<p>Printer: Ender 3 Pro - Direct drive, BLTouch, stock magnetic print bed surface<br />
Material: PLA - multiple brands</p>
<p>Slicer Settings:</p>
<ul>
<li>Layer Height .2 mm</li>
<li>Initial Layer Height .1 mm</li>
<li>Line Width .4 mm (with .4 mm nozzle) and also tried .39 mm</li>
<li>Wall thickness 1.2 mm (3 lines)</li>
<li>Hot End 210 °C</li>
<li>Bed 60 °C</li>
<li>Print Speed tried between 40 and 100 mm/s</li>
<li>Retraction Distance 6 mm  speed 25 mm/s</li>
<li>Print Cooling- Initial 3 layers 0 %, then 100 %, also tried 50 %</li>
</ul>
<p>I designed this in Tinkercad and sliced it with Cura for the Ender 3 Pro.  When I print this specific shape at this size the outer wall does not print properly, there are large gaps and it does not bond to the rest of the model so it just flakes off as soon as you handle it.  I can print other shapes fine- see the color swap example that was printed with the same settings successfully before AND after this series of failed prints of the same design.  Sometimes I get a clean first 15 layers then it goes to crap, and cleans up for the last 10% or so.  If I scale it down to 50 % it prints fine, but it will NOT print properly at full scale.</p>
<p>The infill and inner walls seem fine, but the walls are definitely not air-tight with what is left.</p>
<p>Looking for more things to try and troubleshoot, so please send me your ideas!</p>
<p>Troubleshooting steps so far:</p>
<ul>
<li>Re-downloaded the files and resliced with all new settings</li>
<li>Adjusted the print speed, wall line width and fan speeds</li>
<li>Tried multiple PLA types and brands</li>
</ul>
<p><a href="https://i.stack.imgur.com/4D9iC.jpg" rel="nofollow noreferrer" title="Printed model with printing errors"><img src="https://i.stack.imgur.com/4D9iC.jpg" alt="Printed model with printing errors" title="Printed model with printing errors" /></a></p>
<p><a href="https://i.stack.imgur.com/BNu8J.jpg" rel="nofollow noreferrer" title="Printed model without printing errors"><img src="https://i.stack.imgur.com/BNu8J.jpg" alt="Printed model without printing errors" title="Printed model without printing errors" /></a></p>

[{'answer_id': 17863, 'author': 'Samuel Comeau', 'author_id': 30649, 'author_profile': 'https://3dprinting.stackexchange.com/users/30649', 'pm_score': 0, 'selected': False, 'text': "<p>You appear to have severe underextrusion. It may be that you are trying to melt plastic faster than your printer can physically accomplish which would explain why it starts good and then the nozzle gets cold and then as the layers get small it comes good.\nThat doesn't explain why reducing the print speed doesn't help. Double check that it is actually slower.\nI have had similar issues with cura that were fixed by altering the configuration, like tilting the model slightly or changing print orientation.</p>\n"}, {'answer_id': 17869, 'author': 'Kezat', 'author_id': 30645, 'author_profile': 'https://3dprinting.stackexchange.com/users/30645', 'pm_score': 1, 'selected': False, 'text': "<p>Assuming you do have a direct drive system as described.\nIs this correct?</p>\n<blockquote>\n<p>Retraction Distance 6 mm speed 25 mm/s</p>\n</blockquote>\n<p>A retraction distance of 6 mm for direct a drive is huge and could easily be pulling the filament out so far it might become problematic. Most of my direct drive printers are 0.4 to 1 mm. In addition the 25 mm/s appears to me to be on the low side, though it would not surprise me if it's highly extruder specific. Most of my retraction speeds are 60 to 90 mm/s.\nFaster retraction speeds can actually be more effective at stringing reduction then adding distance as. Faster travel will also reduce stringing as the nozzle has less time to ooze.</p>\n<p>Are you incorrectly a using a Bowden profile?</p>\n"}, {'answer_id': 17909, 'author': 'Zeiss Ikon', 'author_id': 28508, 'author_profile': 'https://3dprinting.stackexchange.com/users/28508', 'pm_score': 1, 'selected': False, 'text': "<p>Promoted from comment: if you had switched from a higher temperature filament to lower temperature, you need to purge the hot end at the higher printing temperature to ensure the old filament is sufficiently fluid for the new to push out.</p>\n<p>If you don't do this, pulling the old filament may leave a &quot;core&quot; passage that lets the new filament get to the nozzle, more or less, but the lining of old filament in the nozzle will both limit thermal transfer (plastics are generally poor conductors) and restrict flow even when the new filament is well melted.</p>\n<p>This will result in a preheated nozzle printing acceptably until the filament carries away too much heat, then grossly underextruding when the flow rate rises (larger layers, print speed increasing after initial layer slowdown), and potentially partially recovering when the layers get smaller or (due to slicer settings) the print speed slows near the top of a tall part.</p>\n<p>Solution: when switching filament, ensure that your purge cycle (whether manual or automatic) is done at the higher temperature for the two filaments involved -- if switching from PETG to PLA, for instance, you'll likely need to purge at 220\xa0°C or higher, even though you'd print your PLA at 180-220\xa0°C,</p>\n"}]
['https://3dprinting.stackexchange.com/questions/17848', 'https://3dprinting.stackexchange.com', 'https://3dprinting.stackexchange.com/users/30617/']