Table of Contents

Mark V Chassis


Overview

The current Monitor chassis consists of 8 vertical plates cut from 1/8 in. acrylic, 3 base plates cut from 1/4 in. acrylic, an optics layer also cut from 1/8 in. acrylic, and assorted 3D printed mounting parts (optics mounts, the Galvo/Polygon holder, the cartridge and the parabolic mirror mount). Most pieces are held together with 4-40×5/8“ machine screws and corresponding hex nuts.


Purchase List

Component Quantity
4-40 Square Nut 0.25"x0.25" 40
4-40 Hex Nut 90
4-40 x 5/8" Machine Screw 90
1/8" Black Acrylic Sheets 1x 24×24“ (or 2x 12×24”)
1/4" Black Acrylic Sheets 3x 12×12“

NOTE: Delvie's Plastics is 45 minutes away in 133 West Haven Ave., Salt Lake City, UT, 84115, US. Contact Info: 800-533-5843 / sales@delviesplastics.com A member of the research group could pick them up locally. Otherwise, shipping to Provo is about $12, which costs less to drive there in terms of fuel and hourly rates.

The rest are 3D printed parts.


Vertical Plates

FIXME why the chosen dimensions? (10.125×4.25 and 8.5×4.25) The plates interdigitate with screws going through one plate into the side of the adjacent plates. Overlaps are dimensioned at the thickness of the perpendicular plate.

Power Deck

The Front Plate is intentionally empty to keep the front clean.

Vent Side

The center is left solid to be a convenient place to put the Power Supply. If different supplies are used, the vents could just as easily be moved.

Fan Side

The original design had only one fan port, lined up roughly with the heat sink on the Scanner Shield's power transistor. A second fan was needed to cool the HELA-10 and PHA-101 amplifiers. It's position is arbitrary between the original port and the far edge of the plate. The grille design (besides looking really cool) should supposedly improve airflow while still keeping most fingers out of it (I spaced the bars to make the gap just smaller than my index finger). That can be changed if anyone has an improvement or made an open circle if wire grilles will be used instead.

Back Plate

Comes in 1 and 2 DVI port variants, (just stacks a second port 1 in. down if you need it). The open rectangle is sized for the combined C14 inlet/switch/fuse unit we're using. It's on the side closer to the Power Supply. Opposite, the Scanner Shield holes are positioned to let the Arduino rest on spacers on the base plate with mostly arbitrary left-to-right positioning. The board just has to clear the fan, while also not running into the Power Supply or getting so far from the fan that the airflow on the heat sink is overly diffuse.

Optics Deck

The front and back plates are identical, as are the two sides. Take note that the optics front and lower deck front are NOT identical, but are made to fit together. No holes are present on these besides those for screws to preserve opacity.

Alignment Plate

An oddly-shaped extra piece of 1/8 in. acrylic with some holes for aligning pins and rectangular gaps for the three cartridges. It'll come off the laser cutter in 4 pieces. It's possible the two small sticks spanning the gap between the larger plates are unnecessary, but we're leaving them in place for now. The other two plates can be bolted to the main optics deck plate. Make sure that this is attached on the correct side of the optics deck base so that the optics fan (assuming you're planning on using it) can be above the power supply (otherwise you'll have trouble with wire length coming from the power deck)


Base Plates


Optics Mounts

X-Cube Holder

Pretty simple: it has holes for pins to align it on the optics plate and then the cube just sits in there.

Riser Mirror Mount

This is slightly more complicated. The current design involves two set screws (both at #8-32, one a half inch long, the other ¾ of an inch), and two sets of springs. The vertical springs and longer set screw are for adjusting and holding the vertical position of the upper mirror (the lower is fixed). The shorter screw and springs control the tilt angle of the top mirror. The holes for both set screws need to be tapped after 3D printing. The upper mirror has a pseudo ball-and-socket hinge with the top mount, but it works only debatably well.

Modulator Cartridge

FIXME needs its own page, linked and/or included here.


Galvo/Polygon Mount

Conveniently screws into the top plate of the monitor. Ideally, it should have some lateral travel distance (to control path length), but doesn't at the moment. Its screw holes also need to be tapped for the #4-40 chassis screws. When installing, make sure that the top plate is oriented so that the polygon motor is centered laterally, and the galvanometer is opposite the mounting holes for the parabolic mirror mount (This may require turning it over).


Parabolic Mirror Mount

We actually aren't normally using this right now, mostly for the difficulty of attaching a mirror to it, and the ease of just putting a premade mirror on top of the chassis. It is helpful for portability, though, since it also attaches with chassis screws (how remains to be seen - the holes in the mount could be tapped, or widened and used with a nut).