Designing a Small Dust Cyclone for a 3D Print?

I’m using Sketchup to try and model a cyclone with a 4" inlet and outlet for use with a woodshop dust collector.

I’m having some issues getting a smaller version of it (Using scaling in the 3D print software) getting it to print though.

What are some of the things that I’m doing wrong? I noticed that the lines left over from some of the merges between different objects (When I was trying to merge the pipe with the body of the cyclone are rather hard to remove and require selecting like 30+ line segments)

Also, “orient faces” seems to want to make the inside face the outside face.


Custom Cyclone.skp (216.1 KB)

There are quite a number of problems with your model. Faces in SketchUp have no thickness and a lot of your model is built that way. You can see that in the top section.

That’s because the walls of your cyclone have no thickness.

The way you’re grouping geometry isn’t correct either.

How much of it are you intending to print? Just the inlet pipe or the whole cyclone housing?

More questions. How did you determine the shape of the inlet pipe? Is it shaped the way you want it?

I’ve redrawn your model as two parts, the cone and the top section. Each is solid and should be printable assuming you have a large enough printer. Look at how the geometry is formed. It’s clean, the walls have thickness and there are no exposed back faces. I also noticed in your model that you’ve got circles drawn off axis which is creating a mess, especially at the top of the cone.
Custom Cyclone.skp (219.4 KB)

I watched a tutorial on YT that said that wall thickness wasn’t necessary for printing. I guess I’ll have to add wall thickness from now on.

How did you add the wall thickness? Using the offset tool?

Probably in pieces. I don’t think I can get access to a printer large enough to do the entire thing (Stony Brook University has a large number of printers. I’ve contacted the person who manages the facility because I know they have larger printers, although I don’t know their dimensions). If I have to print it in pieces, I’m not sure how I could join them.

I made the pipe by creating a helix (Using an extension), putting a circle on the end of it and using the follow me tool to extrude it. I then merged the inlet pipe (The one on the side) with the upper half using merge with selection. I tried creating a box on the side of the pipe to hold it firmly so it couldn’t be easily sheared off.

The size of the pipes are both grabbed from my bandsaw 4" dust hose fitting size: (Inner Radius: 50mm Outer Radius: 45.85mm). The pipe is shaped (more or less) how I want it. I was studying other ideas like from the Dust Deputy (

Honestly, I would love to know how you made the modifications you made. I was kind of scratching my head as to where to go, and in a certain sense still am. It looks like using Sketchup for 3D print jobs is somewhat different from room design or woodworking, but I’m always happy to learn a new skill if it’s valuable :slight_smile:

At least in SketchUpyou do need wall thickness. At least for a hollow structure. For thicker things that would get infill, you don’t need to model the infill. It may be that’s what the video was referring to. The surfaces in your model represent the interface between the printing material and the surround air.

No. I drew cross sections of the parts and a circle for a path and used Follow Me. I didn’t use Joint Push/Pull as Forestr alleges.

I’m sure the wall thickness is probably not enough and the flange at the bottom could use some details. There also needs to be some method of keeping the two pieces aligned. At the point I was modeling it, I was mostly concerned about showing the external shape and what you need to make it solid for printing.

It’s nice to have access to a large printer. If you can’t print the parts in one piece, you’ll need to give some consideration to how to divide it up so you can assemble it and make it air tight and strong enough to deal with the pressure difference between inside and outside.

To be honest, I’m not sure that 3D printing is the right way to go about making this particular thing. If you can’t print the major parts in single pieces, you’ll need to design the individual parts so they can all be made to accurately fit together so seams can be closed up. The inside surfaces will need to be quite smooth or it’ll trap dust reducing efficiency. The outside surfaces will also need to be smooth or they will trap airborne dust and be hard to clean. (Your cyclone will become camouflaged and you won’t be able to find it. :smiley: ) Blow molding or injection molding are probably better ways of making the thing. I think cyclones like the Dust Deputy are injection molded and the top is ultrasonically bonded to the cone.

That’s a good method. I used your pipe and joined it to the upper part using Solid Shell since it was solid and my lid was solid. It really should be modeled using more segments for the circles so it’s closer to round.

The box was good thinking although I believe I would just add some ribs on the outside for that.

Have you looked at the information Bill Pentz has produced on cyclone design? A lot of good information.

Hopefully my explanation above is enough. You managed to get that pipe made so I think you can do the rest of what I did.

Modeling for 3D printing adds the need to create manifold shapes. In simple terms that requires that every edge be shared by exactly two faces. No more and no less. The majority of the modeling I do is for woodworking projects, not 3D printing, but I make it a practice to have only solid components in my furniture models, too. It makes for clean models and makes the components easier to work with when inevitable modifications come along.