Solidworks, internal passages converted to solids

[petertha]

Does anyone have a good workflow for this kind of problem: I have a solid or assembly of parts. It has some combination of internal holes, passages, clearances etc. I want to kind of reverse the process & gain access to the internal structure as a solid by hiding/subtracting/eliminating the bulk material around it.

Here is a simple example just demonstrating 2 intersecting countersunk holes. I want the 'inside stuff'. I thought there was a way to explode the solid into surface elements & then rebuild the internals that way. But Im not that experienced with surfacing yet.

 

[Tin Falcon]

I am no expert on solid works . never touched the stuff but from what I have heard it is quite similar to Aibre CAD.

fist sounds like you are looking to create a sectional view.
In Alibre just create your model then select create 3D sectional view then select your cutting plane.
I am new to alibre and stubleed on i seems quite easy once you get a hang of it.
is this what you are trying to do ?

Hope this helps. if not there are experienced SW users here that I am sure can help.
Tin

 

[petertha]

...sounds like you are looking to create a sectional view...

I can handle SW sectional views ok. What Im trying to do is kind of reverse the solid. I dont want the external block part anymore, I want the resultant internal cavity part (hilighted in red) that came about by various features or operations imposed on it.

I know in typical mold design, one starts with the finished part, then superimpose the mold block, then subtract the two & you are left with a female cavity type mold. In my particular situation, it kind of starts with the block (as assembly of parts actually actually) & I would like to treat the 'resultant' cavity(s) bewteen these parts as a solid. So I just posted this illustration as a simple example to help visualize.

When I worked in Rhino, you could (what they called) 'explode' a watertight surface (=solid) & then get access to each of the connected surface features & rebuild it into something different from there. I though SW had a similar command, but I'm not sure.

 

[jor2daje]

I believe you could use convert entities at all the critical points to create circles that you could sweep using the section view as a guide curve, though Im not sure that's much easier than just redrawing the part from the dimensions.

 

[Tin Falcon]

Do you mean like this ?

Just a test doodle on Alibre . I extruded a couple of circles at 90 degrees then did a sweep boss of a few triangles and a rectangle.
to me not a big deal to just draw it but I did spend 6 years making patterns and molds for Yachts so I am used to thinking positive and negative shapes and manipulating shapes in my head.
Tin

 

[Tin Falcon]

Or you can model as a tube and do a sectional view or not. just experimneting.

Tin

 

[petertha]

I dont want the external block part anymore, I want the resultant internal cavity part (hilighted in red) that came about by various features or operations imposed on it.

I think my example solid picture is actually confusing matters, so I'll try with again with better words. I too can replicate a simple internal cavity shape like the 2 intersecting holes as a standalone male solid, knowing the dimensions beforehand. But the point Im tring to make is, the cavity I might be wanting to evaluate comes as the RESULT of different featured parts, their shapes & orientations. And it would probably be quite complex to draw this cavity directly.

Example-1: Think of a multi-lobed crankshaft (solid) sitting in an open oil pan (cavity). I can model the crankshaft & oil pan as separate solid parts. I can now assemble the 2 parts. I can rotate the crank to some angular position. Now I want to make a section at an arbitrary position through the crankshaft & determine the resultant cavity volume (the oil volume if that helps illustrate).

Example-2: here is a picture showing typical internals of an engine's side induction ports. I can easily model every single component part, the cylinder (with inlet ports geometry, the crankcase (with side pocket flow channels), the head (combustion chamber ceiling shape)... etc. Similarly, I can assemble all these parts together as they are orientated in real life. Now what would be cool to see is the RESULTANT cavity representing the induction flow path. Not just to visualize, but to be able to treat it as a solid element & therefore use the many solid tools available to solids analyisis.

Hopefully this illustrates the problem better - its relatively easy to make a set of parts in an assemly, but its potentially quite difficult to generate the internal cavity from the ground up. Thats kind of what I'm driving at.

 

[Tin Falcon]

Sorry for any misunderstanding. I will turn you over to the experienced SW users maybe they can answer your question.
Tin

 

[doc1955]

I'm not sure with solid works but I think NX is close to the same and how I would do it is create a solid block encompassing the solid you would like to end up with and use a intersect command. That would be the simplest in my opinion. In cad you will find there are many ways to end up with the same thing some just easier then others.

 

[mu38&Bg#]

Right you, create an assembly using the part you want cores for. Insert a new part and in the case of your example create a solid to encapsulate the entire part. Now, use the mold cavity tool to remove the parts you don't want by selecting the first part.

If you have other areas that are left over in the case of a complicated part, use the delete body tool to remove them.

If the shape is simple like in your example above I've also just converted sketch or other lines to create a solid to make the cavity part.

The below took a couple minutes. There was a large amount of extraneous junk but it was easily removed with one cut.

Greg

 

[kf2qd]

Create another solid rectangle, move it onto the existing block and the subtract the original object from the new object. What is left should be the "holes" or code.