- [Instructor] So I've talked about
core definitions for prototyping.
And now I'm going to talk about some of the types
of mass manufacturers that design methodology is applied to.
I'll come back to these types of production
after you've got a solid understanding
of procedural breakdowns and design considerations
for prototyping.
The applications discussed in this chapter
are CNC carving, vacuum forming, compression molding,
injection molding, 3D printing, rotational molding,
and blow molding.
CNC is short for computer numeric control.
Specifically, a CNC router,
which is a subtractive manufacturing method,
where a carving head follows computer code,
carving incremental layers out of your material.
This is extremely useful in creating mold cavities
or forms for other production methods and standalone pieces.
The most common configuration of a CNC is three axis.
Three axis means that the carving head
can move in both X and Y to carve flat patterns,
but, also, up and down, in the Z axis,
allowing for the creation of undulating forms
and multi-depth cavities.
With the power of CNC, you can also carve rotational forms
on a lathe for accurate revolve surfaces.
Even cooler is a five axis CNC,
which allows for movement beyond three axis
by having the workpiece able to move and rotate
in sync with the cutting head.
Which can even cut at an angle.
This articulation of movement allows for the workpiece
to be manipulated at angles closer
to what a human hand could sculpt,
except with the powerful precision of computer calculations.
5 axis allows for more complex cutting operations.
Another form of production is vacuum forming.
Vacuum forming is a one-sided type of thermoforming
that is often combined with the CNC master
which the plastic is formed over.
Vacuum forming works by heating thin sheets of plastic
with open faced oven coils,
until it reaches the correct pliability.
Once the plastic has reached the right temperature,
it's stretched over a master form
with vacuum and downward pressure.
There's a short period of cooling
so the plastic will hold the form it's taking.
And then it's removed to repeat the cycle.
The plastic creates an eggshell-like layer
over the geometry it's copying.
This production method
is commonly used in blister packaging.
A way to position and display products for sale
by sealing them in.
Press forming,
also called press molding or compression molding,
is just what it sounds like.
A heated two-part mold squishes material into its final form
with high pressure until it's cured.
Material to be press formed comes in raw,
granulated material, pre-made sheets,
or pliable putty blobs called charges.
Once a material has solidified,
it's removed with injector pins.
A common-used example of this process
would be rubber shoe outsoles.
Injection molding is a major form
of plastic casting manufacture
that requires a minimum of two mold halves.
The B side remains in place,
while the A side is clamped shut during the curing cycle
and opened for part removal.
During the process cycle,
pellets are fed into the top of the machine,
where they melt in the heated cylinder.
The cylinder contains a long, rotating screw
that stirs the pellets as they melt into liquid form.
Once a plastic is the right temperature,
it's injected with forceful pressure into the mold.
Ideally, filling it exactly where it cools in the mold
until it's ready to inject.
Injection molding machines often use temperature control
built into the dye, to make sure the entire mold
is the right temperature for each part of the process.
The machine uses injector pins
to pop the parts out of the mold, into a bin,
where they wait for the next part of production.
Injection molding has a fairly quick cycle time,
depending on the part being made.
Enabling it to make hundreds or more parts a day.
Because you can make so many parts quickly,
unit price is lower.
The savings per unit contrast the high upfront tooling cost
of making the initial dye,
starting at around 10,000 US dollars.
3D printing is an additive manufacturing method
wherein plastic, guided by computer code,
is formed layer slice by layer slice
to create a final model.
I'll go over a couple of different ways this can happen.
The first of which is FDM,
short for Fused Deposition Modeling.
In FDM, plastic filament
is pulled through a heated extruder head,
following a pattern generated by the computer,
depositing incremental layers.
These layers are created by depositing
the heated plastic filament.
Each layer very slightly overlapping the last.
This overlap helps create lamination
or bonding between the layers,
so that your final print is relatively solid.
3D printing can sometimes require support geometry,
due to gravity, utilizing generated support structures
that need to be broken off after printing.
Sometimes a separate filament support material
is extruded at the same time.
That could be dissolved away after the print is complete.
Another method of 3D printing,
creating similarly sliced additive layers,
are resin cured printers.
Which cure liquid plastic
with highly concentrated laser light.
After each layer is deposited,
the platform syncs a specified increment
so the process can be repeated.
With their layers combining to a complete geometric volume.
These prints could also require support structures.
Both kinds of printers can create high resolution prints
with very small incremental layers, measured in microns,
tiny fractions of a millimeter.
I'm particularly excited about development
in LED cured resin plastics.
Which would bring this technology even closer to home.
More specific information on 3D printing
can be found in the LinkedIn Learning Library.