- [Instructor] The comprehensive history
of making things via molding is almost as long
as the history of the people who were making them.
For now I'll zoom in on some key technological advances
relevant to this course in particular.
Some of the oldest evidence of moldmaking
and casting is found from the Mesopotamian civilization
wherein bronze bowls were made using sand casting.
As the technology developed artisans would
hand carve wax into the master shape and cast it.
These ancient examples were often small pieces of jewelry
or religious artifacts.
Other methods of moldmaking and casting
made use of biological resins
like animal horns and tree gums to make master forms from.
Due to limitations in materials and available technology
these were usually small scale goods
made by master craftsmen custom to order.
Prior to the industrial revolution
the craftsmanship era was defined by cottage industry,
i.e., artisanal goods made at home.
Made objects, especially the ones
using moldmaking techniques, were made to order,
unique, and difficult to produce.
A considerable amount of skilled labor and craftsmanship
was required for the construction of everyday objects.
This took a long time comparatively,
which was reflected in items with built-in longevity
and relatively high per-unit cost.
Even the best made goods were
inconsistent in shape and usually unique.
Each part or component of a finished product
had to be carefully hand shaped or formed to fit together,
even the first automobiles.
Crafts made via the cottage industry
also had a complex distribution system,
as the purchaser of the goods had to go house to house
to deliver raw materials and then come back
to collect the goods for market sale.
The industrial revolution created a massive shift
from industrial craftsman or guilds doing ever aspect
of comprehensive building to machines
doing as much as could be automated
with specialized workers doing repetitive tasks
in centralized locations, factories.
Development of machine tools were important
in the factory boom as factories
increasingly made use of machines
and unskilled repetitive labor
and machine tools aided in making
consistently more accurate parts.
As metallurgy and refineries developed
cheap by reliable iron and steel,
machines started being constructed from metal parts,
which unlike wood-framed machines
were not prone to changing shape
with humidity and temperature.
The invention of interchangeable parts
by Eli Whitney was massively important.
No longer would individual parts of, say, a motor,
have to be machined and shaped to fit other parts.
Near identical parts could be replace,
which meant a less skilled workforce
could assemble parts much more quickly.
As all parts wear, this is extremely advantageous,
because this increases the lifetime of a machine in use.
The idea of spare parts spread
from military usage to other industries,
especially transportation and set the stage
for the age of the automobile.
As machine technology and material technology
continued to advance, Ransom Eli Olds,
the founder of Oldsmobile, invented the assembly line.
Oldsmobile cars were still pretty custom
and expensive at the time, a rich man's curiosity,
so it was still uncommon for people
to own their own vehicles.
That is until Henry Ford streamlined factory technology
by implementing a moving assembly line.
This implementation was inspired by a meat packing plant
and had a massive impact on the entire industrialized world.
His emphasis on what is now known as lean manufacturing,
made his famous car, the Model T,
reliable and affordable for the common person,
whereas previous to Fordism, cars were novelty items
only affordable to the extremely wealthy
and prone to all sorts of maintenance issues.
Ford also had a massive impact
on working standards for the Western world.
The standard work week of 40 hours is based in part
on Ford's emphasis on investing in his workers,
forcing competitors to improve wages
and working conditions to keep up.
Around the same time celluloid was developed
as the first reliable plastic to replace
the ivory in billiard balls.
While it could be shaped and formed easily,
a major downside is that celluloid is extremely flammable,
making it unusable in applications
where it might come into contact with heat.
Less flammable plastics were developed for use
in film reels and were labeled safety films.
A semi-synthetic plastic, casein,
was developed using milk proteins for use
in buttons, buckles, and fountain pens.
Casein has a lustrous pearlescent sheen,
but deforms under the curing process.
So products made from casein
were generally machined after curing
and suffered from some splintering effects.
The first truly synthetic successful plastic, Bakelite,
was developed using formaldehyde by Leo Baekeland.
Bakelite was originally designed
for use in composites with natural fibers,
but was later used on its own for use
in heat-resistant applications like phone and radio casings.
Chemists and inventors continue producing
more diverse and specialized plastics,
emphasizing or de-emphasizing
certain characteristics for use
in ever evolving applications.
The interdependent development of machine technology
and material technology continues to grow
in leaps and bounds.
The primary focus being the fastest,
cheapest way to produce things.
This emphasis on cost efficiency sometimes
fails to take into account the products end of life.
Many materials take thousands of years to biodegrade,
which is a necessary even for
extremely long product lifetimes.
In addition, most sources of synthetic plastics
rely on unsustainable fossil fuels,
which we will run out of.
Some companies are making a point of including
sustainable principles in material acquisition,
production, and closed loop cycles,
while new materials and methods are developing all the time.
My hope is that we can develop plastics
and other composite materials that perform
extremely well during the product lifetime,
but afterwards can be easily broken back down
into the production stream reducing waste.
Lastly, the industry knowledge developed
from naturally occurring formable materials
and metal casting had a major impact
on the development of plastics manufacturing.
For example, fluid flow, shrinkage,
and temperature control all have
metal to plastic correlation.
Other design specifications, like material thickness,
post processing, and most importantly bivalve,
or two part molding production of plastics,
would not have been made possible
without developments in metal technology.
In short, current manufacturing technology
combines our composite human knowledge
of chemistry, machinery, interchangeable parts,
assembly lines, and user needs.
Some traditional methods of moldmaking and casting
are still used today and be combined with the advantage
of modern materials and methods.
Take a minute and think about what's better in your life
due to some fantastic plastic?