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Exploring New Joining Methods: Heat Shrunk Wrap

The Joints Team are exploring several new joining methods. We were inspired by heat shrinking plastic bottles but found that the joints could not withstand the stresses if used on a bicycle. Here we are exploring another heat shrinking method using a PVC wrap typically used in food packing and storage.

Here’s our step by step guide of building a bamboo joint with heat shrink wrap:

  1. Firstly, choose bamboo with required diameters (30mm and 60mm).
  2. Tape around area of bamboo to be cut to avoid splitting. Cut bamboo to desired length.
  3. Make a mitre joint. This was done using a jog to stabilise the drill which was used to cut out a curved end.
  4. Place bamboo into desired angle and position.
  5. Join the bamboo using the heat shrunk wrap. Wrap around a few times and use heat gun at 150°C to shrink material.
  6. Repeat wrapping and heating process around 15 times or until joint is stabilised.

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Whilst this process showed better potential over heat shrinking plastic bottles, there were some significant issues. The joint worked well in tension but not compression. Also, a lot of material was needed to stabilise the joint which results in a very bulky joint adding to the weight. It also lacked aesthetically.

We’ve got other methods in the pipeline. For now, back to the drawing board.

Battery and Motor

This year, Pedal Progress is making an electric bamboo bike. For this we would need two vital components, an electric motor and a battery. For the motor we decided to purchase a readily available rear hub motor due to its simplicity, flexibility and availability in the market. The motor is a 250W 36V hub motor (meeting EU e-bike regulations). As for the battery to power this motor, our goal is to improve the aesthetics of commercial e-bike battery packs which are typically large, heavy and exposed. To do this, we plan to design and make our own battery pack which will be small enough to fit inside of a tube of bamboo (which then is inside our frame!). Below are some photos of the work we have done so far!

Our rear wheel hub motor
Lithium Ion Cells – the core component to any modern battery
Our lithium ion cells connected using Vruzend battery holders. Makes life much simpler and eases prototyping!
Version 1 of our assembled battery pack
Testing rig for the motor and batteries
Our custom-made battery holders! Designed to further reduce the size and weight of our battery pack.
It Fits!

 

Much more work to do till we get it up and running. Stay tuned for more updates!

We proudly announce our new sponsor!

We are proud to receive the Group Project Award from the Institute of Mechanical Engineers (IMechE). We are grateful for the opportunity given to us to showcase our design at the International Cargo Bike Festival on the 11th to 13th of June 2017 (Nijmegen, Netherlands).

The International Cargo Bike Festival (ICBF) is an annual conference for the public, authorities and professionals in the cargo bike industry. The festival will take place from the 11th to 13th of June 2017 in Nijmegen, Netherlands.

(2016-17 Team) Build Phase: Day 1

With continued support and helpful guidance from James (owner of the Bamboo Bike Club workshop) , we decided to build our 2016-17 bike at Bamboo Bike Club.The building phase ran for 5 days. Scroll down and check our lovely photos of Day 1 activities.

Headquarter was set, Instructions were put up. We were ready to build our bike

Bamboo Selection

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Bamboo Preparation

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Front and Rear Jig Set Up

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(2015-16 Team) Quick Fix with JailMake Studios

 

Once the components for the rear axle arrived, our team had another setback of trying to get the components fitted in together. Thankfully we managed to locate a local workshop, JailMake Studios, that offers spot welding services to make our rear axle.

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Welcome to JailMake Studio!
The JailMake workshop
The JailMake workshop
JailMake machines at work on our axle
JailMake machines at work on our axle
The aluminium case for our axle
The aluminium case for our axle
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Jamie just checking whether he has the correct tools
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Our rear axle slowly coming together!
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The finish product!
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Ready to be used and installed onto our frame

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