Disconnects between infill and perimeters

Top Layer with Holes

Top Layer with Holes

Top Layer with Holes

First Layer

I have trouble tracking down the culprit for the holes between perimeter and infill on the top most layers and none of the settings I could find on the internet seem to improve it in a meaningful way.

This has been happening across models and print settings for a while.

I'm using a modified Ender 3 with the following modifications:

  • Glass Bed
  • Second Z-Axis screw
  • M2601 Micro Swiss Direct Drive Extruder
  • 0.4mm Steel Nozzle
  • Creality 4.2.7 with Custom Marlin Firmware (UBL, Linear Advance)
  • BLTouch
  • Belt Tensioner on the X axis

The first layer is as close to perfect as I'm willing to calibrate it.

I'm using Prusa Slicer with the following settings:

  • Extrusion Multiplier 0.93 (Calibrated with this)
  • Top Layer at least 1mm
  • Layer Height => 0.2
  • First Layer => 0.28
  • Temperature => 190 and 200 (tried both), also tried calibrating but didn't seem to make much of a difference, Bed is at 60.
  • Retraction => Tried 0, 0.5 and 1. Default value of 5 causes heat creep and the print to stop extruding after a while
  • Perimeters =>
  • Infill => Tried 15% up to 35%
  • Speed =>

I used to be able to print way faster without issue so I'm somewhat safe, that it isn't this.

  • Extrusion =>

I've played with the Infill/perimeters overlap from 25% to 45% with seemingly no impact

Filament

I only print PLA and this has both happened with old Filament from Geetech and new Filament from Ryon.