Assignment 2: Fuel Tank
Introduction
This is the fifth project for BEIL0014 I have been working on, which is to replicate the Harley 883 fuel tank. For this assignment, we formed a team of 9 to create a plywood template of our our 1:1 fuel tank model. The following shows the list of the teammates.
Louis Cheung (me)
Chun Yat Chiu
Alex Sostres-Roberts
Moonjin Kim
Eu Gene Hyun
Yixuan Zhang
Yihui Wang
Wing Yan Chick
Gene Hyun
Procedure
To create this relatively complex shape of metal, a plywood template is created to help us to model the shape.
Step 1: First step will be taking photos carefully around the real fuel tank, 40 photos have been taken in order to create a digital model of the fuel tank, for this part Autodesk Recap program is used. Caution has been taken when taking photos within sufficient light source and evenly showing changes of shape of the tank.
The dimension of fuel tank is also being measured as:
The highest point is 209 mm
Length from top is 396 bottom is 392
Width is 230 max
The following shows the 3d digital fuel tank has been produced in Recap using the dimension measured.
Step 2: After saving the digital file as .rcm type, we then export the file as .obj file into Fusion360 Slicer, which is a tool that turns the 3d model into slices of plywood that can be reassemble again to create a real life 3d model.
The input for Fusion 360 slicer are shown as:
Sheet size: 800x500
Sheet thickness: 6 mm (width of the notches where different part can merge together to form the 3d model)
Model size: (W) 400 mm, only one dimension is needed and the program generated the rest of the dimension.
(H) 209mm & (L) 494.342 mm.
Construction techniques: interlocked slives
Slice distribution: 1st Axis- 15/ 2nd Axis - 15
Step 3: Next, with correct line weight and color, pdf of the templates are created and being imported into illustrator and then print them out in the laser cuter.
We used a relatively low energy for the numbers on the template to avoid them being cut out.
Step 4: To assemble the laser cut template, a soft hammer is used to push the slices together since space between notches are very tight.
Due to human error and changes of lights from different angle,the produced plywood template is not perfectly symmetrical.
Step 5: Wrapping the whole model with cling film
Step 6: For this step, a group of 9 is spitted into groups of 3 and each of the small group produce their own tank. Member of group small group are:
Louis Cheung (me)
Chun Yat Chiu (Iverson)
Alex Sostres-Roberts
We wrap the whole model again with paper and tape and cut accordingly into three parts.
Step 7:We then stick the cut paper into large sheet of aluminium and draw the outline of each part of the fuel tank onto the aluminium.
Originally we planned to create four parts of aluminium but eventually three of us agreed three parts would be easier for this project.
Using the guillotine, we divide the big aluminium sheet into three potion and we then use hand lever shear to cut out individual part precisely.
The three parts that are produced are left side, right side and top side of the fuel tank.
Step 8: Working on side of fuel tank:
We start hammering the product with plastic mallet from the inner side of the metal only since we do not want to dent the surface of the product. Using the sand bag and the mallet, we hammered the centre of the metal to get a general curve on the whole piece. Moving from the centre to the edge of the metal using less force to create a gradual change. English wheel is used to roll even the dents on the edge which slightly folds over to the top pieces of the fuel tank.
Due to asymmetrical property of the template model, we compare the metal to the template very often in within 10 times of hammering.
Next, planishing ball is used to create the bottom end curve of the model which consist of a big curve.
Due to the elastic property of metal, the top edge keep sticking out whenever we tried to get it in place. Eventually I decide to "over-bend "the metal using English wheel and after few attempts it finally fits.
For the edge of the side part, I used a smaller version of English wheel to smoothen the dents created and bend it towards the model to make it fits.
Same for the back of the side parts, we use a smaller English wheel to make the edge attaching to the model.
Step 9: Working on top plate of the fuel tank:
The top plate is relatively harder part compared to the side part due to large size of it.Problem I encounter when working on it mainly is when I hammer the top part perfectly after finishing the bottom part, the bottom part start to deform and change. This means meaning I have to work on the whole part simultaneously.
What I did there to solve this problem is to ask my teammate to hold tight the other part of the top plate when I working on one part. This approach is similar to the tray project I did previously while the face of the plate is being hold by two wood planks with large clamp. Without the clamp, the face of tray would have deform while I was working on the edge. To finish the top plate, English wheel is being used to smoothen all the dents on the edge and smaller English wheel is used to fold the edge of the top plate to the template. We tried many times for this part until we are satisfied.
Due to symmetrical property of the wooden template itself, the finished aluminium product is tilted on one side as well but it is perfectly matching the wooden template.
The finish product are shown:
