Good day folks. Question.

3D Printing
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1

Good day folks.
Question. Can someone help me identify what could cause only the second layer perimteter under extruding? Here’s a 20mm cube that shows it.
Hictop Prusa i3
Repetier-Slic3r
.20mm layer
.10 mm nozzle clearance when cold
PLA. 192° with 70° bed.

First layer goes fine. Second layer perimeter goes very thin. Third layer and up are fine. This occurs on all prints regardless of layer height.

Also, what settings could I edit to minimize the start of the layers from bulging as seen on the corners? I was thinking maybe printing from infill towards perimeters instead. I tried random start points and made the sides look pretty crappy with random zits. I tried adjusting extrusion and retraction between layers without noticeable diff.
Thank u folks. Have a great day.

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2

Extruder seems to be to close to the bed, slightly clogging the xtruder on the second layer. Multiple problems mixing here. Can’t analyse without more pictures.

3

  1. The second layer being weird may be because it is making up for the first layer height not being correct.

  2. The nozzle looks like is heating up and cooling down. My guess is your PID needs to be tuned based on the waviness horizontally. It is looks more evident at the bottom probably because of the heated bed adding to much heat or the cooling fan cooling off your hotend too much.

  3. There is a ghosting effect. Maybe related to printing speed.

  4. There are also what looks like Z banding every 8 layers. Probably something with your Z axis.

  5. Might try printing on blue painters tape with the heated bed turned off to see if all the extra added heat from the bed is part of the problem with 1 and 2 above. I do this with PLA at 225C for all layers and no fan for only the first layer.

4

Also, bulging on the corners is probably because of speed or acceleration.

5

Thanks. I promise I’m sucking all the info I can to get better at this. Keep reading and studying daily. I’ll make some adjustments soon and see what can I do

6

I’m 99% sure i know what your issue is, as i’ve experienced the same thing a few years ago: Heated bed flex.
As your heated bed cools down (or stops heating) aroudn the time the second layer prints, it flexes away from the nozzle and physically moves the print down. Put a dial gauge on the bed to diagnose it, then switch to a better heated bed solution (silicone + aluminum) to eliminate it.

7

Update… I think the Y axis 8mm smooth rods are not perfectly straight… i calibrated the bed again to 0.10mm… made sure nothing was loose etc,… and printed a test empty cube with no heat etc… look much better… but noticed some layers shifted X when i rotated the left smooth rod as it was printing and i was making sure everything was tight… it does move the bed if i rotate the rod… so at least i know i do have some thing potentially messing with me

8

Agreed with @William_Cooke1 ​