3 Years ago if you’d ask me what I was going to do with my 3D printer I would have said, “I haven’t got a clue, they just look really cool”. I think the first human to invent the wheel wondered the same thing…..
It’s difficult to understate how it’s changing lives and the way design is approached. But a word of caution. Printers are evil, the devils instruments. They are blasphemy. When I design for plastics I go to great care concerning draft for tooling, will it come out the mould correctly…. Are wall thicknesses correct, will I get sink, bloom etc…etc.. the list of plastic moulding pitfalls is ENDLESS!! Where are the feed gates. OMG undercut, the CAD is wrong it’s gone to tooling…this mistake will cost $$$ to fix. Well all that design consideration has basically evaporated; all those hard learned rules can be thrown out the window. I tell you now, 3D printers are the bad boyfriend you never want your daughter to meet.
Unfortunately I’ve succumbed, turned to the dark side of printing. If you’ve not already realised it, you can now create geometries and impossibilities only previously conceived in the mind of an insomniac. Features within hidden cavities, honeycombed structure whose intricate innards opens up new worlds of hitherto unseen weight to strength ratios. It really is miraculous what you can do with a 3D printer.
Gushing ramble over, let’s get down to business with some very simple prints. If there’s one thing offered up by 3D printing it’s cheap, fast reliable jigs for making and setting up the scope. I want the mirror cell bolts accurately drilled to the OTA on every facet identically; no problem, a small drill guide.
Need to set your secondary centrally in the cell. This Jig, you just snip away after, makes it a cinch. (I do my secondary offsets from the secondary upper cage/vanes for the astute here! For an F3.3 12in scope that’s 5.6mm away and down.). The tabs UNDERNEATH the edge lip of the lower secondary cell, made transparent here, allow the mirror to stand 1.5mm off the surface of the edge whilst applying silicon. Th old method was a matchstick.
Or what about a secondary cell slider to work out where the secondary needs to be on the OTA. Not having an exact F.L. and needing to introduce a coma corrector has complicated matters. Don’t get too excited about the radioactive puke colour spider vanes. Both those and the side vertical sliders are temporary!! Only a small hole will be drilled out the side of the OTA for a quick star test with the coma corrector inline. The final vanes are 0.5mm Aluminium acid etch primed and coated BLK3.0
Another word of caution. I’ll do a separate blog on printer techniques and materials but never get too carried away with what you can create strength-wise. At the end of the day, it’s still a bit of plastic. There’s a time and a place so I wouldn’t go printing your equatorial drive shaft any time soon (some smart ass will print their equatorial drive shaft next week and put a 25in reflector on the end of it).
Well anyway the point is, a paradigm shift is required when thinking about how to use a 3D printer. That’s not the advertisers hyperbolic usage of the word paradigm by the way, I really do mean it in it’s truest sense and I can’t stress that more.
A very exiting time indeed, even if we are stuck in our houses.