Bath Zero Emissions’ mission is to build a zero emissions motorbike that will compete in the Zero class of the Isle of Man TT and the MotoE electric motorcycle race series. Engineering students at the University of Bath were tasked with looking into ways to improve the design of the bike as well as the safety of it. In the past, they had used laser cutting, machining, carbon fibre layup and water jet cutting to make parts.
Over time, these proved to have design and development limitations. In addition, these manufacturing techniques took a long time. They could sometimes take days, and sometimes even weeks, to produce a prototype or end-use part. The students wanted to speed this up and improve design freedom.
This led them to 3D printing. After researching the various technologies available, they got in touch with the team at GoPrint3D to find out more about the wide range of 3D printing solutions available. Based on the application, and the parts the team wanted manufacturing, we recommended stereolithography as the best manufacturing method. For this, we recommended the Formlabs Form 2 3D printer.
The team wanted to make lightweight, strong parts that would help the bike get closer to targets of a 100mph average lap speed and 160mph top speed. For this, the weight of the motorbike had to be reduced to offset the high weight of the battery pack. The team decided to start out by 3D printing a battery module casing. They designed the casing in CAD and sent it to print.
It turned out the best material for the casing was Formlabs Grey Pro resin, which is one of their standard resins. The team were able to incorporate push-fit M3 inserts into the model so they could attach other components. They printed a few prototypes before perfecting the design. They also modified the raft so that they could print directly onto the build platform.
The battery casing was 3D printed in stunning accuracy with the part being a perfect physical representation of the digital drawing in CAD. It snapped into place in the bike perfectly. All in all, 95.36ml of resin was used for the part measuring 136.0 x 60.0 x 60.8 mm. It took 8-hours exactly to print, which is far less than the days it takes to machine or laser cut parts. The team saved a lot of money in the process and are extremely impressed with the results.
So impressed they are, in fact, they have since 3D printed a dash mount, fuse casing and emergency stop handlebar mount in Grey Resin. They intend to 3D print more as they progress with the bike build.
You can check out more manufacturing case studies like this one here. Top image credit: Bath Zero.