Iterative rapid prototyping.
So, I've been printing bits of this helmet pretty much since the last post. What follows is the process of getting it right:
Front middle section of dome and brow ridge -- original scale:
This one was too snug, and I had concerns about my ears chafing
110% of original scale, front middle section of dome and brow ridge:
Room for my ears, reasonable visor location (based on how I imagine the top dome slice fitting)
Printed the back section (Also 110%) to check for glasses clearance:
Yup, looks good to go for glasses!
The rest of the pics that follow are with the above 2 pieces -- 110% with the top dome slice also 110% -- I don't have a pic of just the dome and brow, but later pics will confirm the visor consistently sits so I can see
Let the CHEEK BATTLE... BEGIN!!!
So in retrospect, this first cheek print was kind of foolish. I scaled the cheeks up to 110% (naturally) to fit the dome. This wound up taking a cheek that I alread knew was bordering on too long and adding a little over an inch to it. Result:
Holy crap-- way too long! (I mean, like, if I want to look down, like EVER) -- not a shocking result, in retrospect.
Up till now, I'd been doing my scaling in my slicer -- time to go back to fusion. There, I scaled everything up to 110% (uniform scaling) my percentages hereafter, are based on that 110% I made myself a couple of size options with the plan of just printing cheeks until I figured out which size was going to work --
but here's the trick. The front to back and side to side measurements for the other pieces were already correct. If I'd used uniform scaling, I would have gotten pieces that were the right height, but too small along x and y to fit the dome. So I turned off uniform scaling and only made the scaling adjustments to the Z axis -- this is why it pays to model your design in relation to the planes in Fusion 360.
85% (of 110%) - Cheek: -- note -- the back ring doesn't get reprinted until I settle on the actual cheek size. (110% cheek included for comparison)
Better, but still concerned about hitting my shoulders, and one of the things I don't like about my current bucket is that I didn't spend enough time getting THIS part of the fit right, so --
70% (of 110%) - Cheek (85% included for comparison)
Looks like we have a winner, needed to print 70% back ring to confirm
70% Cheek, 70% Back ring with Keyslots:
Winner! -- Printed the other cheek, but I don't have taped pics of that.
The other thing I had to fix fromt he original is that I modeled in some alignment tabs -- my design didn't work out, and the tabs actually make the inside of the helmet uncomfortable. So I shaved them off the model, and the front part of the dome and brow, sans tabs is currently printing. After that, I'll reprint the back half and then I can do full mockup.
And now, a comparison of how the design started, and where it ended up:
Orginal Scale
110% dome parts, 70% (of 110%) rest of the bucket
