Adding hole for water removal after PVA Dissolve

[HuszakM 0]

Hi there:

I print mostly organic, detailed models and therefore we use many PVA support. After that, because of the big size of the models, the dissolving process takes hours. During that, the modell usually gets filled with water which is hard to remove from inside the model.

 

What I would like to achieve, is to add a hole, before printing, so I don't have to drill the model.

 

For example on the picture, I want to create a "booelan", so I can see "inside" where there's infill. 

Do you think it's possible without editing G codes? 

Thank you!

 

[MariMakes 193]

Hey @HuszakM

 

Welcome to the Ultimaker Community 🎉

 

You can do this in Ultimaker Cura with mesh modifiers!
No changes in Gcode required. 😄

 

Just add a mesh in the correct position with the volume you want to remove and define the following settings:

1. Mesh Type Modify for setting overlaps
2. Define a Cutting Mesh
3. Select the settings:
   1. Wall Line Count
   2. Top Layers
   3. Bottom Layers
   4. Infill Density 
4. Set all the values to 0

I hope this helps 👼
Can you let us know if this is what you are looking for? 
 

[HuszakM 0]

This is exactly what I was looking for! But this is what happens with me:

 

Any suggestions?

 

Edited October 4, 2022 by HuszakM

[gr5 2,099]

Just to clarify - when you soak your parts in water, sometimes water gets inside the part where it shouldn't be possible (but there are often imperfections/holes.  And that water is difficult to get out again.  In addition to what mari suggests, I recommend you use an infill pattern that allows water to drain okay.  Most infill patterns create many separate internal volumes that are not connected.  You want a pattern that lets water/air travel around inside the part.  I recommend: gyroid

 

[gr5 2,099]

@MariMakes - I can't get it to work either.  We are doing something wrong.  I tried both cura 4.12 and 5.0:

 

[MariMakes 193]

Sorry! I made a mistake. 😖 

I did not mean to deceive you. 
By accident, I already chose a hollow model to show my plan.

But depending on the model, you can your model hollow in Cura with a similar trick like I did here:

Mari_HollowRobot.3mf

1. Duplicate the model
2. Make the models overlap
3. Disabled Drop to buildplate, in Preferences, Configure Cura
4. Make one of the models slightly smaller in the Z direction
5. Change the Horizontal expansion into a negative value for the X and Y direction
6. Change the per object settings as mentioned above
7. Add a mesh to function as a hole with the settings mentioned before
8. Make the two cutting meshes overlap

 

I'm hoping that this trick is still relevant for your purposes.
It has become more trickier and less universal now. 

[gr5 2,099]

You *can* remove the bottom layer of your model by setting "bottom layers" to zero but that will probably mess up your artistic model in dozens of places.  For example on the underside of the chin of a person's head - the infill would be exposed (image is looking up from below the build plate)

 

[gr5 2,099]

I think you are just going to have to go with gyroid and drill a hole 😞

 

[gr5 2,099]

Here's the basic problem.  Both meshes have walls (and top and bottom).  As you can see below the modifier I put 2 walls and you can see the red and green inner wall.  The purple shows the model has 3 walls and you can see the 1 red plus 2 green walls.  Setting "wall line count" to zero only removers the "blue" indicated walls.  The same issue occurs with top/bottom surfaces.   So...  I think you need a drill.

 

(click image below once for the full scale view)

 

 

[Dim3nsioneer 557]

3 hours ago, gr5 said:

I think you are just going to have to go with gyroid and drill a hole 😞

 

Yes to the first part and no to the second part. 😉

 

3 hours ago, gr5 said:

by setting "bottom layers" to zero

You almost had it 😃

 

Use gyroid infill and set 'Initial Bottom Layers" to zero.

Now, we can start with the "what if"s... 😆