Trick for cleaning trapped resin out of blind holes

General Discussion
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I wanted to share a new trick that we recently learned for ensuring small, deep, blind holes came out clean from the wash every time.

We were printing 200 of these enclosure parts for a client and these small standoffs for self threading screws were always coming out of the wash with resin still in it.

Simply by using an allen key to force the resin out pre-wash, this ensured that IPA would make its way into the holes. My guess is that surface tension and viscosity play a role here in preventing IPA from cleaning the hole properly if there is trapped resin inside.

I know we all have our own different workflows and post processing tricks, but just wanted to share :raising_hands:

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Hey @leonhart88

Thanks for sharing!
Getting resin out of thin deep holes can always be a struggle, this is a cool trick that will definitely help people with their projects.
I sometimes use a dental pick or wax carving set to do similar things on my parts, just like you I am not a fan of using compressed air as that just flings resin everywhere. Some people have grabbed cardboard boxes and blown off parts in there, in the dental space some people have tables with a hole in the middle and a garbage bin below that, which they use for cleaning with compressed air.

What I’ve done a couple times is adding a small hole into long standoffs that goes sideways and makes the screw hole into a throughhole (without going to the outside of the part), using some of the stiffer resins be careful with that technique as it can influence the integrity of the standoff.

Mic quality is nice btw, no complaints.

Kind regards
Jakob

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+1 on dental tools. I can never go back to any other type of tool for fine detail work. Nail tools are also very precise for painting and sanding, but still not on the level of dental. Back in college, I also used a water flosser with IPA in an enclosed glove box (not recommended) to clean out difficult channels. Now I just get by with some large syringes and some small nozzles for higher pressure and flow rate.

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As soon as I posted this video, a friend who runs a larger service bureau (3DS + Stratasys machines) literally told me to try using dental tools :sweat_smile: I’m going to order some and see how their fare. I kind of like the simplicity of cleaning an allen key versus dental disposables, but we’ll see how it shakes out.

Agree on modifying to make parts through holes…unfortunately I don’t always own the design portion of parts we print :cry:

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Omg, I can’t imagine how messy a water pik would be with IPA :joy:

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Even if you don’t own the design you could add the small holes (to allow IPA in and out) in Preform if the design owner approves?

I like to remove as many manual post processing functions as possible by “design for additive” mods. As they can be missed or not done properly causing quality issues.

Great video BTW :+1:

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Yeah, actually thinking about this one - I probably could very well add a side hole to these standoffs, especially since these are internal and not visible. I might actually do this on the next run of parts.

I can’t always make changes like this, but I think it’s totally appropriate for these ones :raising_hands:

And thanks, trying to share knowledge as much as I can when I have time to make content even if it’s a very niche topic :upside_down_face:

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Hey Andrew, I want to learn more about reducing post-processing time & complexity, so I’m curious what you mean by “design for additive.” Are there specific practices or techniques documented somewhere that you’re referring to? Or are these your personal learnings over time??

I’d love to learn more from you and others in this forum.

Thanks, Rob

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He’s referring to doing things like turning blind holes into through holes to make washing and post processing easier (relevant to my original post).

Or designing parts so they don’t have suction cup areas, minimal overhangs, can be printed directly on the build plate, etc.

There are lots of pain point around post processing so designing for additive just means designing the part to minimize those pain points.

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@RobSinclair Mostly I try to make sure that where the support touch points attach to the parts are in areas that are easy to access if they’re are going to affect the function or aesthetics.

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That’s a really practical tip! Using an Allen key to pre-clear the resin makes a lot of sense—surface tension can definitely trap liquid in tiny cavities. I might experiment with this on some of my deep blind holes too. Have you noticed any risk of scratching or damaging delicate features when forcing the resin out, or does it generally work fine for most small parts?

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I haven’t noticed any issues. Just pick an appropriate sized tool :sweat_smile:

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I use a syringe with a needle at the end, works great!

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Yeah I’ve done this before too, along with a squeeze bottle. I just find it a little messy at times :sweat_smile:

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@leonhart88 which resin made the parts in this video? Always good to have details like that in the description even if you don’t mention them in the video, like people put their camera gear etc! Sorry if you already did - I watched the video when it came out and am on a low rate connection where I can’t load YT to double check. It’s always helpful to see real parts made on these printers and know what materials are viable for them.

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Oh weird, I must have forgot to mention that (I shot the video a while back and only got to editing it now, so things were forgotten :sweat_smile:)

This was White V5. Cleaning resin out of holes is harder for more viscous resins like Tough 2K, so this trick will come in handy even more so for those.

I’ll update the video accordingly, cheers!

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Okay, this makes perfect sense. Thanks for the additional info @leonhart88

Rob

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Yes, great point. I’ve been getting better at this, and you’re right. It makes a big difference. Thanks for the reply.

Rob

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