I am having problems with bed leveling,

3D Printing
,
1

I am having problems with bed leveling, did some testing and it seems my bed is no longer flat, or no longer almost flat, now it has a concave shape but with random high spots. I am highly suspicious of the 3m transfer tape under the PEI. anyone have issues with that compressing or expanding with heat, or repeated print removal? Wondering if I pressed a valley into it removing prints while the 3m transfer tape was still hot…

2

I had issues with the 3M tape and PEI, but I was getting visible air bubbles after lots of use. Pulling off parts while the bed was still hot seemed to be the cause.

3

I use 3mm float glass; from your local glazier only costs a few dollars and is as flat as needed.

4

Glass kicks ass! :wink:
Another good tip is to convert your bed to 3 levelling screws if it has 4. It’s next to impossible to correctly level a flat surface with 4 points. (unless you can break the laws of physics)

5

@Martin_Dolan how do you recommend yo do It? I have a prusa i3 clone. Thanks in advance

6

Ok, well there are 2 ways of doing a three point level.

I don’t have your model printer but the concept is the same.

One is just remove one of the corner screws. That will give you a triangle. (three points)
The other way that I did with my wanhao i3 touch clone is to take off the heater plate and see if there is an extra hole. On mine it was in the middle of the back. I removed both back screws and just put one of them in the middle hole.
If you intend to use a glass plate on top as your build surface then you might need to countersink that hole a little so the screw does not stick up higher than the build surface.
You can do this to the heater plate as long as you don’t cut or damage the heating element tracks underneath. Also make sure that you use insulating washers etc.
You can even drill a new hole through the heat bed if there is isn’t one there. Again make sure you are very careful of heating element tracks under the plate and don’t go near them.

The method of levelling the bed is a little different with three points but there are lots of videos on youtube for that.

This is what mine looks like with the back two screws converted to one.

missing/deleted image from Google+