- [Instructor] Let's go a little deeper
into our understanding of production.
I will now define important core concepts
that inform the overall design considerations
for mold making in this course.
These terms are repeatability,
efficiency, quality, and tolerances.
I'll define them in terms of manufacturing,
with a few examples to illustrate my point.
I'll be using SOLIDWORKS throughout this course
to help illustrate the concept under discussion,
but I must state that my goal is to create models
that can be opened in any number of CAD programs
for a three-dimensional understanding of my topics.
The first concept that we'll be going over is repeatability.
Repeatability means production of the same part
over and over again in a circular cycle,
the opposite of unique artisanal goods.
A repeatable manufacturing process
copies the initial shape again and again,
using the same geometry for each copy.
If it is not repeatable, the design must be updated.
The technical definition of efficiency
is the ratio of the use of work
performed by a machine or in a process
compared to the total energy expended or heat taken in.
An efficient manufacturing process
utilizes all available resources and technology
to produce as many acceptable parts
in as little time as possible,
using the least amount of raw materials and energy.
But what does that mean to you?
In prototyping, this translates
to the optimal use of time and materials available,
eliminating wasted material, time, and cost
to reach the end product goal.
Quality is the conformance to the standards set
by either the industry producing the work
or the consumers of the work, but usually both.
Quality is also defined as a ratio of value to cost.
Does the product create enough value to the user
to be worth the cost of purchasing it?
There are ways to improve the perceived quality of a product
by paying special attention to users' wants and needs,
where certain traits would be considered added value.
It would be impossible to describe them all
within the context of this course,
but there is a specific example
that helps examine this metric.
Something that I am assuming you have all handled before
is a business card.
Beyond its graphic design, what does it feel like?
What are the edges like?
What's the texture and the weight of it?
Does it feel cheap?
Embossing, textures, punches, gloss, and color
are all quite unnecessary
to the utilitarian purpose of a business card,
but they can all contribute to a feeling of quality.
Last but not least, tolerances.
Tolerances refers to the margin of error
and slight variations allowed per part.
Those parts that succeed
in fitting within that strict margin are used,
with those parts outside tolerances discarded.
Parts must be engineered with tolerance in mind
so that the mass majority of part A
will fit with the mass majority of part B.
Most products are combinations of multiple parts,
which will need to fit together in numerous ways.
The tolerance of snap-fits, hinges,
enclosures, moving parts, and material combinations
all need to be built into the design.
A great example of this would be plastic building sets.
Each brick has to fit with every other part
with just the right amount of resistance
to hold them together and just enough give
that the user can continue to break them apart
and build them back together thousands of times
in different variations.
These core concepts are in this particular order
because each definition is dependent on the one before it.
You must first define what you want and need to repeat.
Then you must engineer
how to accomplish the process most efficiently.
After that, you must hold your process
to a standard of quality.
Your standard of quality is measured
by your allowable tolerances.
All of these are essential in manufacturing.