Minor PEI bed issues

Hi all,

I’ve been printing on and off (a lot more recently) since last December without issue. Earlier I had a minor nick in the surface, and I have some lines that happened when I was very new to printing and didn’t watch the leveling process closely.

So far printing over the lines shown here:

Leaves a very minor indent / line on the bottom of the print. Not an issue in itself, but it does make me wonder if the PEI material is coming off onto the print.

This scratch feels almost flush with the bed, very minimal, however, my concern is that it may end up attaching to future prints and causing a much larger hole.

I’ve heard of a few solutions, and I imagine I will need to sand the bed down a bit. My concern doing that is getting the sanding level across the entire bed.

I’ve tried to search for similar issues, and it may be that both of these issues are so minor that I can just print over top of them without issue. Just curious if anyone has ideas on how to resolve them both.


It’s good to periodically give a light sanding anyway. It helps with adhesion.

1500-2000 grit on a sanding block. Nice, wide circular motion. It doesn’t really take much. You also don’t need to make it totally disappear.

One thing I would check is to measure the thickness of the skirt on your print. If you’re using standard Cura settings, the skirt should be 0.425mm thick. It’s possible your nozzle is too close to your bed surface. If so you’ll need to add Z offset under Machine: Machine settings: Z-offset. If the nozzle it getting too close to the bed, it can leave marks like that.

It’s just a good thing to check.

Thanks for the feedback!

I ordered a digital caliper that arrives Friday and I plan to check skirt thickness and Z-offset. The lines were from a bad leveling, that I didn’t catch in time.

I’m going to try setting first layer % to 100% down from 125%, and see if that makes prints a bit easier to remove. I may end up having to sand the surface to get prints to adhere with less material holding the edges down.

Reducing the surface from 125 to 100% will definitely help removal at the greater risk of the part warping up from the bed. This can be countered with a brim.

The biggest help I found for removing parts was to get my z height correct. My printer required an extra 0.18mm offset away from the bed to make the first layer thickness 0.425 like cura wants. This made the parts much easier to remove.

Let us know how it goes!


Update: I changed first level down to 100%, and so far no issues with adhesion. The parts are very wide and flat, so there is a ton of surface area to adhere. I just got the Calipers, so I will test Z-Offset later tonight. Parts definitely have a lot straighter sides, and fit together much better, however, they are not quite perfect. I think a Z-Offset will help with the last bit.

I will post some pictures of the parts now versus old when I get home later.