<p>Not quite sure what's happening here. I printed it as a single ball and had this effect. I thought it might be a cooling issue so I printed 4 at once but the issue still occurred. If I size the ball up, the problem reduces.</p>

<p>Note that the hole is supposed to be a cylinder.</p>

<p><a href="https://i.stack.imgur.com/owZtw.jpg" rel="noreferrer"><img src="https://i.stack.imgur.com/owZtw.jpg" alt="Photo of four balls exhibiting bumps around a cyclindrical through hole"></a></p>

[{'answer_id': 2958, 'author': 'Jexoteric', 'author_id': 4654, 'author_profile': 'https://3dprinting.stackexchange.com/users/4654', 'pm_score': 0, 'selected': False, 'text': '<p>It looks like it is trying to fill in what might be small gaps and is putting blobs down because the gaps to too small of a detail to accurately fill.</p>\n'}, {'answer_id': 2987, 'author': 'Smitje', 'author_id': 4406, 'author_profile': 'https://3dprinting.stackexchange.com/users/4406', 'pm_score': 1, 'selected': False, 'text': '<p>In order to exclude a cooling issue, you could try printing a larger object alongside the spheres. Something that has a constant cross-section and is at least as high as the spheres.</p>\n\n<p>I have had issues when printing objects with a sharp tip, even printing 8 at once the total amount printed on the top layers was not enough to let the material cool before the next layer.</p>\n'}, {'answer_id': 3011, 'author': 'tbm0115', 'author_id': 98, 'author_profile': 'https://3dprinting.stackexchange.com/users/98', 'pm_score': 2, 'selected': False, 'text': '<p>It looks like possibly a combination of too high of extruder temperature and poor retraction.</p>\n\n<ol>\n<li>First, try <strong><em>reducing your extruder temperature</em></strong>. PLA ideal extruder temps range from about 185C to 225C; depending on purity, quality, and climate. This can help prevent additional oozing and clogging. If your extruder clogs easily, you probably have too high of temperature.</li>\n<li>After you\'ve verified you have correct extrusion temperature. Try <strong><em>finding/adjusting retraction settings</em></strong> in your preferred slicing engine. Here\'s a good troubleshoot page from <a href="https://www.simplify3d.com/support/print-quality-troubleshooting/#blobs-and-zits" rel="nofollow noreferrer">Simplify3D\'s website</a>.</li>\n</ol>\n'}]
['https://3dprinting.stackexchange.com/questions/2955', 'https://3dprinting.stackexchange.com', 'https://3dprinting.stackexchange.com/users/4378/']