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Fusor Mk. II

Posted: Sat Dec 05, 2015 5:45 pm
by Scott Moroch
Over the next several months Jack and I will be upgrading our fusor to a 9" ID spherical chamber. We hope to detail our efforts on this thread. We had a lot of success in our smaller KF 50 fusor, however certain aspects of the design made it very difficult to collect data and sustain stable fusion. After reaching out to Huntington Mechanical Labs, they offered to donate a custom-made spherical chamber. This chamber is going to be used for a variety of different experiments, including ion sources.

I have attached images of the CAD designs of our chamber and hopefully within the next 1-2 months I will add additional pictures to this thread detailing our efforts. Certain components such as our vacuum system and high voltage power supply will remain the same, however we plan to add a mass flow controller for better control of gas flow in the chamber.

Scott Moroch

Re: Fusor Mk. II

Posted: Sun Dec 06, 2015 10:57 pm
by Andrew Robinson
Nice job Scott. Little concerned about some of your CAD. some of your ports are awfully close to your chamber. Remember, with CAD, it's really important to account for all parts in your assembly, not just the main pieces. Add everything you can which will help you spot problems before you spend a lot of money. In addition, it is also even more important to be sure your chamber can be assembled mechanically. Its easy to make these mistakes in CAD. This is why for example, some batteries in cars are very difficult to replace, or in a few hilarious oops, impossible to remove without disassembling part of the car. Visit a hardware supplier such as McMaster-Carr and download the required CAD hardware for your assembly. Make sure you have enough clearance for everything and if possible use your softwares built in motion analysis for bolt placements (if available).

Re: Fusor Mk. II

Posted: Sun Dec 06, 2015 11:14 pm
by Scott Moroch
Andrew,

Thanks for the response and your insight. This is the final design as far as port placement however the person at the company is going to adjust the CAD to have all ports thru-hole and mounted with suffecient clearance to allow enough room for me to easily tighten the bolt and nut. He told me that this is something incredibly common and is done all of the time for customers of Huntington. All in all the chamber is:

7-2.75" ports (for gas line, TC gauge, ion gauge, high voltage feedthrough)
2-4.5" ports (one for a viewport and one to be blanked off)
1-1.33" port
1-6" port

The ports have been arranged in such a way to be used for a variety of experiments. 8 of the ports are placed on a diagonal for ion source experimentation.

Scott Moroch

Re: Fusor Mk. II

Posted: Sun Dec 06, 2015 11:28 pm
by Andrew Robinson
Glad to hear you have someone watching out. Not everyone is that attentive and others will just build to specification. Food for thought in the future. Looks like you guys have a bright CAD future too. Cheers

Re: Fusor Mk. II

Posted: Mon Dec 07, 2015 7:01 pm
by Richard Hull
Ports real close to the chamber are usually tapped Conflats. I have zero clearance on my HV conflat. I actually turned the back face to make the weldment lip for insertion to the sphere. All planned, of course. If you do all your own machine work and welding you can do stuff like this at zero dollars out of pocket.

In my design FAQs related to fusor construction, I advise about careful pre-design test fitting of components prior to palcement and welding.

Richard Hull

Re: Fusor Mk. II

Posted: Mon Dec 07, 2015 8:30 pm
by Andrew Robinson
Very true, I had considered that, but opted not to update post. Even with tapped flanges, still a god idea to get everything modeled properly. Bolts could be too long. Still applies in either case. I have been working up a nice FAQ on CAD based design, pros, cons, etc for several months now. Need to finish it off and get it posted.

Re: Fusor Mk. II

Posted: Tue Dec 08, 2015 5:37 pm
by John Futter
Tapped flanges are a disaster in waiting especially for hobbyists.
It is unlikely that the hobbyist will buy the correct silver plated SS bolts that reduce galling / thread pickup
Unless absolutely necessary all flanges should be through hole to avoid this problem.
Having had to have a snapped bolt spark eroded out and a 6"CF cube re-machined to fit a helicoil for that one bolt is time consuming and expensive

Re: Fusor Mk. II

Posted: Tue Dec 08, 2015 5:46 pm
by Andrew Robinson
Yes I agree entirely. I hate the idea of tapped flanges. The chamber is the last place I would want to use them too. Not as easy of a replacement/fix as other components. Non issue here ofcourse since Scott mentioned that the CAD does not reflect the final product in terms port clearance.

Re: Fusor Mk. II

Posted: Mon Feb 08, 2016 10:45 pm
by Scott Moroch
I have attached another rendering the chamber that was done at the company for me this time. As I work on my CAD skills both in school and at home I hope to incorporate more CAD renderings into my projects. More progress on Fusor Mk. II will come within the next couple of months. Jack and I hope to have the system up and running in the Spring.

Also, please note, the ports do appear close to the chamber however this has been changed. All ports will be mounted as thru-hole and further from the chamber.
Scott Moroch

Re: Fusor Mk. II

Posted: Sat Apr 16, 2016 5:03 am
by Scott Moroch
Jack and I are continuing to make progress on our Fusor Mk. II design. Recently we obtained a BTI bubble detector which we intend to use for more accurate neutron measurements. The company finished the manufacturing drawings for the chamber and I have attached images of the most recent CAD renderings. In addition, this weekend Jack will be attending the MIT flea market where we hope he will find/ buy all of the final conflat components we need for our chamber.

For this fusor we are currently working on designing and constructing a reactor chassis out of aluminum extrusions 20mm by 20mm. The goal of building this chassis to have one complete, unified and compact containment for the fusor. I hope to post some designs on this shortly. The extrusions themselves will be purchased from Misumi: http://us.misumi-ec.com/vona2/detail/11 ... 0-1524-RTP

The brackets and connectors will be fabricated on a CNC machine in order to reduce cost.

Scott Moroch