|
Meg Chen |
University of British Columbia |
PHYS 420C (2024) |
Materials
(all the measurements are in millimeters)
(Please
refer to this Onshape Design Link for more detailed dimensions)
|
I made my cart with only two sides and without the
funnel, but I have included the designs in my Onshape Design Link, so feel
free to include them for your cart. A lot of the materials used for the cart are 3D
printed, so for more detailed dimensions, please refer to the Onshape Design
Link above. |
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Two
balls, one significantly heavier than the other -> Objects to be launched
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Make sure that
the balls are around the same size and that they are both smaller than 40mm in
diameter (or it will not fit in the cannon)
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Heavy
object that cannot be easily broken ->
to act as weight accelerating the cart
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I used a scrap
piece and added brass material objects to it
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Thread/thin
rope/yarn -> to hang the heavy object
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Cart
body
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Base
(6mm polycarbonate material, cut with waterjet cutting machine)
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Sides
(6mm polycarbonate material, cut with waterjet cutting machine)
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This is the
long side. Please prepare 2 pieces of this.
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The design for
the other two sides is included in the Onshape Design, please refer to the link
if you want them.
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Cannon
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I prepared
this piece by first cutting the desired length from a wooden tube with a
handsaw, then I used a milling machine to drill the slots.
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When preparing
this material, please choose a tube made from smooth material to minimize
friction.
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Flange
(3D printed) -> to hold
the cannon in place
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Piston
(3D printed) -> to keep
the ball in place and push the ball up
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The indent in
the middle was designed so that the ball doesn't roll around in the cannon
while the cart is moving.
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Two
rods (4mm diameter, 150mm long, aluminum) ->
to hold the wheels
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Rod
(4mm diameter, 60mm long, aluminum)->
to hold the piston
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Rod
(3mm diameter, 60mm long, copper) ->
to lock and trigger the launch
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Metal
sheet (1 x 5 x 7) -> to lock
the trigger in place
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Dimensions do
not have to be exact as long as the metal sheet is 1mm
thick.
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Wheel
(3D printed)
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Please prepare
4 copies of it.
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Spacer
(3D printed) -> to keep
the wheel from sliding around
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Please prepare
4 copies of it.
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Spring -> to push the ball up
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I took mine
from a spring-loaded pen launcher, and the spring is around 90mm long
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You would have
to experiment with different springs to find one that has the right amount of
strength
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Spring
holder (3D printed) -> to keep
the spring in place
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Hook
(metal) -> to attach to the train
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I made this
piece with a scrap piece of metal sheet I found by cutting and bending it into
the shape
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Two
rubber tubes (around 10mm long) ->
to keep the piston in place
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I got mine by
cutting two small pieces from the material below, but anything should work
(rubber band, hot glue, etc), as
long as it does the job.
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(image
retrieved from fisher scientific)
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Sandpaper
-> to smooth the edges of the materials cut
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Pipe
Clamps -> to restrict the movement of the piston where
needed
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8-32
lock nut x 15 -> to
attach the flange and the cannon
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8-32 x
1/2" bolt x 15 -> to
attach the flange and the cannon
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#8 x
3/4" round head wood screw x 12 ->
to keep the cart body in place
TIPS:
1) It is
important to make sure that the strip on the cannon cut with the milling
machine is straight, and that the edges of the cannon are horizontal (not
slanted), or the demonstration will not work.
2) Make sure that
the material of the piston and the cannon does not create a lot of friction.
3) For the metal
sheet, note that the material will wear off overtime, so choose strong material
or have replacements ready.
4) You can
redesign the spring holder so that it fits your spring better.
5) After
preparing the hook and the cart body, remember to sand the edges for safety
concerns.