1. FUEL TANK PLANNING STAGE

WEEK 7

18/4/18 TUTORIAL

This next assignment requires a multidisciplinary team and the first goal is to create a 1:1 scale plywood template, replicating an existing motorcycle fuel tank. Afterwards, we must apply all our skills learned from the previous assignment to create an aluminium skin that adheres to 70% of the fuel tank body.

Our group name is kloud9, consisting of nine multidisciplinary members:

Natalie DOU - Interior Architecture

Jeremy HIZKIA - Industrial Design

Kelvin IP - Architecture

Ben LE - Industrial Design

Lornia SHI - Industrial Design

Me (Yu Jin Son) - Industrial Design

Zoey SONG - Architecture

Tauqir ULLAH - Industrial Design

Zeran WANG - Industrial Design

We decided to work on the custom fuel tank for the CB550 done by Andrew Wallace.

24.4.18 GROUP MEETING:

We held another meeting as a group to exchange everyone's availability and ideas to tackle the Custom Fuel Tank by Andrew Wallace for this assignment. We thought the best way to approach this assignment was creating a strong and rigid template of the fuel tank, at a 1:1 scale, and then using the template's surface to create an aluminium skin that adheres 70% of the fuel tank using the hammer forming skills obtained from the previous assignment.

RESEARCH
Russell suggested last week that we should import our 3D models onto Autodesk Slicer for Fusion 360 to prepare our fuel tank template for laser cutting or CNC machining.

However, before moving onto any direction, we as a group decided to form into smaller teams that will each research on other approaches to make the Fuel Tank template. We have learned from assignment 1 that a more efficient way of hammer forming metal required a harder surface, and we weren't all convinced that a skeleton model made of plywood was the only option. 

Laser Cutting - creating a full scaled skeleton model of the Fuel Tank:

The major benefits for using laser cutters are the time efficiency in converting the 3D model of our fuel tank onto Fusion 360, using Autodesk Slicer, as well as the low cost benefits in preparing the Fusion 360 file into the fuel tank templates for laser cutting.

The cost of the material was also an important factor when laser cutting. We thought it was crucial to choose a thick material that also quick to cut, so we think a 6mm thick basswood would be a good option.

Cut sample

Assembling the cut templates should be quick and effortless, as the fit precision of each parts have already been finalized through the Slicer program for Fusion 360. Assembling the parts should, at the end, reveal a 1:1 scale skeleton model of fuel tank, identical to the 3D model provided by Russell.

After discussion, we agreed that the challenge here was creating an aluminium skin over the Fuel Tank's body.

The reason why we initially thought the material thickness was important was that we would eventually use the surface of the 1:1 scale skeleton model as a bed to hammer form our aluminium sheet, which would create an accurately formed metal skin for 70% of it's body.

We thought this was also risky, as we worried that hitting the surface would cause chips and eventually break down the skeleton model, and so we also considered covering the model using a wide-spread masking tape, hoping that it would soften the blows between the metal and plywood surface when hammering.

30.4.18 - PATTERN MAKING

We later learned that mask-taping the skeleton model can enable us to identify the contours of the fuel tank body, locating where the curves occur and labeling the depths. 

Knowing this, we then can trace these curves onto paper and transfer the information onto the aluminium plate to hammer form without having to use the skeleton model as the surface.

This step avoids damaging the model as the papers are used as guides to form the aluminium skin, while at the same time would cost a time of trial and errors to ensure that the skin can precisely fit onto the model.

CNC Cutting - creating a solid model of the Fuel Tank:

Using the Roland CNC cutter inside the FabLab, CNC Cutting generally comprises of two steps: 'rough cutting', which involves cutting/shaping a material block into the model with a rough, contoured surface, and then 'finish cutting', which cuts away the rough surface into a finer finish. Both steps require two different drill bits.

Unlike the laser cutter, the CNC machine eliminates the need to import the Rhino/Grasshopper Fuel Tank file onto Fusion 360, using Autodesk Slicer, and instead be imported into a Step File for the CNC prepping program.

We spoke about it with Martin and agreed that the CNC machine wouldn't be able to cut the entire fuel tank through one job due to the following reasons:

1. Fuel Tank model is too big to cut.
2. It contains undercuts, something the Roland CNC cannot do since it operates only on 3 axis' (x,y,z).
3. Based on past experience, a lot of errors, both human and machine, can occur when doing a cut job in one go which ruins the entire model, e.g. the drill bit might break off due to the excessive friction caused when in contact with MDF.

An alternative Martin suggested was for us to divide the tank (on Rhino or Solidworks) into panels and then print each of them out with the CNC on MDF. Once we've printed them all out, we then glue the panels together, achieving a full scaled model of our fuel tank.

We considered this modelling template as an alternative to the skeleton model method done by the laser cutter, as it is a simpler way to hammer form the aluminium sheets on top it afterwards, due to it's versatility, rigidness and detailed surface. 

This was inspired by the previous Tray exercise where we hammer formed our trays using a timber template as the bed.

Alternatively again, we can divide the fuel tank model into three separate bits and then cut out females moulds using the CNC, and simply hammer form the aluminium skin inside.

A major benefit in using the CNC machine is that the final model would eliminate free metal forming, since the model is strong enough to be used as a template to hammer form over. In contrast to this, the model may take a great deal of time to make and the cost of using the Roland CNC machine is relatively high.

Hand Making Template (Gonz Method) - Making the Fuel Tank model by hand:

Lastly, we've considered making our Fuel Tank model using a technique I've learnt from a past tutor in my Industrial Design studies a few years back. I don't know the technical name for it, so I'll call it the 'Gonz Method' because the tutor's name was Gonz.

This method involves cutting out evenly leveled contours (made of timber) at certain heights in accordance to the fuel tank. Afterwards, we then glue the timber contours together, and lastly, sand down the contoured edges down into a smooth surface until the model is identical to that of the Wallace Fuel Tank.

Example of someone else's work displayed outside the Design Lab...pretty sure they used the same method. In this case, the model the contours have gaps in between.

This technique is a common practice in product design as it is mostly done by hands, with the finishing result being aesthetically pleasing to look at. However, it also requires time, patience and effort to complete, which may affect our metal skinning process that comes afterwards.

CONTINUE ON TO PART 2...