Wednesday, July 8, 2015

Tool Cycle

TechShop has a lot of tools. Each tool has a class which is part orientation, part safety lecture, with a short hand's-on. Each tool also has a reservation calendar.

So the trick is to get back on that machine before the lessons of the class entirely wear off. I had to bring manuals with me when I went back to the metal lathe and it took two solo sessions before I really grasped the basic principles. I've put in over a hundred hours on that tool since, and I am finally at a comfort level with simple operations.

I'm still at the manual-in-hand stage with the CNC mill -- and it has been long enough since I returned to the tool and took a solo flight that I'm still going to need a little help. But I'm at the point with that tool to begin production work.

Yesterday was the first solo at the 3d Printer. And just in time, as the class I'd taken was now two or three weeks old in my memory. Type A machine, 12x12x12 build area, and I purchased a roll of PLA downstairs as a starter set. The only problem I had was remembering that the printer driver is a browser-based software (thus no-where near the Start Menu. Or whatever Windows people call it).

I didn't have any production work ready to go, so I printed two random models; an unmodified XR-311 wheel (downloaded direct from my Shapeways shop) as a comparison check. And a simple model of Lara Croft's pendant I'd found at Thingiverse.

I documented all my settings and experimented a bit. The pendant, a flat disk 33mm in diameter (according to the software, 2.59 cm3 plus raft) took 42 minutes to run off and again according to the software ate 1 meter of filament (from a 333 meter roll that cost me a bit under $50, so with wastage and error less than a quarter's worth of material). Dimensional error was on the order of .2mm; worst on the Z axis.

I gave the XR-311 wheel two shots. It was never designed for this kind of print and lacked sufficient support for the hub or detail scaled appropriately for the .4mm nozzle. Each took in the range of fifteen minutes (the second time I also increased to maximum resolution). Based on that, I could print the whole vehicle in one reservation. A look at the spec sheet from Type A shows it will print at a draft mode (thicker layers) that would be over twice as fast as my first print; I could probably finish a body half of the raygun within that same four hours.

I also note in passing that the bed on the Series 1 is really underbuilt; it is visibly sagging and warped, to the point that no leveling of the machine is ever going to clear it up. Other than that, the machine worked smoothly.

Of course, I took the class on the ShopBot (2.5D wood router) last week as well....

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