<p>Since this was asked more than 2 years ago I don't expect an answer is still necessary but it might help someone else.</p>
<p>We recently had a PA print with 5 mm internal channels, mostly straight but one was opened up near a 90° bend yet still reachable with a bit of flexible wire. It was possible but difficult to get the powder out. We used a combination of 5 mm drill for the long straight channel and welding wire's in multiples sizes and bent to multiple shapes to get poke it out. A thin bent wire helps to get the last bits out by rotating it in the channels but with a circular channel like you mentioned with 1.5-2 mm diameter I don't see this working as easily.</p>
<p>Compressed air was used at the end to clean it out more, but it does require loosening it up physically because it can still stick to the walls. If you have any small exits (which we did, 0.5 mm) you might get a clogg if it dislodges from air later during use.</p>
<p>Took about 30 minutes to clean up 3 prints with about 1 meter of (mostly straight) channel.</p>

CC BY-SA 4.0
2023-03-22T09:43:15.303Z
2023-03-22T09:43:15.303Z
Renate L
<p>After SLS printing any internal spaces retain the un-fused but packed powder that was in the bed. I am hoping to add channels as wire raceways internal to the part.</p>
<p>Any experiences with this - is it worth the trouble?</p>
<p>More specifically, any recommendations for &quot;flexible-auger&quot; type tools to clean out around the bends?  The residual powder is of a consistency where I expect an appropriately shaped wire could dislodge it.</p>
<p>(Concept, this is polypropylene. Scale: raceways are currently 1.5mm - 2mm in diameter.)</p>
<p><a href="https://i.sstatic.net/9FJqq.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/9FJqq.png" alt="enter image description here" /></a></p>

CC BY-SA 4.0
2020-10-22T17:05:30.767Z
have you tried compressed air?
Trish
CC BY-SA 4.0
2020-10-22T20:56:47.317Z
That was my first thought too.
fred_dot_u
CC BY-SA 4.0
2020-10-23T20:28:43.950Z
Have not yet tried a print of this.  Having previous prints I am pretty sure compression of the powder and friction would prevent compressed air from working.
nate
<sls><cleaning><wire-type>
How can I clean out internal channels in an SLS polypropylene print?
nate
# How can I clean out internal channels in an SLS polypropylene print?

(Asked by: username_0 on 2020-10-22)

After SLS printing any internal spaces retain the un-fused but packed powder that was in the bed. I am hoping to add channels as wire raceways internal to the part.

Any experiences with this - is it worth the trouble?

More specifically, any recommendations for "flexible-auger" type tools to clean out around the bends? The residual powder is of a consistency where I expect an appropriately shaped wire could dislodge it.

(Concept, this is polypropylene. Scale: raceways are currently 1.5mm - 2mm in diameter.)

[![enter image description here](https://i.sstatic.net/9FJqq.png)](https://i.sstatic.net/9FJqq.png)

**Tags:** sls, cleaning, wire-type

> **Comments:**
> **username_1**: have you tried compressed air?  
> **username_2**: That was my first thought too.  
> **username_0**: Have not yet tried a print of this.  Having previous prints I am pretty sure compression of the powder and friction would prevent compressed air from working.  

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## 1 answers

### Answer by username_3 on 2023-03-22. Score: 2

Since this was asked more than 2 years ago I don't expect an answer is still necessary but it might help someone else.

We recently had a PA print with 5 mm internal channels, mostly straight but one was opened up near a 90° bend yet still reachable with a bit of flexible wire. It was possible but difficult to get the powder out. We used a combination of 5 mm drill for the long straight channel and welding wire's in multiples sizes and bent to multiple shapes to get poke it out. A thin bent wire helps to get the last bits out by rotating it in the channels but with a circular channel like you mentioned with 1.5-2 mm diameter I don't see this working as easily.

Compressed air was used at the end to clean it out more, but it does require loosening it up physically because it can still stick to the walls. If you have any small exits (which we did, 0.5 mm) you might get a clogg if it dislodges from air later during use.

Took about 30 minutes to clean up 3 prints with about 1 meter of (mostly straight) channel.


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