Andrew Burks

Tag: Waterjet

Vibratron Auger Testing

by on Feb.25, 2011, under RobOrchestra, Robotics Club, Vibratron

The initial iteration of the auger was just installed into the nearly completed structure.  Mike made some pretty creative parts that will be assembled in the near future.

These clips hold the door brush to the side of the PVC sheel around the auger.  The brush is critical because without the resistance of the bristles, the balls would just roll down the auger.  The clip on the left is different because it needs to clear the motors on the agitation assembly.

DSC00891

These two waterjet parts were, as usual, provided by the generous Richie P.  The one on the left is where the 30 tubes of balls will plug into the agitation/distribution assembly.  The circle on the right is made of steel instead of aluminum.  It acts like a ring gear, and with rubber triangles along the perimeter, is driven to disrupt any balls that might be jammed at the entrance to one of the 30 holes.

DSC00898

This video highlights the first time we turned on the auger after it was mounted in the main structure.  Besides showing the coolness of the auger, it also shows all the progress we made on the structure!

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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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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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Experimental Brake Pedal

by on Aug.08, 2010, under Formula SAE, Pedals

Design

This summer I have had access to the waterjet at NREC where I had my internship.  The current pedal design calls for a series of 2-dimensional parts that I knew I could cut on the waterjet very easily (it can cut through stuff faster than 10 inches/minute, so it’s preferable to a CNC for this application).  Unfortunately I put off cutting these parts until the last week of my internship.  At 10PM on the last Tuesday night of the summer, I realized that I needed to prepare the .dxf files (files that define the shapes of a 2-dimensional part) I would need to cut some parts out after work.

When I went to make the .dxf files, I realized that I could make the entire pedal assembly out of welded steel plates cut from the waterjet.  That night I started making a new version of the pedals (version 9) and had the rough outlines of all of the key parts by the time I went to bed at 3AM.  I also never made the .dxf files I wanted for the next day.

Wednesday night I made the .dxf files I needed for the old pedal design, then spent the rest of the night optimizing the brake pedal assembly for weight.  Here are some renders of the design, as well as some FEA results:

Render - ISO Render - Front Render - Side
Stress Plot
FEA - Stress
Factor of Safety Plot
FEA - FOS

An Exploded View Animation of the Assembly Process

Fabrication

On Thursday night I stayed after work to cut my parts on the waterjet off-hours.  It took about 5 hours to cut three sets of parts for the old design and two sets of the experimental pedal.  Though the brake pedal hasn’t been welded yet, the tabs were easy to press together to get a good sense of what it will look like in real life.  I was really impressed that I could go from concept to completion in only 48 hours, thanks to SolidWorks, NREC, and the waterjet.  Mike was kind enough to take some glamour shots of the final product:

PIC - ISO

PIC - Front PIC - Right
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Initial Vibraphone Designs

by on Jun.18, 2010, under RobOrchestra, Robotics Club, Vibratron

Overview: We are officially crazy

Animusic is a group that makes great computer animations involving “impossible” instruments playing great music.  While considering actuation mechanisms for the RobOrchestra Vibraphone project, somehow we decided it would be a good idea to do something similar to the instrument that takes center stage at 1:07 in Animusic’s “Pipe Dream”:

Details

Right now, 3/8″ diameter stainless steel balls are looking very promising.  Mike Ornstein, Dan Shope and I have subconsciously split up the work into 3 sections.  Dan is working on the mechanism to take the balls and dispense them onto the keys quickly and with a short reload time.  Right now, it appears that this will be accomplished with a group of DC motors.  Mike is working on the mechanism to lift the used balls back up and dispense them to queues leading into Dan’s mechanism.  This is most likely going to be done with an Archimedes screw and a paintball gun style dispenser.  I have been focusing on the structure of the whole mechanism and collecting the dispensed balls and funneling them to Mike’s mechanism.

The biggest problem I am facing with this design is the awkward hole arrangement in the keys.  I basically have two very awkward hole lines I need to support for both the naturals and the sharps.  A string pulled taut needs to go through the holes in the keys and the supports to hold up the key and let it vibrate naturally.  My initial concept involved about $60 of waterjet-cut 1/8″ ABS.  Here is a render of this initial design:

Initial Vibratron Key Support Render

This concept was that with angled plates in front of the keys sloping back toward the keys, as well as slopes over top of those angled toward the center, I could funnel all of the ball bearings into a channel between the two sets of keys.  Unfortunately it takes up a whole sheet of plastic.

Future Concepts

Moving forward, I want to find a way to eliminate all of the unnecessary material in all 32 of those vertical supports.  A bar or two mounted along the path of the key mounts could allow me to build much smaller plastic mounts for each key.  Look forward to another post with more designs, and watch my friend’s blogs for updates on their portions of the project!

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