<p>I am printing fairly cheap, but highly rated, PLA and not sure whether this is underextrusion or overextrusion; but it just looks bumpy and not clean. My settings:</p>
<ul>
<li>195 °C at 60 mm/s bed temp 50 °C</li>
<li>0.4 mm nozzle at 90 % extrusion</li>
<li>0.1 mm layer height</li>
<li>6 mm retraction at 60 mm/s with 0.50 mm coasting</li>
</ul>
<p>I tried at 190 °C and it severely underextruded halfway through, but the outside looks much smoother; I also tried with and without coasting with no difference and tried adding -0.2 mm extra restart distance which didn't change much either. Could this be because I am just printing a rather small part (25 mm diameter)? I think this because I tried printing a much larger 100 mm diameter hemisphere just before, which printed perfectly using the exact same filament.</p>
<p>I've switched out to a new 0.4 mm nozzle, tried a 0.6 mm nozzle, but the only complete print I got had this rough and bumpy outside. It is printed in the orientation shown as removing support from those thin legs lead to them snapping.</p>
<p>I also had moderate stringing throughout, which I thought coasting and restart distance would fix.</p>
<p><a href="https://i.stack.imgur.com/HfV5J.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/HfV5J.jpg" alt="The small part I'm trying to print" /></a></p>
<p><a href="https://i.stack.imgur.com/v4xCN.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/v4xCN.jpg" alt="The larger part that printed well" /></a></p>
<p>Any ideas would be much appreciated.</p>
<p>Edit 12/04:</p>
<p>I have since reinstalled one of my all metal hotends, as I wasn't using them due to clogging issues, installed a brand new 0.4 mm nozzle, set the extrusion multiplier to 1.0 and disabled coasting. I also calibrated my e-steps, which means I needed to buy an arduino and burn new firmware.</p>
<p>Sadly I didn't print in between fixed, but these are the results I got.</p>
<p><a href="https://i.stack.imgur.com/9T77E.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/9T77E.jpg" alt="enter image description here" /></a>
<a href="https://i.stack.imgur.com/JEcZv.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/JEcZv.jpg" alt="enter image description here" /></a></p>
<p>The prints are <strong>much</strong> better but there is some pretty serious stringing and zits due to me needing to reduce the retraction distance for the hotend to 2 mm, as the 6 mm distance I was using before would make it clog; but since I'm using a bowden extruder it creates stringing. How could I go about fixing this? I feel like I'm playing a game of whack-a-mole.</p>

[{'answer_id': 16023, 'author': 'Abel', 'author_id': 23523, 'author_profile': 'https://3dprinting.stackexchange.com/users/23523', 'pm_score': 1, 'selected': False, 'text': "<p>Cutting materials with a 'hot knife' isn't anything new.  There should be a fairly established toolset for working foam.  For 3D prints, I prefer to add coatings rather than modify surfaces with a hand held tool after.  I do run a drill bit through printed holes though.</p>\n"}, {'answer_id': 16024, 'author': 'Trish', 'author_id': 8884, 'author_profile': 'https://3dprinting.stackexchange.com/users/8884', 'pm_score': 2, 'selected': False, 'text': "<p>I have used a standard soldering iron to modify and fix 3D prints in the past. You have to keep some things in mind when doing so:</p>\n<ul>\n<li>Don't overheat your material. PLA can take a soldering iron of about 230\xa0°C before charring.</li>\n<li>Don't use a tip with solder, or you will get grey deposits in the plastic.</li>\n<li>Round tips or flat tips both work fine, but you want to not dump <em>too</em> much heat into the model or you start to deform the print as it needs to cool again.</li>\n<li>Using snippets from the end of the spool for soldering is a good way to recycle the &quot;waste&quot;.</li>\n</ul>\n"}]
['https://3dprinting.stackexchange.com/questions/16054', 'https://3dprinting.stackexchange.com', 'https://3dprinting.stackexchange.com/users/17392/']