How to make a Mazda MX-5

As a robotic trolley trundles past, carrying a mixed-bag of parts for a Mazda MX-5 roadster, I'm reminded of Christmas. And I'm not really sure why.

After all, it's stinking hot, ear-ringingly-loud as klaxons wail sporadically and heavy machinery thumps and hisses while a large proportion of the 7000 staff employed to manufacture vehicles at Mazda's gargantuan Hiroshima factory in southern Japan artfully go about their business.

It's a hive of activity – albeit not very festive – and car enthusiast or no, it's a thrilling place to be… Even more so with hard hat donned and safety spectacles affixed.

Equal parts chaos and poetry to the untrained eye, a mesmeric collaboration of robots and humans are entwined in a compelling waltz that delivers a vehicle from buckets of bolts, chassis components and plastic inserts in around three hours on the production line.

I ask Mitsuru Uematsu, the staff manager at the huge 2.23 million square-metre Mazda plant if it was a challenge to get the factory upgraded to build the sleek, shark-like MX-5.

His response is short and sharp.

"It's a beautiful and cool car, but difficult to build."

The factory boss explains that there's four (or five, if you include welding) steps in the production line and it all starts with the stamping plant. This is where huge 30 tonne cast-iron 'dies' are used to stamp dull, flat sheets of steel and aluminium into aesthetic splendour.

Watching these huge machines thump down every 10 seconds, developing 5200 tonnes of pressure, is hypnotic. The difficulty, says Uematsu, is creating the exact surface creases and curves that the designers want.

"The stamping shop worked hard to produce beautiful forms and shapes," he explains, pointing out some of the MX-5's more complex body surfaces.

"Nowhere is flat," he insists with a dismissive wave. "The goal is to deliver a car truthful to the original design model."

Once the car's body panels are stamped they are spot and seam welded together and then painted. The paint shop takes up almost a quarter of the entire facility – it's immense! – and like the welding, casting and stamping is fully automated, advanced robots working night and day if required.

The paint 'bots (my term, not theirs) apply four coats of paint to each exterior panel of the MX-5. The paint is atomised or dispersed in such a way as to provide a lustrous coat, says Uematsu, who reckons the colour finish is on par with German cars.

Next the MX-5 'carcasses' move to the assembly area where they are pieced together like a giant, expensive (and sometimes dangerous) Lego set.

Although we weren't allowed to film anywhere inside or outside the factory for obvious reasons, permission was granted to photograph in the assembly area.

Partially-built vehicles glide down the build line on a super-slow-motion rollercoaster of sorts as much of the manual labour is augmented by robotics (to lift heavy parts for instance). But assembly seldom occurs without human hands.

Indeed, the way workers move in and out of the cars, attaching seats or fastening dashboards, installing disc brakes and connecting engines requires the kind of dexterity and feel not yet possible with robotics.

One of the more absurd aspects of the assembly line are the fully automated electric trolleys that lumber around the factory delivering the exact componentry and parts to the line workers when they need it.

There are hundreds of them moving at once and they emit a very familiar acoustic to let others know they're moving.

Thinking out loud, I query whether this manufacturing line could one day be totally automated.

"Unlikely" responds Uematsu, who says the workers also provide a level of quality assurance and craftsmanship that no machine can replicate today.

All of the plant's 7000 workers develop a level of expertise in their chosen area, insists the factory chief, which he says results in high-quality products.

"We want people working with us who hone skills and knowledge. We want the best," Uematsu says.

The objective? "To delight customers".

Eventually the Mazda MX-5s – and CX-3s and Fiat 124 Spiders that are assembled on the same line – reach the final step: inspection.

It's oddly captivating to watch the practised workers run their hands deftly over the cars' various joins, shut lines and panels, as others dash, dart and clamber inside the cars to make sure everything's hunky dory.

Finally the cars are put on a dynamometer to test engine and braking, before advanced safety features like radar cruise control are tested and then the cars go through a long tunnel -- the 'shower' -- to test door seals are water-tight.

Then they are given a short drive around the car park with roughly one in 10 vehicles driven on an extended course for much longer.

From beginning to end it’s a spellbinding process and a marvel of human endeavour. That a car can be manufactured and assembled within three hours is extraordinary – watching it happen is astounding.

As only the second car factory I've had the good fortune to examine closely – the first was the GM Holden Elizabeth plant in South Australia – it's one of those special experiences that I would heartily recommend to all and sundry.

Oh, and I figured out why it felt like Christmas in the factory; the melody the robotic trolleys play when in motion sounds eerily like Dashing Through the Snow. Only in Japan, bless 'em.