua-Net' hair spray. Start with a clean, properly leveled bed with glass plate on it. Spray a light coat of the hairspray on the glass. Use as is until prints don't stick again, a surprisingly large number of prints. Then wash the glass in warm water with dish soap, re-install glass, level bead, spray... Repeat.

 

[scottyp]

Aqua-Net is also the propellant of choice for potato guns, such a versatile product...

Chuck, I also have an Anet A8 - Works great.

 

[CFLBob]

I set the bed level to .004" (0.102mm) using a strip cut from a soda can and changed the Z offset in the printer software to match.

Immediately, it worked better. I have some old files on my SD card that I've printed before, so I know they work. I set up to print a pair of threaded standoffs I had experimented with a few months ago, and that I had printed with no glue on the bed. The start went well, but about 1/8 or 3/16" up the standoff, one came off the bed and it turned into a mess. Since I never used the Z offset before updating the software, I don't even know if it was in the previous SW, I thought I'd reduce that number. I thought it would lower the nozzle actually below the level I had set it to be with the .004" spacing.

It worked better and I was able to print the two 1/2" tall standoffs with no glue or anything.

Then I went to try a print test I had used last February when I set up the printer. That didn't work as well. The print looked smeared or too wide in places, and then when it was well into the print, the print head pulled some previous squares off the bed and it got really messy really fast.

So it's better, but not completely better.

 

[GreenTwin]

After one print that turned into a bird nest (before I adjusted the head on my printer), I noticed a lot of buildup on the nozzle, which can snag stuff as it moves around.
I cleaned that off.
I guess look for the obvious stuff first.
.

 

[cds4byu]

My recommendation is to add a PEI-coated, magnetically-attached, flexible stainless steel sheet to your printer bed.

https://www.amazon.com/Surface-Spring-Magnetic-Sticker-Printer/dp/B087NPSRZK
Since I bought that, I have had zero problems with bed adhesion, as long as my z-offset is set correctly.

I also use a brass brush to clean plastic globs off of my nozzle, and I use a very lighth coat of plumber's silicone grease applied to and then wiped off of the outside of my nozzle to minimze plastic globbing.

Carl

 

[ddmckee54]

I don't know about your nozzle. but mine tends to drool as it's warming up. Consequently it would sometimes drag a thread of plastic behind it when printing the first layer. This thread would sometimes get buried under the first layer and would cause a small part to let go of the bed during the print. I started folding a paper towel and letting the nozzle come down on top of this pad at the start of my priming strip. (You only need 5-10mm of this wiping action.) The nozzle self-wipes so no more crap on the nozzle and my small parts stick better - as long as I've got the initial bed gap tuned properly.

Don

 

[Foozer]

Ender 3v2
I just level the bed with a piece of paper [Slight drag]
Lite bed spray with Aqua-Net.
Layer Height .2
Initial Layer height .2
Initial Layer Line Width 120% [Extra Squish]
Initial layer Speed 30

Example: PLA 1.2mm wall - No Brim, sticks fine.

 

[CFLBob]

I recleaned the extruder nozzle and ran the bed level squares test that CHEP has on his YouTube channel.

It came out far better than yesterday but still not as good as last February when I did the initial setup.



You can see the places, mostly the upper left corner of the squares, where they pushed/pulled a little under the extruder. This is with no glue or anything else.