PETG suddenly not sticking to glass plate anymore

[broutilde 2]

Hi! Hope you're all doing well.

I have a 2+ that I've been using for two months, printing quite a lot as I'm making a PETG mount that started having a lot of success on Etsy. Anyways I decided to do some light maintenance on my printer yesterday: lubricating the axle and retightening the hot end isolator.

After doing the latter, I thought it would be wise to level the build plate (which is something I do pretty often).

I started printing some PETG components again and the filament wouldn't stick. I usually apply a thin layer of stick glue. I haven't changed anything, it's the same file that I'm using, same filament (Polymaker Polymax 2.85mm), same everything. I removed and cleaned the glass plate, printing directly on it without glue this time. It stuck so well that I couldn't remove my prints afterwards hahaha...

Now I'm trying again with a thin layer of glue, after leveling the plate for the 4th time..Still not sticking.

Anything else I should try to do? I'm at my wits end and have many orders to fulfill.

Thank you

E.

[Smithy 1,146]

There are only two possibilities, level a bit closer to the bed to increase the adhesion or try another adhesion agent. For PETG hairspray, Dimafix, 3DLac or Magigoo is working. 

 

Strange is that it was working before with the same glue stick as far as I understood. So I would try to level a bit closer and try it again.

[gr5 2,228]

You are "leveling it wrong".  Which is very common and very understandable and I don't know what you are doing wrong just that you need more squish.  So don't level any more - just turn the 3 screws counter clockwise as seen from below to move the bed closer to the nozzle.

 

Turn all 3 the same amount so you don't have to do the leveling procedure again.

 

It's 0.5mm per full turn so try turning half way, start the print and be ready to turn them some more when it prints the skirt or brim.  Remember - CCW as seen from below squishes more.  CW squishes less.  If you practice this at the start of every print eventually you will be able to do it without thinking.  Anyway that's not ciritical as once you get the leveling perfect it should stay great for many months (or until you change the nozzle or other hardware that changes the nozzle position).

[broutilde 2]

On 2/13/2022 at 12:48 PM, gr5 said:

You are "leveling it wrong".  Which is very common and very understandable and I don't know what you are doing wrong just that you need more squish.  So don't level any more - just turn the 3 screws counter clockwise as seen from below to move the bed closer to the nozzle.

 

Turn all 3 the same amount so you don't have to do the leveling procedure again.

 

It's 0.5mm per full turn so try turning half way, start the print and be ready to turn them some more when it prints the skirt or brim.  Remember - CCW as seen from below squishes more.  CW squishes less.  If you practice this at the start of every print eventually you will be able to do it without thinking.  Anyway that's not ciritical as once you get the leveling perfect it should stay great for many months (or until you change the nozzle or other hardware that changes the nozzle position).

I wish I had someone on hand who could come and show me. I feel lost. I tried to squish more, it's still making a nice little ball of PETG. I tried the calibration card too, and the nozzle is nicely scratching its surface but lightly. I tried to reduce the speed to 30 too. 

Tonight I'll try to squish even more, will clean my plate and restart from 0.

It stresses me out a lot as I have orders in and don't want to disappoint people.

Sighs.

[Smithy 1,146]

Can you post some pictures that we can see how it looks like?

[broutilde 2]

So I would like to give a huge thank you to @Smithy  and @gr5, you guys helped me out of this situation.

I took time to look at my nozzle when printing and adjusted all the knobs like gr5 suggested, and could finally judge the "squishiness" of the filament. I only had to turn 1/4 turn ccw and it worked! I have a better idea now of what to look for when it comes to the plate/nozzle distance.

I also bought some hairspray and it's working great.

@Smithy do you clean the hairspray every print? Or do you add more layers? I might get another plate if I have to take it out and clean it every print.

Again, thank you so much guys, I felt defeated and dumb and now I feel like I can make it work!

[Smithy 1,146]

You are welcome!

 

13 hours ago, broutilde said:

do you clean the hairspray every print?

No,  I clean the glass maybe every 10-20 prints, depending on how it looks like. So absolutely no need to clean it after every print job.

[gr5 2,228]

You can keep adding another layer of hairspray occasionally and then when you can't stand it any longer (ugliness) clean it at that point.  I clean about once every 300 prints and start over.  Often because I have a new print coming up that will be longer than usual - say a 10 hour print - or the glass is just so ugly - or a print that is larger than usual on the plate and likely to warp - or a combination of these reasons.

[gr5 2,228]

Also don't let the hairspray get on the z screw or other components.  Take the glass out before spraying or protect them in some other way.  I don't use hairspray anymore but an equivalent glue that is painted on.  I use 1 part wood glue and 10 to 30 parts water shaken in a jar and applied with a paint brush and then wait for it to dry (dries faster if heated bed is hot).

[Jasonjason 6]

Is that pva wood glue you use?   Sounds easier than a glue stick….

[geert_2 558]

Look at the bottom of your prints: if it shows round sausages, it is not squished enough. If the bottom is nice and flat, it is okay.

 

Mine usually look like this:

 

 

[gr5 2,228]

@Jasonjason - I mix elmer's wood glue with water.  Very roughly 20 parts water to 1 part wood glue.  I put it in a jar and shake it up good.  Then remove the lid and use a dedicated paint brush to paint the glass.  This tends to last about 10 to 100 prints before I recoat.  Every year or two I soak the glass in warm water and laboriously scrub everything off then when it looks 100% clean I do one final cleaning with glass cleaner and then am very careful not to touch the glass until recoated.

[gr5 2,228]

Glue stick isn't difficult.  If I use gluestick then I just put a little on and then take a wet tissue and spread it all around (and also the bonus is this removes 90% of the excess glue).  If I don't want the part to stick too much then I put on lots of glue stick and don't remove any of it.

[Smithy 1,146]