Template:
With
the final design of the tank completed we were ready to laser cut and assemble
the template. Within grasshopper we used a previously made script by our team
members to waffle and orient the pieces within rhino. These waffled pieces
could then be baked into vector lines and exported to Adobe Illustrator.
Illustrator is used to set up the laser cutter sheets by setting vector line
thickness’ and vectors colours, these two variables are important as they match
the laser’s thickness and red is the colour used to know when to ‘cut’,
compared to blue for example which tells the laser cutter to engrave. Finally,
the sheets were exported to the Trotec laser cutting program ready to be cut.
The settings needed within illustrator and the Trotec (laser cutting program)
are listed below:
Illustrator:
- Vector line thickness: 0.001 mm
- Vector line colour: RGB Red 255
Trotec:
- Material: Birch Ply
- Material thickness: 3 mm
With
all the pieces cut out, it was then just a matter of putting the pieces
together, this can be done two ways, by either referencing the pieces with your
3D model and doing it by eye or by putting them together in order by the
engraved labels that reference the orientation and order of build. We used a
combination for both.
Panel division + Forming techniques:
The
first step was to divide the tank into three sections amongst us. It was
obvious that there would be one top panel which would be done by Branko and two
side panels were done by Daniel and I. The reason it was obvious is that
dividing them by these sections they would require the least amount of severe
changes curvatures. Using
the knowledge gained from assignment one we then began to apply that to figure
out our metal forming process.
Top
Panel - The top panel was inspired by a torus with reverse curve
Side
Panels - The two side panels were inspired by the blister
Blister:
After
ex tenuous thought of applying teardrop indentations on the side panels, were
came across with the idea of using a blister to provide a shape to fit well on
the template. From Assignment 1 we figured that blister was not too time
consuming and easy to smooth out with the right type of tools and equipment.
Below
is the process of creating the blister template from 50 mm plywood. We used a
jigsaw to produce a correctly proportions outline of that blister indentation
we desired that would follow the contours of the waffle template. After the
outline was produced on two pieces of plywood we used the bobbin sander to
create a smoother outline for the desired shape.
Next
we utilized a handheld router to create a smoother edge. This was because we
wanted an smooth edge of the blister that lead to the flat sheet metal around
it. Then we put together the template using bolts as a tightening system.
We
started to create a smooth flowing blister using a wide radius nylon mallet,
whilst also hitting gentry for gradual stretching of the sheet in the blister
template. Later we moved towards using custom wooden tools that were used for
particular jobs such as smoothing edge curves of the blister as well as reaching
to tight area of the blister template where nylon mallets couldn't.
There
were many moments of deconstructing the template to see what curvature was
produced as we as following the templates side contours.
With the blister reaching a desired indentation for the side panel we touched up any
inconsistencies in the curvature of the blister and smoothed out high and low
spots with dollys and utilizing the small English wheel.
Once
trimming the side panel from the blister aluminium sheet from the paper
template we compared and touched up the curvature of the front part of the side
piece using the English wheel and a stump.
Final
step of providing the reverse curve on the blister was to smooth the edges out
of the blister to make the edge let stiff and more malleable for a reverse
curve. We discovery that the reverse curve of the side sheets where difficult
to create utilizing various methods of curving the aluminum. Manually forming
the curve was too difficult was it produced various dents due to the stiffness
of the blister.
Blister outcomes:
We
tried forming the reverse curve using the English wheel and dollies. This did
not play out as the English wheel formed out the degree of the indentation we
desire to suit and also the with the dollies the sheet needed to be anchored
but this produced huge dents and buckles in the surface. At this moment we
needed to re-evaluate an easier method of producing the side indentations with a
reverse curve.
Top surface: Branko
The upper surface consisted of a number
of complex curvatures. Individually, they are easily replicated. Although, when
applied to one sheet of aluminium, they act upon each
other to make any subsequent changes difficult, globally affecting all other
elements in the sheet.
The sheet of aluminium had to follow
the sloping contour of the tank, while also maintaining a ‘V’ like taper from
its centre, to its edges. This was particularly difficult when considering that
it is a very slight taper that was easily disrupted by shaping elsewhere.
Furthermore, the receding width from the top of the tank (aluminium sheet) to
the bottom along its contour added another element of complexity to the V taper. It then
slightly folded over to join to the remaining panels.
The sheet was first shaped using a
stump with a curved centred cut out, this allowed for the centre line of the
sheet to be shaped deeper than its edges; forming the crude shape of the V,
seen below. During this process the sheet was also being shaped along the
circumference of the stump in order to follow the profile of the tank. This was
done excessively so that any flattening at later stages was accommodated for.
Following this, the impacts were
smoothened using the English wheel, taking special care not to flatten the
centre line of the sheet, keeping the deepest point of the V taper. Also using
the English wheel perpendicular to the sheets centerline in order to help the
profile curve while maintaining smoothness.
The difficulty being that every time
the impacts were smoothed, it flattened the top of the tank away from the
tapering profile. The curvature that followed the side profile of the tank
needed to be exaggerated, so that when it was smoothed and flattened, it would
return to resemble the profile curve of the tank (profile outline in blue
below).
Given that the centerline indentation
does not continue to the edge of the sheet where it would meet the
handlebars/frame, it flowed into a circular concave. This portion of the sheet
was shaped using a spherical metal dolly, the center line faded into the concave
which subsequently neighboured the front edge of the sheet. The curvature on
the front edge and sides made this are of the sheet quite stiff and hard to
shape, outlined in blue below.
While shaping using the dolly, impacts
needed to be relatively light in order to avoid an overpowering spherical shape
in this area. Moving the sphere along the edge, while avoiding the centre line
helped achieve this shape.
The use of the stump and English wheel
served to predominantly curve the metal while this surface needed a flatter
transition from centreline to edge. In consideration of the profile curvature, a
custom wooden tool was used to help flatten the undulation from centre to edge
on either side, seen below. A tool is used because the English wheel flattens
the sheet excessively, this way impacts using a tool with a flat contact
surface proved more useful. A sandbag underneath the metal helps displace some
of the force and better shape the sheet.
When using the custom
tool, it is important to symmetrically impact the metal, replicating the
process on both sides, this avoided the loss of symmetry. Beginning at the
widest point of the sheet, working down to the thinnest. Again, it is important
to avoid the centre line, as it is the origin point of the V taper, flattening
it would be counterproductive.
The sheet slowly formed into its shape,
checking with the original mold, it fit well, although in order to gain a
better joining edge the sheet edges needed to fold over to meet the side
panels. Using a combination of the dolly’s below, the edges were gradually
folded over. Similarly, beginning from the widest point.
During this stage, it was important to
keep referencing the original mold, as well as the side panels. This way the
edges would meet with greater accuracy to the remaining pieces of the tank.
The tapered dolly was used at the wider
parts of the sheet although not excessively as it would also flatten the
overall profile curvature. The curved dolly was predominantly used, while the
tapered dolly accommodated it in areas that had less acute edge folds. It also
became apparent that the excess material we allowed ourselves during the
template stage came in use. The extra material helped ease the process of
folding. Although in some areas it was obtrusive. In this case, the metal was
cut away slightly using snips or a sheet cutter. This sometimes deformed the
pre-existing shape at the cutting location but it was not aggressive enough to
deform the sheet globally. Gradually through the process of shaping, a cyclic
process emerged where overworking the material would cause it to flatten.
This caused a return to the stump hammering and subsequent smoothening,
followed by the more intricate edge folding and concave processes. The most
effective way to achieve the end was restraining from any excess all of these
shaping processes. An excess in any one tool/process would negatively affect
the rest of the sheet. It was important for each process to mediate the next,
predicting the reaction of the metal to a given tool or action. This mediating
did extend the shaping process significantly, but it was necessary in order to
maintain symmetry and achieve the final form, viewable below. This form was
then polished and mounted along with the side panels on the mold.
The
top piece of the tank is a deceivingly simple component in appearance, however
during construction it revealed many complexities in its formation. The centre
line of this piece is the origin of chamfer to its surrounding edges. This
meant that the centre line was the lowest point of the tank, as opposed to the
highest in most traditional tank designs. This design feature served to impede
motion globally in the sheet, making it increasingly difficult to make
alterations elsewhere on the sheet without affecting the central chamfer.
Furthermore, the profile contour of the tank added another element of
complexity to the shaping of the final form. Previous knowledge gained from the
‘Torus’ assignment helped significantly in this area, although many
difficulties were experienced where the sheet flattened upon any smoothing
attempts. This required a highly localised approach with custom wooden tools in
order to remove irregularities in curvature and symmetry. It seemed as if the
sheet was in constant tension globally because of the central feature. In
reflection, it may prove effective to initially fold the sheet along the
centreline to a certain degree, and approach work as a division of right and
left side (of the centreline). The experiences gained from this
process are invaluable in understanding the material properties and behaviour of
metal and fabrication.
Side Panels: Ryan & Daniel
After
finding out the blister was not the best method we had to re-cut new side
panels and decided to approach it with the same technique as the top panel, by
using a torus with a reverse curve. The idea behind using this technique is
that it will allow us to make the side panels malleable to achieve a reverse
curve with an indentation on each side that is symmetrical. First method
included with having an extra 20 mm around the whole side panels for achieving
some tolerance when joining the 3 pieces. This extra material would allow for
tolerance with shrinking and stretching the side pieces in particular areas.
After
we started to look back at the processes that worked successful doing
Assignment 1 “the Torus”. This incorporate the methods using a round wooden
stump with a recess on the side. This recess provokes the sweep whilst on the
flatter parts produces a reversing curve. This method needs to be carried out
with care as bucking and denting prevails across the inner sweep.
The
utility of various sizes of nylon and wooden mallets started of that producing
the inner sweep gradually starting from a very wide mallet to a very narrow
mallet that could stretch the inner sweep to the desired degree. Various
changes where made in the sizes of the wooden stumps this is because the waffle
template changes direction and size of the inner sweep. So a larger and a low degree sweep stump was be suitable to start from the start of where the
indentation starts on the side panel. A smaller stump was needed for a tighter
and high degree sweep.
This
method incorporated two variables of curling the overall side panels in one
direction with also producing an
indentation that gradually came into the front end of the piece and ended as a
exaggerated effect towards the end. We figured that doing this method slowly
with care produced grater results than just forcing the piece to adjust to the
stumps overall shape. This ended up saving critical time in producing the form
of the side panels and produced easier finishing methods that were to come.
Once
we got the desired fitment, degree and curvature of side panels against the
waffle template we utilised the smaller English wheels to smoothen out any high
or low spots. We utilized the smaller English wheel due the degree of curvature
of the side panel wouldn’t sustain shape on the larger English wheel due to the
width and degree of the wheels.
The
small English wheel also was utilised to exaggerate a bird wingspan shape or
sweep. By applying horizontal pressure to the side panels whilst in the English
wheel made the overall shape further exaggerated. This benefit was more time
efficient and had more even finishing than using a dolly whilst also smoothing
out any minor high or low spots across the panel.
Once
we were pleased with the degree, smoothness and curvature of the side panels
that followed the waffle template, we decided to concentrate on the front end
of the side panels and figure out practical methods of producing a evenly
curved from piece. With the pleased experience from Assignment 1 “the Bowl” we
decided to use a similar method of using the English wheel but producing a
change of degree or “flick” with every finishing roll on the larger English
wheel. This produce the degree of curvature we wanted whilst keeping the form
of the indentation across the piece. This was a risky method due to a high
possibility of denting the start of the reverse curve and sweep of the
indentation. But in the end, it payed off due to the care taken and applying
intervals of light force to the sheet.
After
this process we had to start looking into the joining process of the top piece
in relation the side panels. With reference to all panels we decided to
exaggerate the outer curves of the reverse curve, so it could meet underlap the
top piece with the same angle and have similar degree in meeting areas. This was
done using various types and shapes of dollies. This relied heavily on symmetry
and alignment of the panels.
Joining ideas:
Throughout
the process of making the panels we kept into consideration that we would
potentially have to join the pieces together. We did this by leaving 2 cm of
extra material along the edge of all the panels when we initially cut it, this
would allow us to use this extra material to fold over each other which could
then be able to be welded together or simply pop riveted.
However,
we soon found out it was not required to join the panels together for
submission so we then decided to use this extra material to carefully trim and
fold a neat overlap between the joining sections.
Group reflection:
We
are surprised and pleased with the result as we have had no previous experience
in metal forming and shaping before starting BEIL0014. There was good communication
within the group where all pulled their weight and tackled their
responsibilities well. Our final opinion on the shape we customised is we that
we are pleased with the scale and details of the bike. We also have minor
adjustments or recommendations individually about the degree of the form and
shape. The experience has provoked great skills that will be utilised in the
future. We can see our custom designed 1:1 fuel tank portraying a range of
characteristics from earlier assignments such as the torus, blister, tray and
bowl. From these characteristics we can see how each methods and form can have
implications and applications in industry in relation to shape, form and
strength of metal working.
Personal reflection:
The top piece of the tank is a deceivingly simple component in
appearance, however during construction it revealed many complexities in its
formation. The centre line of this piece is the origin of chamfer to its
surrounding edges. This meant that the centre line was the lowest point of the
tank, as opposed to the highest in most traditional tank designs. This design
feature served to impede motion globally in the sheet, making it increasingly
difficult to make alterations elsewhere on the sheet without affecting the
central chamfer. Furthermore, the profile contour of the tank added another
element of complexity to the shaping of the final form. Previous knowledge
gained from the ‘Torus’ assignment helped significantly in this area, although
many difficulties were experienced where the sheet flattened upon any smoothing
attempts. This required a highly localised approach with custom wooden tools in
order to remove irregularities in curvature and symmetry. It seemed as if the sheet
was in constant tension globally because of the central feature. In reflection,
it may prove effective to initially fold the sheet along the centreline to a
certain degree, and approach work as a division of right and left side (of the
centreline). The experiences gained from this process is invaluable in
understand the material properties and behaviour of metal.
Final images: