So no two filaments are the same, are they?

Well, I’m switching back to Hatchbox white PLA. The yellow really doesn’t like me. Still Hatchbox, still plain PLA, not PLA+ or anything crazy. The first layer goes down and the extrusions don’t touch each other at all! I can pull on on end and it just unravels off the bed like when Bugs Bunny snags his sweater on a nail and it unravels without him even knowing…

What causes that? The filament thing - not the Bugs Bunny thing…although go ahead - let’s hear those theories too…

Pictures please

I use different brands and colors on printers with different extruders all with the same gcode. Something is fishy with your build still. My prints get knocked off the bed after some cooling with the HANDLE of a large knife acting as a hammer, sometimes I have to hack at them with the blade.

[attachment file=77195]

…of course. Now it’s like “Hey - he’s watching. Smarten up or he’ll install that sensor!”

The layer is looking just fine so far…give it time. It’ll hiccup :wink:

Nope I lied. It looked good from far but far from good. I thought maybe the filament was a little translucent and that’s why it looked that way but after so many detachments and fails today I didn’t trust the print to just let it go overnight. So I stopped it to poke at the first layer and sure enough…

This IS just the raft layer - does that have anything to do with it? Slic3r settings all the same as when I was rocking it through the whole spool of white (other than a 5 layer raft vs a 2 layer raft…was desperate for adhesion ; )

I’ll try doing nothing but switching filaments tomorrow (back to white) and see what happens.

Why don’t you install the BLTouch? If you keep having first layer issues that seems like a good solution to me.

We need way more information to know what might be wrong:

-What is your bed material? Glass? plain aluminum? Some other weird stuff?

-Is it heated? what temp?

-Did you put anything on it? glue stick? spray hair gel? something else?

-what are your actual first layer height and your nozzle diameter?

-did you try a lower first layer height? What happens if your first layer is squished tighter on the bed, will it stick?

Right now it looks to me that your bed surface is not well prepped and that your layer height is too high, but without any actual data it is just a wild guess. Love your videos though, if only everyone asking for help was doing this it would be way easier for us to troubleshoot.

My advice to get a perfect adhesion on PLA: glass bed, preferably heated but not absolutely necessary, and glue stick all over it 5 minutes before printing without heat activated, or 3 minutes or less if heat is activated (don’t wait too long, at some point it becomes less effective). A dirty glass plate is, in my experience, better than a perfectly clean one in terms of adhesion (as long as there is no oil on it, of course), but it gives a poorer finish.

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I still think it’s the bed. You need an intermediary between the pcb heater and the pei.

That’s how my rafts look in slic3r and s3d, they aren’t supposed to touch. Try without a raft and see if it’s the same.


This is an mk3, which is has a built in aluminum bed. You flip it so the pcb is on the underside and print on the aluminum (with tape, or pei in my experience):

The mk2 is just a pcb and it needs glad or aluminum on top.

I bet your right. They look pretty good if they were supposed to be spaced like that. They did come up easily, but you’re pulling on single extrusions. IDK about Ryan’s hammer knife, but I bet his shirt material comes up without Thor’s kitchen knife.

Did your white pla raft create a solid plate? The two things that would easily change is it’s response to temperature (the white might run easier at this temp and extrude more) or thickness. I doubt the thickness is off by enough to make that much difference. The third thing is that you tugging on things while changing filament messed with the bed level or something.

Yeah there is something wrong for sure. This is how it should look and feel…

Link to video

I have never tried to embed a youtube video into the text so I am not sure if this link will work. (Looks like it didn’t) How do you guys do that? embed the video into the text?

But in the video you can see how the first raft layers are spaced out and how they are very well stuck down. I can scratch them and poke them and they stay down pretty well.

This print is using Hatchbox Black PLA 205C and 60C on the bed. The print is set to run at 60mm/s but the first layer of the raft is set to 22.5 mm/s. The bed is lined with the 3D Build Surface bed liners I have been talking about. They work miracles but these ones warp at the seems so the bed is not a flat surface. I ordered a replacement that is large enough to cover the entire print bed so I don’t have to piece several together.

When it is done printing I will show a video of what it takes to snap it off the bed. I have to use a stiff Paint Scraper and smack it a few times even with the bed cooled down. (Just like Ryan described.)

I think you will need to replace your PEI. But if you want a faster solution for the time being I agree with Dui, ni shuo de dui. Try some glue stick on the current PEI. Apply a thin even layer to a cool bed. PLA loves to stick to gluestick. I just wonder if the PEI will play nice.

I also wonder if your heat bed is maintaining an even consistent temperature. Do you have one of those temperature guns you can point at the bed and read the temp? I used one of those and found a cold spot on a print bed once.

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If you just put the link on it’s own line, the website does it (it’s counter intuitive to everything else):

Those layers look super smooshed to me, but maybe that’s what you’re going for with a raft. Yours also has an outside border, which will help a lot. I haven’t used a raft in a really long time, so I’m always trying to get my first layer to not be smooshed, but maybe you’ve got the stress free secret.

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Yes, I am intentionally smashing the first layer a little more than necessary I find that helps to make it stick better but it only works with a raft because then there is a space between the lines so they don’t knock each other loose. Long ago I figured out how to do it without a raft with settings like First layer height of .2 and 400% thickness but it was a bit touchy. the Z homing height had to be perfect and since I don’t have a bed leveling probe that can be a problem. So I cheated. I use the raft and it compensates for a lot of problems like bubbles, bumps or unlevel surfaces. And since I started using these bed liners my bed adhesion failure rate has dropped to less than 1%. Last week I noticed one of the corners of the bed popped loose causing the bed to be very unlevel. I think I had been printing smaller objects in the center of the bed for a few weeks before I tired a bigger object and had the print fail. I didn’t even notice how unlevel it was for a while.

Thank you for the tip on the embedded videos.

My other job is as a professional procrastinator. And I was rocking some full bed prints there for a while and thought maybe that’s how the sensor worked - you just put it near the machine and the machine is like, “Okay, I better print good or he’s gonna start snipping my wires again…”

It’s PEI 3m taped (full sheet) to the aluminum bed. I didn’t know the need for the PEI until I had already almost built the MP3DP so I ordered what I could find on Amazon - not from Ryan’s “proven” sources.

I heat to 60, 63 if I feel maybe I’m not melty enough.

Just hopes and dreams…

.32 - 4mm nozzle (205 deg 1st layer, 200 after)

This is one thing I haven’t tried monkeying with ever. I set my 1st layer height to .32 when I first set up Slic3r and have never touched it. I have started printing all other layers at .25 and it seemed to work well but I’ve never tried the first layer - instead twisting the Z end stop a quarter turn this way or that.

Well this is VERY interesting. Maybe I should have let it go. I’ll try that first here - I need to heat up to pull the filament anyway.

Holy moly! I’ve been nervous to go from 30 to 33! First layer is set to 35%

I think I’ll order up what I need for a new bed first, then try this - just in case PEI and UHU don’t get along.

Any excuse to buy new toys…er…tools is welcome. I’ll watch the flyers. I could almost see this as an issue EXCEPT that I was under the understanding that PEI doesn’t even really need heat to begin with. Or was that just clever marketing?

Thanks once again for all the help and support! Beers all around ; )

Might just be acrylic (starting to look that way) check the reviews and see if anyone else has proven this. Just as a triple check Windex the surface with a magic eraser, then alcohol and try again.

To me your first layer looks perfect and should stick as is. So either that is not PEI or your bed is not actually 60C. At 60-63C my pla stays soft and actually stretches and flexes, your was looking brittle and hard. So I am not convinced either way. Maybe heat up your nozzle and bed to 60C and see if there is a huge difference by feel if you don’t have a way to measure it.



When I taped off the fan the PLA on the bed stayed nice and gooey for me so I think the bed heat is working OK. Prior to that it was hard as soon as the nozzle passed (so to speak).

This is the one - unfortunately only four reviews on the Canadian Amazon. but they sound good…except at high temps. I should confess if I haven’t already done so…there was one day that I forgot the machine was on and warmed up and it sat like that all day. Maybe that warped things just enough to be an issue?

I’m laying down another yellow first layer now and it all looks ok so far (touch wood). I’ll let the print go as long as it’ll go. FYI - the raft is to support two J-motor mounts, a new LCD body and the one remaining corner lock that’s been bugging me (I have two viable ones but the raft stuck to them so I’ll need to sand them carefully).

However, the reason for the gang print is because I tried the LCD body three times and it popped off halfway each time - the prints looked great up to that point. I tried oriented on the X, on the Y and offset on the bed to avoid known trouble spots. Now I’ve ganged the pieces together tight enough that the rafts will connect - hoping that it holds the LCD body for me which is the point I want here. I need the others but I want the LCD sooner than later because I’m dusting up the board on the MPCNC like crazy these days ; )

I think you are thinking about PLA. PLA doesn’t need the heat to stick to many surfaces like glass, glue, tape, PET, (And I think) Aluminum. That is why many printers can get away without a heated bed. But PLA still sticks better to a heated surface.

PEI is a little different. PEI does need the heat to make it sticky. In the words of Tom S…

Also I found his video on maintaining and restoring PEI.



I didn’t know so many people still used rafts!

The one time I used a raft, I couldn’t get the print off it. I have the same issue with supports. Doesn’t help I print with petg.