I recently came across this video showing the manufacturing process of Azub bicycle frames. The process for their tadpole trikes is quite similar so I offer this video demonstrating it to you. Here is their video description:
“At AZUB, we are very proud that an overwhelming majority of production process and assembly of our recumbents take place in the Czech Republic. The rest is done in the neighbouring Slovakia. From the first sketch, continuing with bending of tubes, welding until the last screw screwed up, we produce everything in the heart of Europe!
The production process of all parts of our frames is computerized using the CNC technology, be it for welding of parts for the seat fixation or bending of the frame tube itself. You can appreciate human craftsmanship when looking at the visual aspect of welding on AZUB bikes. Their quality and aesthetics are incomparably better than the ones of frames produced in Taiwan or in mainland China.
The assembly of our recumbents takes place at the AZUB headquarters. It is undertaken by experienced mechanics whove been building up recumbents for almost a decade. Each bike (except the ECO line) is carefully set up according to the height and weight of its future owner and tested prior to shipping. Therefore, when ordering an AZUB bike you can be sure that the bike you’re getting is perfect.”