3.1 – Identity parade
3.2 – Man and machine
Although the welding process might appear straightforward, it’s actually very complex. So to achieve its task, the Weld Shop balances the skill of the factory’s workforce with the precision of its most advanced machines.
In its simplest form, the Weld Shop can be divided into two – the welding stations staffed by skilled people, and those powered by machines. Both stations bring together thousands of individual steel components to create a new bodyshell.
3.3 – Just In Time
Components are built up into sub-assemblies, which are brought together to create a car. Imagine the Weld Shop’s production line as a river, with a main flow being fed by lots of smaller streams. The main flow is known as the Main Body Line, and carries the evolving bodyshell, while smaller streams feed this main line with sub-assemblies.
Within this system it is crucial that parts arrive at the main line at exactly the right time. It’s an early demonstration of Toyota’s philosophy of Just In Time manufacturing.
3.4 – Job number one
Construction of the bodyshell begins in an area known as Underbody Tack. This is where the panels that will become the chassis are first to be welded together.
Each car requires thousands of separate welds, and each of these connections serves a different purpose. Some provide strength and rigidity to the chassis, while others provide anchorage points for hinges or other panels. Because of these variations, each weld is individually designed, using different thicknesses, temperatures and techniques.
Both people and machines are backed by a diligent quality assurance team, whose job it is to regularly inspect the machines and components. Within the Toyota Production System, this is known as Genchi Genbutsu
3.5 – Complex components
The building of more complex body sub-assemblies such as the doors is part of the responsibilites of the weld team. Members of this large team work simultaneously on many different components using a variety of welding techniques. Completed sub-assemblies are fed back into the main body line as the shell heads towards the end of the production line.
Team member Dwayne Hovell, for example, adds braze to the rear doors – skillfully heating up a stick of bronze until it melts, then flows to support the window surround. If the bronze is melted too quickly it won’t stick to the cold metal of the door; it will boil and splash over the pristine metal supplied from the press shop.
3.6 – Check and check again
At every stage in the vehicle’s construction, product checks and inspections are regularly carried out by both machines and humans. Faults are addressed and rectified immediately so that imperfections are not passed on further down the line. This element of the Toyota Production System is known as Jidoka.
Though welding is a highly industrial process, cleanliness and efficiency are hugely important. For example, metal particles introduced in the Weld Shop could have a significant impact further down the production line.
3.7 – Added strength
It takes little more than ten minutes for the side panels to be added to the car’s underbody. However, the bare shell is far from finished; it now needs to have strength added. This ‘respot’ phase takes up to 14 minutes and involves adding extra reinforcing welds to ensure the car is both safe and handles well.
At the end of the Shell Body line the bonnet and boot are attached to the car by hand. The team here also makes a final visual inspection, ensuring that the bodywork is perfectly joined and that the panels are smooth. From here they are lifted on to a conveyor that takes it into the Paint Shop.