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"Cool" pictures

Posted: Wed May 10, 2017 6:46 pm
by Andrew Robinson
Unfortunately, I don't get that many chances to share our work with you guys due to NDA and other legal shenanigans, but I finally have some "cool" fusor only related pictures that they will let me share. Machining pictures to follow. Enjoy!
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0.375" G11 Garolite (Phenolic) blank ready to be machined. This blank will ultimately be cut out for use as a thermal barrier in a custom LN2 trap.
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Custom modular fixture plate used for several parts. Notice how the fixture is actually split into three identical modular plates. The plates themselves are machined separately first, then stacked next to each other for however many are necessary based on the final part required, and then a custom fixture program is run on top of the joined plates for the part in question. In this instance, several drilled and tapped holes are added to the fixture as well as an engraved outline to help with initial blank positioning, and finally two X adjustable work holding clamps. This method facilitates the reuse of fixtures for multiple parts.
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Close up of custom fixture work holding.
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G11 0.375" blank loaded onto custom fixture to be drilled and reamed in preparation for actual part program. Notice how the blank is shifted up slightly above the pins for initial drilling. The finished blank will then be moved down onto pins for actual machining.
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Close up view of precision locating pins. These pins are .2500" and pressed into .2495" reamed holes in fixture. The part is them reamed to .2510" to slip over the locating pins.
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G54 of blank, bolted down ready to run actual program.
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G54 (Side 1) of the part. Part aligned with locating pins and 1/4" carbide chamfer tool run. It is critically important to cut G11 with carbide! All other tools will just burn up in the material almost instantly!
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LN2 thermal barrier shortly after drop out. We have dubbed this part the "toilet seat". :)
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Another view of the toilet seat after drop out.

Re: "Cool" pictures

Posted: Wed May 10, 2017 7:16 pm
by Andrew Robinson
More pictures now showing the machining of the aluminum support structures and some initial installation tests.
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Fresh fixture blanks have been bolted to table and are being prepped to accept work holding clamps and other necessary features for part machining process. The process is initially very labor intensive. 1. Modular blanks must be programmed and machined. 2. Fixture programs must programmed and machine and must be thought out logistically to accommodate both blank creation and actual part machining. 3. Blanks must be programmed and machined. 4. Actual parts can then finally be programmed and machined from the blanks. Very time consuming process, but once you have parts such as modular fixture plates done and several stock piled, it makes the process a little easier.
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View of fixture ready to accept support structure blank. Note the positioning outline again that was used in the previous step to produce the blank using the work holding clamps (Not visible here).
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Support structure blank bolted down to fixture, ready to machine.
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Close up of modular fixture corner. Each modular fixture not only gets an individual part number which is indexed in our database, but then each combined fixture gets an "F" designated part number engraved somewhere on the fixture to associate it with the part it is designed for. In addition, all blanks, tooling, raw materials, final parts are associated using similar part numbering system and cataloged digitally so everything can be tracked and pulled back off the shelf at a later date if revisions are needed or for other tracking reasons. Every part number can be broken down into categories such as revision (major, minor, fix), assembly, sub assembly, part increment, manufacture, origin, etc. Everything is tracked digitally in a custom built Atomiklan inventory system for our research team.
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Close up of mid G55 milling procedure. Carbide 0.375" endmill just finished cleaning up the Ti coated roughing mills handy work. Surface is nice and smooth now.
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Closer view of mid G55 process.
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Mid G55 milling. The back side of this blank has already been cut and located on pins, this time in center of part instead of edges.
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Aftermath of modular fixture plate from cutting one corner. We probably cut a little too deep into this fixture haha. :)
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Image of first joining plate to come off machine. Notice this one has already been test fit once on the assembly due to the grease marks from 80/20 bolts. Nasty black oxide bolts...
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Side view of diff pump.
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Top view of assembly giving a better view of dual purpose 80/20 corner joining plates and diff stack supports.
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Room temp view from underside of assembly. Notice several parts still missing from this assembly including bolt sleeves.
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View from outside assembly with mobile LN2 tank in view. This was one of the best things we ever built! Makes moving around small amounts of LN2 so much easier. HIGHLY recommend these small pressurized dewars. You can see the build process for that tank here: http://www.fusor.net/board/viewtopic.php?f=18&t=10643&hilit=Nitrogen
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Initial visual testing of thermal barrier. So far the results are pretty conclusive. Supports are maintaining room temperature.
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Additional view of freeze test.

Re: "Cool" pictures

Posted: Fri May 12, 2017 6:19 am
by Jerry Biehler
What kind of VMC do you have there?

For flat stuff like this I like this stuff, but whatever you are sticking down has to be able to handle 200F:

https://www.miteebite.com/products/mitee-grip/

Re: "Cool" pictures

Posted: Fri May 12, 2017 6:50 am
by Andrew Robinson
I assume by VMC, you are referring to the mill?

x1 HAAS SMM
x6 HAAS VF2
x1 HAAS VF3
x1 HAAS UMC-750

Here are a few old posts with pics

viewtopic.php?f=12&t=11190&hilit=HAAS&start=10#p74036
viewtopic.php?f=18&t=9905&hilit=+HAAS#p66590

These particular jobs were done on one of the older VF2's. Never used anything sticky before, but I have experimented with vacuum tables. Lots of trouble and can be prone to error and slippage. Bolted fixtures have always been the best solution for me. Don't usually have to worry about it though as we don't make a ton of really big parts. Most stuff fits nicely in a traditional Kurt vise.

Re: "Cool" pictures

Posted: Fri May 12, 2017 9:25 pm
by Bruce Meagher
Andrew,

Very cool indeed! Can you share the details of your custom LN2 cold trap?

Bruce

Re: "Cool" pictures

Posted: Sun May 14, 2017 9:18 pm
by Andrew Robinson
Hi Bruce,

I'll see what I can do to get some additional pictures and add a few explanations. We had to change around the design quite a bit from the original version as we were concerned about pumping efficiency. Even though everyone on the team is having a blast getting involved with vacuum tech, that is one area none of my engineers (myself included) had much experience in. As a result, we are very much so learning as we go. The trap is a dual purpose trap and baffle for the diff pump. Currently the baffle is out of the lab while we make some changes, but as soon as I get a chance, I'll collect everything in one spot and take some pictures.

Cheers,
Andrew