<p>It looks like possibly a combination of too high of extruder temperature and poor retraction.</p>

<ol>
<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>
<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>
</ol>

CC BY-SA 3.0
2016-11-23T21:37:10.827Z
The blobs in the picture look very "watery", which indeed indicate a far too high extrusion temperature. I guess the round drop shape comes from a z-lift movement on retraction, which is usually very useful to avoid nozzle collision during travel moves. On a side note: using a too low nozzle temperature can also cause clogs. If you have no idea where to start, I would try 205-210C for typical PLA, and take it from there.
Tormod Haugene
CC BY-SA 3.0
2016-11-02T14:54:24.230Z
2016-11-02T14:54:24.230Z
tbm0115
<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>

<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>

CC BY-SA 3.0
2016-10-26T20:33:38.693Z
2016-10-26T20:33:38.693Z
Smitje
<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>

CC BY-SA 3.0
2016-10-23T07:14:46.233Z
This is quite short for an answer, and it doesn't do what an answer is supposed to do: how would you *solve* this problem. Change the design? Slicer settings?
Tom van der Zanden
CC BY-SA 3.0
2016-10-24T14:14:42.927Z
@TomvanderZanden it doesn't look like the OP specified their slicing engine. So, it might be a bit premature to suggest slicing settings.
tbm0115
CC BY-SA 3.0
2016-10-22T23:20:43.420Z
2016-10-22T23:20:43.420Z
Jexoteric
<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.sstatic.net/owZtw.jpg" rel="noreferrer"><img src="https://i.sstatic.net/owZtw.jpg" alt="Photo of four balls exhibiting bumps around a cyclindrical through hole"></a></p>

CC BY-SA 3.0
2016-10-22T21:12:34.390Z
Do you have a gcode viewer that lets you see each layer, retractions, etc.?  You might get a clue from that.  And are the sides of the balls printed normally, or do you see distortion in the side wall under each tiny ball?
Fred Hamilton
CC BY-SA 3.0
2016-10-24T12:45:38.300Z
Can you post the original STL, and in addition the slicing tool you're using (and any pertinent parameters you set in that tool)?
Carl Witthoft
<pla>
Weird bumps cylindrical hole
easycheese
# Weird bumps cylindrical hole

(Asked by: username_0 on 2016-10-22)

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.

Note that the hole is supposed to be a cylinder.

[![Photo of four balls exhibiting bumps around a cyclindrical through hole](https://i.sstatic.net/owZtw.jpg)](https://i.sstatic.net/owZtw.jpg)

**Tags:** pla

> **Comments:**
> **username_1**: Do you have a gcode viewer that lets you see each layer, retractions, etc.?  You might get a clue from that.  And are the sides of the balls printed normally, or do you see distortion in the side wall under each tiny ball?  
> **username_2**: Can you post the original STL, and in addition the slicing tool you're using (and any pertinent parameters you set in that tool)?  

---

## 3 answers

### Answer by username_3 on 2016-11-02. Score: 3

It looks like possibly a combination of too high of extruder temperature and poor retraction.

1. First, try ***reducing your extruder temperature***. 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.
2. After you've verified you have correct extrusion temperature. Try ***finding/adjusting retraction settings*** in your preferred slicing engine. Here's a good troubleshoot page from [Simplify3D's website](https://www.simplify3d.com/support/print-quality-troubleshooting/#blobs-and-zits).

> **Comments:**
> **username_4**: The blobs in the picture look very "watery", which indeed indicate a far too high extrusion temperature. I guess the round drop shape comes from a z-lift movement on retraction, which is usually very useful to avoid nozzle collision during travel moves. On a side note: using a too low nozzle temperature can also cause clogs. If you have no idea where to start, I would try 205-210C for typical PLA, and take it from there.  

---

### Answer by username_5 on 2016-10-26. Score: 1

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.

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.


---

### Answer by username_6 on 2016-10-22. Score: 0

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.

> **Comments:**
> **username_7**: This is quite short for an answer, and it doesn't do what an answer is supposed to do: how would you *solve* this problem. Change the design? Slicer settings?  
> **username_3**: @username_7 it doesn't look like the OP specified their slicing engine. So, it might be a bit premature to suggest slicing settings.  

---

