Andrew Burks

Tag: Key Unit

Vibratron Structure Construction Underway

by on Feb.09, 2011, under RobOrchestra, Robotics Club, Vibratron

Metal Cut

After a bit of confusion with OnlineMetals.com, I got all 94 feet of Aluminum 1”x1” in the mail.  I cut it up into the appropriate lengths using the cool new carbide-tipped miter saw in the robotics club.  In the end, there are 54 lengths of angle that all need holes drilled in specific places.  All these pictures are from my cell phone, so bear with me…

40 of the 54 lengths needed for the vibraphone:

Cut Angle

Key Units Painted

The first attempt at painting the key units was a complete failure.  However, Megan Dority suggested that I used primer, and even picked some up for me.  It worked like a charm.  Also, Austin Buchan was able to get the group access to the Newel Simon paint booth, which was a huge help.

Key units drying in the paint booth:

Key Units - Paint Booth

Key units after drying:

Key Units - Cart

Waterjet Parts Donated

RobOrchestra founder and alumnus Rich Pantaleo came through once again for the group.  He was able to obtain a large donated sheet of 6063 Aluminum in just a few days when we needed it most.  Also, he cut out all the parts we needed just a few days after getting the sheet!  I made a few mistakes on those parts, but nothing too critical.  I had to widen half of the slots in the giant half circles because I didn’t account for the thickness of the paint and the oversized hardboard.

Completely assembled and painted key unit:

Key Unit - Single on Circle

Key Unit - Single on Circle (below)

All of the key units on their half circles:

Key Units - On Circle - Top Iso (Prelim)

Key Units - On Circle - Front Close(Prelim)

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Improved Key Unit

by on Dec.11, 2010, under RobOrchestra, Robotics Club, Vibratron

After several attempts at getting the 180 separate parts necessary for the previous vibratron key unit laser-cut, we finally found a feasible method for fabrication.  The father of a roboclub member offered to us the use of his large CNC routing table.  Because Acrylic does not machine well (it is much too brittle) some redesign was done to make the key units out of hardboard.

Design Changes

Hardboard - Key Unit

The biggest change between designs was the decision to not remove the material between key points, exchanging concave cutouts for straight lines.  Each new unit is made of five separate pieces of hardboard, connected by wood glue (instead of plastic welding).  Only two parts per unit are unique, instead of 3, which makes machining prep and assembly easier.

Circular Structure with New Key Units

Hardboard - Full Circle

The new key units attach to a horizontal 1/4” plate, just like the previous version.  The only difference is that instead of two clips and two colder pins, these units attach with just a colder pin.  Nothing else in the structure needed to be modified to accommodate the change.

Machining

All of the pieces for all 30 key units can fit on five sheets of 2’x4’ hardboard.  Hopefully these items will all be machined by the end of the winter break so focus can be shifted to the design and fabrication of the structure instead.  Below is an example of how the pieces fit on a sheet of hardboard.  The labels are engraved .02” into the board, and everything else is a profiling cut.

Cut Sheet 1

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Vibratron Structure

by on Oct.12, 2010, under RobOrchestra, Robotics Club, Vibratron

While I had made some preliminary designs of the Vibratron structure a few months ago, I can now begin to finalize some of the key support structure as the ball dispensing mechanism is finalized. 

Key Unit

Experimentation showed us that the ideal location of the ball dispenser is with the tube perfectly vertical, six inches above the center of a key tilted at 45 degrees.  A modular unit consisting of 4 pieces of lasercut plastic and a gate mechanism was designed to hold the keys and gates in their proper relative positions.

Key Unit - Alone Iso

Key Unit Mounting

A large sheet of 1/4” thick aluminum will be waterjet into a shape that can hold 30 of these key units.  Each unit will be attached to the aluminum by two lasercut clips which are held down by cotter pins.

Circle with single Gate - Front Iso

Circle with single Gate - Back Iso

30 Key Units

With 30 key units on one large piece of aluminum, the weight of the entire assembly is already at 50 pounds with a diameter of over 3 feet.  In the future, the ball recirculation system (an Archimedes screw leading into a paintball hopper) will rise out from the middle of the aluminum circle, and the ball collection system (a foam floor to catch the balls) will stick out below and around the keys.

Circle with Gates - Overall

Circle with Gates - Detail - Front Depth

Circle with Gates - Detail - Back

180 pieces of plastic, over 90 of them unique

There are 6 pieces of lasercut 1/8” red acrylic in each of the 30 key units.  3 of those 6 pieces are unique.  1 of the other 3 pieces has 6 different sizes, and the final 2 are each repeated in all 30 assemblies.

Obviously I did not want to model 98 different pieces of plastic and insert them individually into models.  Fortunately, design tables in SolidWorks are very powerful.  In the end, I only needed to make 5 plastic parts and 5 obnoxious Excel spreadsheets to get an assembly (“Key Unit”) with 30 unique configurations.  Some of the plastic parts even have their note engraved into the side!

Design Table

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