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I'm printing part for a chess board from a set on Thingiverse, expanded a little to 50 mm square. After the 3rd layer, I'm seeing what looks like raised ripples, and you can feel them with a finger too. I didn't see this when printing just 4 pieces earlier. PLA at ~200 °C, bed is PEX/flex steel/magnet/AL.

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The initial layer also had some streakiness (?) after the 1st layer.

Odd, as the bed tests out as pretty level using the paper under the nozzle test.

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Looking much better now that the infill is starting. Will have to look into calibrating the extruder when this print finishes. Printed a 6 hour iPhone stand yesterday, turned out really nice.

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Top layer is nearing done (looks like top layer is finishing, then the lip to go for the edge of the board) and all signs of the rippling are gone. Will check the 'level' again before we start on the light color squares.

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    $\begingroup$ Most probably your nozzle is too close to the bed, hence the strange first layer. $\endgroup$ – 0scar Jun 30 '19 at 21:35
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It looks like over-extrusion. When layers are printed with 100% infill, excess material has nowhere to go and these characteristic ripples form.

Always calibrate your extruder. 3D Hubs have a good article on the topic:

How To Calibrate, Tune and Fine Tune your printer and filament

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  • $\begingroup$ So the ripples will be 'absorbed' so to speak when yet to come 20% infill layers start? $\endgroup$ – CrossRoads Jun 30 '19 at 19:08
  • $\begingroup$ If you are over-extruding, you need to fix it, since it will cause other problems. $\endgroup$ – Mick Jun 30 '19 at 19:12
  • $\begingroup$ I think it's just "bed too high". $\endgroup$ – R.. GitHub STOP HELPING ICE Jun 30 '19 at 19:51
  • $\begingroup$ I was thinking it could be that too. Wish I had a way to machine the bed flatter or something to deal with the odd layer 1 streaking, as it looks just right in some places, intermixed with too high or too low in others. $\endgroup$ – CrossRoads Jun 30 '19 at 20:14
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    $\begingroup$ Could be over-extrusion, but also the nozzle is a little too close to the bed. $\endgroup$ – 0scar Jun 30 '19 at 22:45
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Printing some more parts tonight. Looks like solution is better bed "leveling" (tramming, or basically squareness between X, Y, and Z axis). Getting it dialed in to the correct height, 1/4 turn of a bed leveling screw at a time.

Also ordered some metal (stainless steel) shims so we can get and check the bed level more accurately than "this index card plus a little bit" as the card measures ~0.16mm and we want 0.18mm to 0.2mm or maybe 0.22mm it seems.

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  • $\begingroup$ Turned out better bed 'leveling' was the solution. While printing the white squares for the chess board, I printed them in pairs, I adjusted the leveling screws a little each time until I achieved a very nice first layer, not too squished (creating blobs) and not too thin (didn't stick well enough to PEX on heated bed), but something in between that looks very nice. Will try to measure with the shims and see just what it is. $\endgroup$ – CrossRoads Jul 5 '19 at 14:18

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