Assignment 2 Project: The 1:1 Scale Fuel Tank

Step 1:

As a team consisting of 10 multidisciplinary members, we will create a 1:1 scale plywood template first, replicating an existing motorcycle fuel tank and then divide it into thirds. As individuals we will apply our skills learned from the previous assignment and create an aluminium skin to adhere to our third of its contours.

In our first group meeting, we decided to choose the fuel tank by Andrew Wallace for this assignment and downloaded its digital model on Moodle. We exchanged everyone’s abilities and ideas of how to create the perfect template of the fuel tank that can help us approach this assignment in the best way. So we all agreed we create the strong and rigid template of the fuel tank together, and using the template’s surface to create the aluminium skin by using the hammer forming skills from the previous assignment.

We prepared the 3d model of the fuel tank by Andrew Wallace in 3DS MAX and import it into Autodesk Slicer for Fusion 360 to prepare our fuel tank template for laser cutting. As we all discussed before, we have learned from previous assignment that we need more rigid and harder surface of template to hammer the metal more efficiently.

We planned to build the model using total 26 slices on both axis, which means 13 slices on horizontal X and 13 slices on vertical Y. Total 26 slices used a total of 9 sheets of 3mm plywood, which was an acceptable number.

As we did not want the slices being too difficult to slot together, we chose to ensure that the slot width is slightly wider than 3mm. Also, we needs the extra space for inconsistent material thickness for putting glue between. So we all agreed the slot width is set to 3.5mm.

After laser cutting all the slices we need for the template, we needed to assemble them to our final model template. So, all the Y sections were placed into the Z sections.

We used the glue to help us assemble model. We removed the slices of Y sections one by one and filled the glue into the slot, then place them back into the position in the model. This glue technique can make the model rigid and strong.

Step 2:

We as a 10 members’ group decided to form into two smaller 5 members’ team that will each team make single aluminium fuel tank. In our group, our 5 members are: Feimo Song, Yikai Chang, Jichao Guo, Gengchen Yang and Tianshuo Liu.

After small team meeting, the fuel tank skin will be divided into 3 elements, 2 symmetrical side parts and 1 top part, Me and Jichao Guo will make the top part of the fuel tank skin together.

First, we should use the tape to divide 3 parts on the template, and using paper to indicate all the areas which needed to be shrunk and stretched for my top part, as it crinkled in the areas which the aluminium was to be shrunk. I used pencil to mark the shape on the paper and cut the paper template using scissors on the pencil marking line.

The paper template was taped onto the aluminium sheet and using pencil to draw the mark of shape on the aluminium. A variety of different tools were used to cut and trim the aluminium sheet including guillotine, tin snips and a file to finish the edges. When cutting the aluminium, I left the extra space on the margin of pencil mark, which will prevent the sheet shrink into smaller size after hammering it.

I used 3 wood battens and 2 clamps to make a simple bending tool on the table. Basically, my aluminium sheet underneath the middle batten and bend the aluminium on the edge of the table to make a good curve as my fuel tank template. The advantage of this bending tool is that it won’t get the clear bending mark on the aluminium, also I don’t need much effort to bend it.

The bending tool will give me a good curve of the aluminium on the longitude axis, but my top part of the fuel tank also has a little bit curve on the latitude axis, as the both sides of the sheet need to cover other two skins of the fuel tank.

Step 3:

It is a long progress for making the top part, I used different sized hammers to strike the aluminium, and at the same time, I constantly went to use the English Wheel to make the curve smoother.

After a long progress, when I got comfortable with the shape, I quickly switched to using a sandbag to smoothen the lumps and dents made from hammering. The English wheel really helped improve the appearance of the part, as the bumps and dents were easily restored to normal.

In this progress, I found it is difficult to balance both curves on horizontal and vertical axis, which means if I strike a perfect horizontal curve, the aluminium will become flat vertically and vise versa. Also, I found it is difficult to make a good symmetrical aluminium for my top part, because the sheet is too big to control the curve of the sheet, when striking it will slightly tilt to one side and hard to adjust the shape. Therefore, I found it is very challenged to make this top part during the progress and I need much more patient compared the previous assignment.

Also, there is a gap on the back of the fuel tank, I decided to cut this gap off at the end of the making process. So, I use the same method as previous that cut a paper template first from the fuel tank model and tape the paper on the right position of the aluminium, then using the pencil to draw the marking line and using tin snips to cut the shape off. I still needs the file to finish the curve edge of the gap.

Step 4:

After my top part was completed, as a good team member, I went to help other members for their side part. I helped them hold the aluminium and tight the sheet on the surface of the template, then they can strike the hammer on the aluminium to create the same curve of the template.

Also, we used the bead roller for the both side parts of the fuel tank, tipping the contour line of the top part on the side parts to make the top part edge perfectly covered on the tipping line.