Model Engine Maker

Supporting => Additive Machining => Topic started by: BillTodd on November 13, 2018, 09:07:03 AM

Title: Tower Spherical Engine (3d print project)
Post by: BillTodd on November 13, 2018, 09:07:03 AM
This started a decade or more ago when I animated the engine for Doug's museum of retrotech  (http://www.douglas-self.com/MUSEUM/POWER/tower/tower.htm). I have been wanting to build a physical model ever since.

The bulk of the engine will be 3d printed , mainly because making the spherical parts would require special tooling that I don't have. The other bits are all available on ebay ,so it should be possible for others to make the model .

The model engine is designed to run from a vacuum cleaner , to avoid the need to contain any serious pressure.

I started converting an old engraver project (itself made from an old plotter project) into a 3d printer (https://madmodder.net/index.php/topic,11263.msg152896.html#new) a few years ago and I'm still have some problems getting flat prints. On top of that an update has buggered my copy of the Marlin 3d print software (any Marlin/Arduino experts here?) and now it will not compile.


.
Title: Re: Tower Spherical Engine (3d print project)
Post by: AOG on November 13, 2018, 02:12:35 PM
That’s a very interesting design. I will be following along. On the Marlin issue, most of the time I have problems compiling marlin is because I forgot to include the U8Glib library that runs the display. For your flat print issues, turn on Manual mesh leveling in Marlin and use a raft. There is a tutorial here  https://www.printedsolid.com/blogs/news/installing-marlin-1-1-6-on-your-cr-10s-with-mesh-bed-leveling (https://www.printedsolid.com/blogs/news/installing-marlin-1-1-6-on-your-cr-10s-with-mesh-bed-leveling). It’s intended for the Creality CR-10 but it may still be worth a look.

Tony
Title: Re: Tower Spherical Engine (3d print project)
Post by: BillTodd on November 15, 2018, 10:15:04 PM
Thanks Tony.

I managed to get Marlin compiling again (just a matter of deleting the old U8lib and reinstalling).

I'll have a look at that tutorial,  my bed is reasonable level but the problem I've been having is warping due to the bed heater not working (actually it does work but somehow trips the power o/p off at random!)

I'm now updating my model to add some extra clearance based on the prints I've made.

Bill
Title: Re: Tower Spherical Engine (3d print project)
Post by: BillTodd on November 21, 2018, 08:30:37 PM
Well printer is up and running again. Currently 3 hours into a 12 hour print of the base unit

update in 9 hours or so
Title: Re: Tower Spherical Engine (3d print project)
Post by: ddmckee54 on November 21, 2018, 08:52:35 PM
Bill:

Just for giggles and grins, what sort of extra clearance have you found that you need to add?

Don
Title: Re: Tower Spherical Engine (3d print project)
Post by: BillTodd on November 21, 2018, 09:10:59 PM
on the central jointed parts I've given it 0.4 mm (0.2 on each part) result is a bit tight and requires some fitting.

I'm not too worried about clearance or leakage as the vaccum cleaner power will happily deal with the extra flow. It'll be important that the clear plastic sphere is not scratched by the spinning bit.

I intend to make a couple of complete engines before releasing the stl files , somanone should be zble to build it without the need for filing and sanding.

Bill
Title: Re: Tower Spherical Engine (3d print project)
Post by: BillTodd on November 22, 2018, 08:38:33 AM
Well that worked better than expected :-)

Title: Re: Tower Spherical Engine (3d print project)
Post by: Admiral_dk on November 22, 2018, 11:13:29 AM
Looks fine so far  :ThumbsUp:

Did you print the sphere too ?
Title: Re: Tower Spherical Engine (3d print project)
Post by: BillTodd on November 22, 2018, 07:01:39 PM
Looks fine so far  :ThumbsUp:

Did you print the sphere too ?

The sphere is an ebay item - christmas decoration I believe


Anyway...

The rotor fits sort of - could do with a little extra end float (bearing placement is a bit tight)

Ebay 608 bearing are serious crap - I wondered why they were loose on my 8mm shafts (thought I'd pick up some 5/16" rod instead) the 8mm ID is actually 8.15 !!
Title: Re: Tower Spherical Engine (3d print project)
Post by: BillTodd on November 24, 2018, 01:08:18 PM
it spins!

https://www.youtube.com/watch?v=CbxUUHdj7V0
Title: Re: Tower Spherical Engine (3d print project)
Post by: sco on November 24, 2018, 05:04:32 PM
Very interesting engine Bill and clever work with the 3d printer to realise it.

Simon.
Title: Re: Tower Spherical Engine (3d print project)
Post by: KB on November 24, 2018, 06:54:19 PM
What a neat design!
Title: Re: Tower Spherical Engine (3d print project)
Post by: BillTodd on November 25, 2018, 02:54:19 PM
It works....

https://www.youtube.com/watch?v=2e0P1ICaYjo

Not the most efficient model ever created (800w input for almost zero out)  but  we have a gas pressure engine :-)


ATM there's probably too much clearance between the sphere and the valves so air is leaking around the wedge shaped Rotors reducing the pressure across the yellow separator/piston.

And , for some reason it'll just jam after a while and then clear itself

 
Title: Re: Tower Spherical Engine (3d print project)
Post by: Jo on November 25, 2018, 04:19:17 PM
8) Nice.

Jo
Title: Re: Tower Spherical Engine (3d print project)
Post by: Ye-Ole Steam Dude on November 25, 2018, 05:43:03 PM
Hello Bill,

Most unusual and interesting, but neat to watch it run.

Have a great day,
Thomas
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