<p>I just switched to the Duet Wifi board (used MKS Gen L 1.0 before) and now small structures look terrible. From my observations the hot end moves correctly, but almost no filament gets extruded. On the other hand larger structures look very good. With the MKS board the exact same G-code worked fine.
After that I gradually disabled many features like coasting, wiping and even retractions altogether, the quality only improved by a tiny margin.</p>

<p>Example print (the two towers should be cylinders):
<a href="https://i.stack.imgur.com/jE94g.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/jE94g.jpg" alt="Example print"></a></p>

<p>Additional information:</p>

<ul>
<li>Printer: JGAurora A5</li>
<li>Material: PETG</li>
<li>Slicer: Simplify3D</li>
</ul>

<p>More info (edit):</p>

<ul>
<li>Hot end temperature: 225&nbsp;°C (for the affected layers)</li>
<li>Bed temperature: 60&nbsp;°C (I corrected the thermistor data, it's equivalent to 70-75&nbsp;°C on other JGAurora A5 printers)</li>
<li>Nozzle diameter: 0.4&nbsp;mm</li>
<li>Part cooling fan: 100% (improved cooler duct by Da Hai Zhu)</li>
<li>Print speed: 50&nbsp;mm/s (50% for outline)</li>
<li>The cylinder is printed hollow because of my infill settings</li>
<li>Lubricant is fresh, belts are tightened, so there should be no mechanical issues</li>
</ul>

[{'answer_id': 10163, 'author': 'Nach0z', 'author_id': 16621, 'author_profile': 'https://3dprinting.stackexchange.com/users/16621', 'pm_score': 0, 'selected': False, 'text': "<p>This actually just looks like heating issues. Cura has an option to set a minimum layer time and speed, and any layer that takes less than that amount of time it'll lift the head away from the print to allow the plastic to cool.</p>\n\n<p>Unfortunately, the only things I can find for Simplify3D around head lift and minimum layer times are software feature request posts from 2017, or some features around scaling print speed for small layers, but unfortunately that'll just print the same object much slower and may not properly allow the part to cool as the melting-temperature print head is still sitting directly on top of the part.</p>\n\n<p>I hate to be someone to suggest a software change, but you might try using Cura and seeing if you get better results with features such as this. </p>\n"}, {'answer_id': 10169, 'author': '0scar', 'author_id': 5740, 'author_profile': 'https://3dprinting.stackexchange.com/users/5740', 'pm_score': 3, 'selected': True, 'text': '<p>The OP found the solution and shared this in comments but has not written a proper answer. The OP found:</p>\n\n<blockquote>\n  <p>To complete this, the issue was related to the part cooling fan not spinning correctly. After replacing it the problem was gone.</p>\n</blockquote>\n'}]
['https://3dprinting.stackexchange.com/questions/7963', 'https://3dprinting.stackexchange.com', 'https://3dprinting.stackexchange.com/users/14194/']