Kresty working on Fusion Power Generator

[savagecreature]

Huh. .. . I wonder if I missed those, too. As in, I don't think I recall them in the plans anywhere. I'll be getting to that part in my build in the next few days. I'll get it straightened out.

[kresty]

Ok, I have too many things to post, but here goes.

First, I decided the Laser Cut the vanes instead of 3D Printing them.  Savage specified them @ 3mm, so that seemed like it should work.  I guess he didn't think they would CnC well?  Anyway, I also sent a couple to the lab printer just for grins.

Interestingly they both have their pros/cons.  The 3mm width was a bit tight for both, but my MEK squished them in.  

The laser cuts more of the edge, so it's a little thinner at the neck, but it's pretty hard to tell.  Interestingly, the laser has kerf so the cut is wider at the top, which makes it want to slant a little (not really an issue).  However the 3D print had a little "elephant foot" effect, so basically the same thing.

The edge of the 3D printed one was rougher, more noticeable on one than the other.

I cleaned up the corner edges of the laser cut one by running a knife along the edges.  That was way easier and faster on the laser cut ones than the 3D printed one.

The laser cut fins also each cut in under a minute.  

If I built another, I'd go with the laser cut, but either way works.  3D printed might be cleaner than some CnC's though, probably depends on the machine.

Here they are side by side:

Kresty's Fusion Reactor
3D Printed vs Laser Cut top vanes

Kresty's Fusion Reactor
3D Printed vs Laser Cut top vanes

And a test fit of the laser cut one on a 3D printed segment:

Kresty's Fusion Reactor
Laser Cut vane test fit

[kresty]

When printing the top segments I played around with the orientation.  Savage & I weren't sure what the best way to print was, though we suspected on edge would work. best.  

Here's a test print "flat" with another printed on edge below.  The "flat" one had very obvious steps in the slow curve on the bottom (I've seen that before) and was pretty unacceptable.  Print settings are the same for both.

Kresty's Fusion Reactor
Bad layers printed flat

Kresty's Fusion Reactor
Laser Cut vane test fit

[kresty]

For "my" 3D Printed segments, I added tabs under the edges to fit Savage's slot a bit.  I was worried about vertical alignment during assembly.  Additionally, I added a foot to fit on the inside of the flat ring.  My first prints had several problems with the layers slipping, so I added a temporary support (and the foot helps too).  After that they printed great.

Kresty's Fusion Reactor
Tab fittings

Kresty's Fusion Reactor
Tab and guide fittings

There are a few imperfections from the printer/print drivers (little bumps) - but they aren't really a big issue.  The original part was a cast fan rotor and probably wouldn't be perfect, so I think it'll add to the weathering effect.  I don't plan to do much cleaning before finishing.

Note that, as you know from my earlier posts, there was a scaling error on the original PDF export.  That means my top ring is a bit bigger than it should be, so I may have to adjust the position of the foot to fit as I used the wrong measurement to place it here.

[kresty]

Savage is a modeler, I'm more of a mathematician. So it bugged me that his panels were all different since, theoretically, the entire thing was symmetrical.

So, I started with one of his segments and then rotated it 11x, then cleaned up the edges so they'd fit "perfectly." Then I took off a bit for real life. I doubled up the single panels so there're 5 doubles and a single. I also added the tabs and inner foot as discussed in the last post. I know Savage was happy about his, but mine worked.

Here's the test fit. Note that I did pretty much zero cleanup here. It was a bit tight, but I figured the MEK would melt the ABS and fix that for me. The panels pretty much fit perfectly. There's a slight variation from the prints (cooling differences, different temps, different printers, whatever), but nothing worse than a normal print.

They're all different colors because when I send them to the print lab I pretty much get random colors.

Kresty's Fusion Reactor
Top test fit

Kresty's Fusion Reactor
Top test fit

I was particularly impressed with the fit in the bottom ring. I mean, I did the measurements for the foot bit, but I didn't really expect it to work perfectly on the first try - yet it pretty much did exactly what it was supposed to!

Note that, as mentioned in the previous post, my ring is a hair too large due to the original PDF export error. The plans have been fixed. The new inner diameter is 169mm, the too big one was 170mm. So I probably should adjust the parts I uploaded to fit the corrected laser cutting plans. Also it fit pretty tight with mine, a CnC with less kerf may be even tighter. I'd expected maybe to need to sand the inside of the ring a little, but it worked for me.

[kresty]

I also did a test fit for most of the base parts.  This is the bit that I got tripped up on when I tried to start assembling last spring.  Now everything fits pretty much perfectly!  Only one of Savage's sheets (the "grill" rings and 8 supports) were really far off, so the others are pretty close so I only had to recut the parts on that sheet.  Fortunately it was only 3 kinds of parts, so that wasn't too bad.  Unfortunately I'd spread them across several sheets so I needed different arrangements for the recut.

Note that one thing I did was tried to cut as many "rings" as I could in one part.  Then I put the supports and vanes in the middle of those rings so I wouldn't waste too much space.  (19 of the grill rings, the top grill ring, and "H1" are still split though).  That made test fitting the bottom pretty smooth:

Kresty's Fusion Reactor
Test fit of base

The tabs of the grill were really tight in the rounded part, I guess the kerf on those slots isn't as bad as I'd feared.

[kresty]

Huh. .. .  I wonder if I missed those, too. As in, I don't think I recall them in the plans anywhere. I'll be getting to that part in my build in the next few days. I'll get it straightened out.

Let me know the dimensions and I'll squeeze them into my laser cut plans.

[kresty]

And thanks again Savage for creating the plans! It's been great beta testing them!

[kresty]

Well, I decided to label the little squares on the E band E² (E-squared, get it?  Like they're squares on E - nevermind).

(Photo was updated, but it might take a bit to refresh).

I wasn't sure if it was 1/16" or 1/8" so I cut it out of 1/8" and then 1/16" acrylic ('cause that was in the bin by the laser cutter).  I'll see which looks bettererest when I get there.

[kresty]

Savage, do you thing that we really need 2 of the "G" bands? Looks OK to me with one & seems strong enough. (Needed 2 C bands to reach the lip of ring D).

You said that the E Bands would be reasonably easy to file at an angle. That seems to be true, but you neglected to mention that interested felines might spy the dangling end from across the room and come to "assist" with the filing...