Monday, August 3, 2015

Raygun XIV.I

TechShop is sort of bugging me. One lathe is still busted. Still only one printer, and not only is that reserved most of the time, it keeps getting dragged off to be used in some sort of afterschool outreach they are running. And today...the bandsaw was busted (and like the lathe, the parts may take weeks to arrive, if ever... apparently Jet Tools is not the best at support).

With no bandsaw, I made do with file, hacksaw...and mill. Was actually able to use the mill to cut the pieces I wanted to width and length, then used grinder and file to do the final shaping.

My CNC parts went okay. I seem to have forgotten which corner needs to be set to properly zero the various steps; my G-code had the cuts way off in space. So I eyeball zeroed the CNC mill to where the cuts would land on my stock -- lots of air passes to make sure I was getting it right.

After I broke my old end mill that other day, I've been a lot more conservative in my G-code. So much so I was able to dial up to 100% machine speed over-ride (aka, running the G-code as written) and the mill sounded just fine. 8 ips, by the by, step-over of 30%, and a plunge depth of .04" on a .25" end mill.

V-Carve Pro is not the most complicated software out there, and I didn't want to play with trying to face my stock. So I faced on the manual mill, and exported only the contour cut-off path from V-Carve. That worked fine...but facing with a 1/4" end mill takes a while! If I had really gone through with making the raygun all metal, I would have had to break down and purchase a face mill ( can get one for under a hundred bucks on eBay).

Clean-up was the other reason I chickened out on all-metal. There were several notches in the parts I ran off today that the end mill couldn't reach, and I spent a good hour with a file working on that. And these were simple outlines; the main parts with all their compound curves are giving me a hard time just with sandpaper and the soft plastic I got back from Shapeways!

(And, yes, there are several errors in the CAD. I've been having to cut into the plastic in various places, as well as add more material with scrap plastic and superglue. The revised e-cell connector took even more than that; I assembled that with Apoxie Sculpt.)

Well, the metal parts fit. The sound board is a lot smaller than I thought, but jammed up against the housing and fed a strong audio signal from my computer, it seems sufficiently loud anyhow. But that means that, more and more, assembly is bleeding into electronics assembly/final assembly. And that means I have to finish most of the painting.

And painting is currently waiting for the trial piece in epoxy enamel to finish curing so I can evaluate if all the pieces are going to get that treatment. At this point, it looks like the combination of superglue seal on the plastic and epoxy enamel as final coat will give the tough shell I need, and Rub 'n Buff will give a metallic sheen that will look appropriate and last a while.

And oops. Before I put on the final coats of paint I really need to print off the "swooshes" for the side. If and when that last ailing 3d printer at TechShop even becomes available again!

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