Three Main Stages Of The
Production Of A Machined Part
Casting, Forging, Welding
Drilling, machining, surfacing
The assembly of parts
The Casting Process
First a pattern is made.
Then a cavity is made by placing a pattern in
Next molten metal is poured into the cavity of
The Casting Process
The rough casting is now ready for the machine shop.
Holes are then bored and reamed.
Top and bottom surfaces are machined
Smaller holes will be drilled and counterbored.
All corners on cast parts are fillets and rounds.
Forging is produced by using heavy mechanical
presses or hammering heated bars of metal
Advantages of forging over sand casting are that
forged parts are much stronger and less brittle.
Welding is the fusion or joining of
two pieces of metal by means of
heat, with or without the application
Metals are classified as:
Ferrous - contain iron and steel.
Nonferrous - do not have iron content
(such as copper and aluminum).
Alloys - mixture of two or more metals.
Inorganic Materials Include:
• Carbon and graphite - have low
tensile strength (ability to be
• Ceramics are clay and glass
materials. (resistant to heat,
chemicals, & corrosion).
Annealing – is the process generally used
to soften metal by heating followed by slow
Hardening – requires heating and then
rapid cooling in oil or water.
The plastics industry represents one of the
major manufacturing segments.
Thermoplastic – becoming or remaining
soft and moldable when subjected to heat.
Thermosetting – becoming permanently
hard and unmoldable when once subjected
Used in the production of
bottles, automotive ductwork,
hollow toy components, and
Used to manufacture products such
as housings for electronic
implements, automotive components,
food storage containers, and
components for medical applications.
Used in the manufacturing of thin-walled
packages for the food industry.
Manufactured primarily by injection molding.
CAD in Manufacturing
The process of developing a design drawing on a
CAD system and producing it on a computerized
machine is called CAD/CAM.
The process of converting the CAD drawing into a
preprogrammed, coded instructions is called
Computer Numerical Control (CNC).
The advantages of the (CNC) is, better production and
control, increased productivity, decreased labor and
lower production costs.
The Machinist Steel Ruler
Commonly used measuring tool for getting
rough measurements on a part.
The smallest division on the fractional
scale is 1/64” (.016).
Decimal, fractional, or
Often used by drafters
to record dimensions
from a machined
prototype or part.