Thursday, August 13, 2015

Raygun: moving forward

There's been no interest yet in having a second raygun made. But if there was?

The larger part of the labor on this one was doing the CAD, writing the software, and of course experimenting and problem-solving. Since I know how to best prep the material now, and am willing to spend a little extra for such niceties as ordering "polished" instead of the raw WSF, I think painting and assembling a new one could be done over a long weekend.

Once the prints arrived, that is -- and I'd want to make some minor changes to the CAD in any case -- so about two weeks lead time in addition to the assembly time and time for paint to dry.

Done this way, I'd make the following modifications to CAD-for-print; dimension all the holes for sheet metal screws (instead of bolts or threaded inserts), make the pot strap integral, dimension the inside of the nozzle for standard acrylic stock, add locator pins for the side greeblies, and fix a couple errors in the CAD (such as the grip cutout being 1/8" too large on one side).

I'd also make a few aesthetic adjustments; add the same locator/seam hider ridge to the grip as is on the main body, and chamfer the outer edges to better show off the assembly seam.

Of course, I am unhappy with the performance of the electronics. I believe a normal speaker would work better than the surface transducer, and it also should have some sound holes added to the CAD. The LED is a question -- I don't know at this time why it seemed so dim when finally assembled, especially after the great performance I got from an RGB on the desktop. It may be a software issue, a battery issue, an issue with the LEDs I ordered...

Okay; just tested and I learned one thing; the pink acrylic reacts strongly to red (my first test rig) but the "pink" (rather, purple) LED I got on eBay doesn't illuminate it quite as nicely. And the old wattage problem is still there; I was running two 350ma circuits in parallel, but it takes 10x the power to read twice as bright to the human eye. So what I really needed is a 10W red LED, and mod the driver to that.

Which brings up another change I'd want to make to manufacture -- well, really any of them. And that is to make a dedicated fork off the "duckNode" designed specifically for this gun. Cutting and re-routing traces was more fiddly than I'd like to do.

(A second experiment: the "pink" LED does a good job lighting up a well-frosted clear acrylic. Still doesn't answer if it lights up properly on the lower voltage and amperage of the lithium polymer cell).

In any case, these modifications add a day or two of experimentation but basically can be accomplished within the framework of the existing files, CAD and software.

Sure, there are alternatives. I could re-design the print (or merely fill everything in with clay) to take molds, and do resin casting. I'm not set up for foam casting. I would have to mod the prints -- possibly destructively -- to make vacuum former bucks. But either is probably the way to go if I wanted to make dozens of the things. The cost of a dedicated print is somewhat less than the cost of all the molding compound I'd need, and the savings in bulk wouldn't really show up until I hit at least a dozen.

It would probably need a re-design to make the functional trigger, though -- something like a printer or even laser-cut drop-in trigger group.

In any case, there aren't any orders for these things. There are orders for grenades. There is interest in all-metal firearms at the RPF. And there's interest there in the holocron as well.

My next firearm, however, will be a little different. You see, I took the class on the CNC "Shop Bot" router more than two weeks ago, and I really need to run a project through there before what I learned in class completely escapes my memory. (It is already enough of a chore remembering the controls and sequences on vacuum former, laser engraver, 3d printer, and CNC mill when I run in to do quick jobs on those).

The only practical part of this thing will be a spring-loaded trigger. The rest is a test in fast, high-efficiency fabrication; CNC routing of the basic shape, glue, sand and paint.

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