One machine looks set to revolutionise the future of auto manufacture, and it really
is a pretty big deal.
Weighing about the same as five space shuttles, it takes 24 flatbed trucks just to deliver
it from the manufacturer, and it doesn’t even fit inside the original Tesla factory.
What’s it for?
How was it inspired by a kid’s toy?
And will every single car manufacturer now be forced to follow suit or fall behind?
Join us as we explore how and why Elon Musk is putting the squeeze on his competitors
and investigate why Tesla installed the 430 tonne Gigapress.
As we may have mentioned before once or twice on this channel, Elon Musk is a man on a mission.
Not content with blasting civilisation off to Mars and helping his adorable monkey mate
play Pong, he’s also ceaselessly hunting for clever ways of making his day job at Tesla
– dragging mankind into the electrical vehicle era – happen faster.
His latest big idea was reportedly inspired by a dinky die-cast Hot Wheels toy car on
his desk.
Wondering, as he is apt to do, what the practical size limit for a die-cast vehicle is, Musk
realised there’s no real reason why full-size autos can’t be manufactured according to
the same design philosophy.
This is, after all, Mr ‘make the machine that makes the machine’.
Finding these sorts of efficiencies is his whole thing.
So in crafting the radical Model Y redesign, which will incorporate Tesla’s new generation
batteries into the chassis of the latest iteration of cars to roll off the production lines,
Musk decided he was no longer happy that the rear underbody comprises a whopping 70 separate
parts.
Each of these 70 parts has to be screwed, welded or otherwise glued to its neighbours
by the way.
That’s a complex and fraught process that consumes a great deal of factory floor space,
energy and time, and allows silly errors to creep in.
Prominent auto industry engineer and consultant Sandy Munro drove the point home when he told
Musk the back of his Model 3 resembled, in his view, a ‘patchwork quilt’.
So in April 2020, Elon Musk announced to the world he’d purchased the two biggest casting
machines in the world from Italian engineering firm IDRA, in order to make giant self-contained
parts – initially the rear underbody of the Model Y.
The mammoth machines – measuring 20 metres long, by six metres high – were installed
at the company’s Fremont, California factory later that summer.
According to Musk, these giant Giga Presses – so big they wouldn’t fit in the factory
and had to be hastily covered up with a rudimentary shelter in the parking lot – will reduce
the number of robots at the factory by 300.
This reduction comes with an obvious simplification for Tesla in terms of quality control, and
production headaches of producing and pipelining 70 separate parts.
That makes the cars cheaper, of course, and thus more accessible for consumers.
Making those 70 pieces fit together like a jigsaw used to require an elaborate and expensive
CNC – that means Computer Numerical Control – process.
That whole CNC step can be skipped altogether now the whole rear underbody is cast in one
piece by the Giga Press.
According to experts, Giga casting will help achieve a 40% reduction in rear-underbody
manufacturing costs.
Not only that, the new single-piece casting design will deliver a 30% reduction in the
size of the factory body shop.
So how does it actually work?
Broadly speaking, all die-casting, from toys to golf clubs to Tesla chassis, work on the
principle of forcing molten metal into a reusable mould.
Once the metal has hardened into the shape of the mould, the mould is opened and the
newly shaped metal is removed.
In Tesla’s case the metal in question is a sophisticated and unique proprietary alloy
comprising roughly 90% aluminium, 8-and-a-half percent silicon, plus traces of copper, manganese,
iron, zinc, titanium and lead among other elements.
A natural gas-fuelled oven heats ingots of the alloy to 850 degrees C, at which point
it has liquified.
Useless slag in the form of aluminium oxide is stripped away, before the alloy is pumped
along heated pipes and circulated to prevent it from setting.
Argon gas and a rotary de-gasser are applied to keep nasty impurities at bay, and the whole
mixture is passed through a silicon carbide filter to remove stubborn lumps larger than
25 micrometers.
To grease up the process before insertion, robots coat the mould’s interior with 35
millilitres of soybean oil.
The mould is then closed, before pumps create a vacuum inside.
The molten metal is then forced into the mould at high speed, to prevent the hot metal from
hardening, with a dash of extra lubricant to prevent it sticking to the sides.
When full, the mould is then opened and cooled to 400 degrees C. The newly shaped metal part
is then moved by robot to a quenching tank, at a chilly 50 degrees C to help it set.
A mechanical trim press cuts off any unhelpful excess, to within meticulously established
tolerances, shunting the waste back to be recycled elsewhere in the process, and the
whole thing is X-rayed to ensure it’s road worthy.
Final trimming is carried out by lasers, then conventional drills go to work getting the
final piece ready for attachment to the car.
Sounds too good to be true?
Critics have pointed out that a big problem replacing 70 parts with one part is that when
the one part is damaged, say by a careless accident, the entire rear underbody is too
awkward and prohibitively expensive to replace.
Elon Musk himself weighed in on twitter to say the car’s “…crash absorption rails
can be cut off & replaced with a bolted part for collision repair.”
If the collision is severe enough the car is of course a write-off.
But that’s also true of most other contemporary vehicle designs.
Another problem, from a manufacturing point of view, is that inevitably during the casting
process microscopic amounts of the mould can get carried off onto the part itself during
each casting.
Eventually the mould itself becomes too big, but they’re obviously replaceable parts
of the Giga Press.
Plus the lubrication stage goes a long way to alleviate this issue.
Certainly Tesla is going all in, suggesting that the current Giga Presses in work or being
installed at Fremont, Berlin, Austin and related machines Shanghai – capable of a clamping
force of 6,000 tonnes – aren’t powerful enough.
To build the long-awaited Cybertruck, Musk is reportedly shopping around for even bigger
machines with a clamping force of 8,000 tonnes.
So will other manufacturers be forced to follow suit?
Industry analysis by JPMorgan suggests the big companies will struggle to reinvent their
own production lines as radically as Tesla can.
But smaller EV startups and agile cashed-up Chinese firms will be looking closely and,
in JPMorgan’s view, should be investing in their own Giga Presses before long.
Any self-respecting 21st century company will surely jump at the chance to reduce its factory
floor footprint, number of robots, and needless labour hours spent jigsawing vehicles together.
So whichever way you look at it, these house-sized machines look set to make a big impression.
What do you think?
Will cars inevitably consist of fewer and fewer parts as the casting system improves?
Let us know in the comments, and don’t forget to subscribe for your next molten-hot injection
of tech content.