Designing a Two Stage

[nohapony]

Quick Update:

After 6 or 7 attempts I got the dimensions right so that the o-rings are making a good seal. Turns out acryIic Tubes are not exactly precision parts. I had to change the design from the rings being on the outside of the cylinder to the inside as it was not possible to attach the top/bottom with the required o-ring compression.
I could successfully pressure test some test parts to confirm they hold a vacuum. Next step is to print the final parts

[Dink]

...
. Next step is to print the final parts

Awesome. It is interesting how acrylic, and some of the glass containers, are within a reasonable tolerance of the states dimensions.

Looking forward to your next post, and hopefully some images soon.

[nohapony]

First piece printed, partly finished and tested. I'm not happy with the surface finish at that stage. It still needs more sanding/smoothing. But it's functional.

[nohapony]

And.... done!

At least the first version. I ran out of blue filament mid print and needed to swap to some bright orange

[Bigball12]

Wow

[cma_throw]

And.... done!

At least the first version. I ran out of blue filament mid print and needed to swap to some bright orange

Looks great! I like the orange flair.

Can I ask your source for the stainless steel fittings? I've been thinking of making my own DIY tube.

[nohapony]

Can I ask your source for the stainless steel fittings? I've been thinking of making my own DIY tube.

Those are PC water cooling fittings. I think I bought Alphacool ones because they were the cheapest. Easy to get: Amazon, eBay, AliExpress, whatever. If you have a well stocked PC parts shops nearby maybe they also will have some

[TinyMe]

Looks really good

[Dink]

Agreed, the progress is great. Looking forward to it being posted on you GitHub. Going to have to set up the 3d printer again.

[nohapony]

Agreed, the progress is great. Looking forward to it being posted on you GitHub. Going to have to set up the 3d printer again.

I-'m actually very unsure if I should publish it. My fear is that if someone else prints it, it wouldn't work. The parts need to fit quite precise to seal. This was a bit of a challenge. The tube in the last picture should have a 150mm outer diameter and wall thickness of 3mm. In reality it's something like 151mm and thickness between 3.1 to 3.2mm. Then there is also the printer accuracy and print settings which adds extra tolerances.

My guess is the design could maybe tolerate +/-0.1mm deviation and still seal. Assuming the 151mm tube I got is on the upper end of the manufacturer's tolerance window that would mean +/-0.5mm for the tube alone.

My feeling is that the model dimension are pretty much just working for the exact tubes I bought and the printer I printed it on. I'm not even convinced that if I printed it on my other printer (which is broken currently) that it would fit and make a seal. By publishing my fear is it would just end up in frustration for people as it just won't work.

If you are willing to try it out I could sent you a test file to see if you have any luck to get it working.

[MasonBall]

I use an LApump 2 stage 4x6x10 and I really like the offset entrance even though everything is 90°. The overhang is really comfortable and I like the corsetting effect it has. I have a 4" stainless steel ring I like to wear, and it stays in place better when I use the 2 stage instead of the 4"straight tube.

[Dink]

If you are willing to try it out I could sent you a test file to see if you have any luck to get it working.

I'd be happy to try it out. Can you send the files via private message or via a link in a message?

Thanks.

[nohapony]

I currently trying a split design. After a few different design approaches I settled on this one. The first printed parts are leaky, but not where I expected them to be. I made some adjustments and printing new parts. Fingers crossed this maybe could work.

[Pumping Now]

A lot of fiddly bits to put on & remove...
How about ledges & Binder Clips?

[cma_throw]

The first printed parts are leaky, but not where I expected them to be.

Have you considered switching to an electric pump? That might help with the leaking. Breast pumps are easily modified for our needs (search the forum for directions).

This guy also made a break apart cylinder and he noted that an electric pump is essential: viewtopic.php?p=291279&hilit=zylinder#p291279