crash-test-asm

Assembling the prototype

Why would you spend years designing and thousands of dollars building something only to crash it full speed into a solid object? Testing and development. The idea is to do the damage yourself before anyone else gets a chance.

Earlier this month, I traveled to Poland to, well… slam our latest prototype in a simulated crash test and meet the short list of suppliers we have selected to make our pride and joy. What followed was an engineer’s dream and a whole lot of fun.

Building a production equivalent prototype was a completely new level of challenge from the 3D-printed and machined samples of our previous iterations. We used 4 specialist prototypers from 3 continents to make a prototype that is only slightly weaker than what the mass-produced production components will be. Assembly of just one rack took hours where in production we will be able to automate and quality control in minutes.

The finished prototype was so awesome to hold and part of me couldn’t believe what we were about to do. But as an engineer, there is something so visceral and enthralling about ditching the simulations, putting aside the calculations and smashing your work with extraordinary forces.

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First crash test ready to be dropped

Mounting up the test rig with the weighted bike and the prototype fixed together we started the data logger and the camera then let it go. The rearward facing crash was brilliant. The rack stood strong and held the bike firm and safe in its grip. Next was the forward facing crash. This one was not so smooth. Simulations identified the sliding hook as the weakest part of the design so we wanted to confirm how it performed in a real life crash test. We got our answer as the loads crashed down and broke through the main rib in exactly the weak point our computer simulations predicted. While it was one small part of an otherwise successful rack design it was disappointing to see. We analysed the results, scoped out the changes needed and headed home for a sleep after a very long day.

But, back at our hostel there wasn’t much sleep to be had. We pored over data sheets that had been sent off for specifications from overseas and started redesigning the one component that had got in the way of a passed test. We discovered the material strength properties for the prototype hook were less than half what was expected and of the planned production material.  This gave us hope for the current design but regardless we came up with a concept which is far stronger without any negative impact. So, in the end, the break was a good thing and will make for a better final product.

Our trip to Poland wasn’t just about smashing and crashing. We also went to choose a manufacturing partner we could trust to match our obsession with quality. Meeting a toolmaker and watching mass production in action gives you a real feel for a manufacturers level of respect for the environment, the principles of physics, their staff, and themselves.

We were looking for a manufacturing partner that takes pride in cleanliness, quality control and, ultimately, the finished product. During a meet, greet, tour and component design discussion with a supplier, you can see and sense quality (or lack thereof) in every part of the physical environment and conversation.

We had a shortlist based on capability, industry references and personal experience of the team so set out across the country to meet these manufacturers and inspect their facilities. Some manufacturers exceeded our high expectations, others weren’t up to the task.

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Component strength analysis

Injection Moulding is enormously complex. Mastering material selection, injection pressures, mold flow and form is extremely challenging. Experts in the field understand these multiple challenges and solve problems before they even occur. The strength, flexibility and durability properties of engineering polymers are so impressive but they are also immensely confusing without the right levels of knowledge and experience.

Conversations with manufacturers that went along the lines of “Did you consider ‘x’?” or “I have used ‘y’ to achieve ‘z’ with success in the past” were very reassuring and helped us select the right team to produce the Upside Rack. We are now very confident in the team we have selected to manufacture the rack but are keeping an independent team locally to ensure we can manage our own levels of project management and quality control.

So packing up it was off to Frederic Chopin International Airport. I have been away from the family for close to a week and away from riding also. I need to get riding more myself but so excited that we are now imminently close to getting this product in front of a worldwide audience and then getting more people riding more bikes faster.