Transcript Chapter 7
Chapter 7
Technological Systems
and
Production Tools in Technology
Production Tools
► Change
the shape of materials to make
them useful for human needs
► Help in the creation of artifacts. Objects
made by human activity.
► Are created and maintained by humans
► Are used to make our lives easier
► Social problems can be created by tools???
Material Processing
► Tools
and Machines
► Changes the form of materials
► Tools were used to cast, form, and machine
materials into specific shapes
► Tools also can be used to help assemble
products and apply protective or decorative
coatings
Machine Tools
► Machines
used to make other machines.
► The elements of machine tools include
What type of tool is it???
►Single
or Multiple Point Cutting Tool
What type of cutting motion is implemented???
►Rotating,
Reciprocating, or Linear
What type of support is used to machine the
stock???
Cutting Tools
► Cutting
actions require a cutting tool
► Cutting tools must be harder than the material
being cut
► Needs sharpened edges, relief angles, and rake
angles
Sharpened edges cut the material
Relief angles keep the tool sides from rubbing against
the material
Rake angles create a chip which allows waste materials
to be carried away
Types of Cutting Tools
► Single
Point Cutting Tools
Contains a cutting edge on the end or along the
edge of a rod, bar, or strip
► Examples:
Chisels
Hand Planes
Knives
Types of Cutting Tools (cont.)
► Multiple
Point Cutting Tools
Series of single point tools arranged on a
cutting device.
Can be arranged in a set or random pattern
► Examples:
Saw teeth are in a set pattern
Abrasive paper and grinding wheels do not
contain a set cutting arrangement
Motion
► Cutting
Motion
The action that causes material to be removed
from the work
► Feed
Motion
The action that brings new material into the
cutter
► To
complete a cut both motions need to
happen simultaneously
Motion (Cont.)
► Cutting
and feed motions can be:
Rotating: Uses round cutters or spins the work
around an axis
Linear: Moves the cutter or work in one
direction along a straight line
Reciprocating: Moves the tool or work back and
forth or up and down.
Support
► The
tool and work piece must be supported for
proper operation.
► Types of cutting and feed motions determine the
type of support needed.
► Rotating motions: Require a holder that will
revolve around an axis.
► Reciprocating motions: The blade is clamped at
two ends within the machine. The blade moves
back and forth or up and down and cuts on one
movement of the saw blade.
► Linear motions: Lathes use tools that are
clamped in a holder or held on rest. Band Saw
Support (Cont.)
► Reciprocating
motions: The blade is clamped at
two ends within the machine. The blade moves
back and forth or up and down and cuts on one
movement of the saw blade.
► Linear motions: Lathes use tools that are
clamped in a holder or held on rest. Band Saw
blades travel around two wheels while the material
is supported by the machine table.
Six Categories of Machine Tools
► Turning
Machines
► Sawing Machines
► Drilling Machines
► Shaping Machines
► Planing Machines
► Grinding Machines
Turning Machines
► Turning:
Process in which a workpiece is
held and rotated on an axis.
This process is completed on machines called
lathes.
Lathes produce their cutting motion by rotating
the workpiece.
The feed motion is generated by linear
movement of the tool.
Lathe
► Precise
machine tools used to machine
wood, metal, and plastics.
► Contain four main parts:
Headstock: Contains the machine’s power unit.
Tailstock: Supports the opposite end of a part
that is gripped at the headstock.
►The
headstock and tailstock are attached to the bed
of the lathe
Lathe (Cont.)
Tool rest or holder: Support the tool. On metal lathes
the tool rest is clamped into position and is fed into or
along the work. Wood lathes contain a flat tool rest
where the operator moves the tool by hand.
► Work
ways.
can be held or clamped into place in two
Between centers
► Live
Center: Rotate with the workpiece
► Dead Center: Work rotates around the device
Within the headstock
Lathe Operations
► Turning:
Cutting along the length of the
workpiece.
► Tapering: Cutting along the length of a cylinder at
a slight angle to produce a cylindrical shape with a
uniformly decreasing diameter.
► Facing: Cutting across the end of a rotating
workpiece to produce a square end.
► Grooving: Cutting into a workpiece to produce a
channel with a diameter less than the main
diameter of the workpiece.
Lathe Operations (Cont.)
► Chamfering:
Cutting an angled surface between
two diameters on the workpiece.
► Parting: Cutting off a part from the main
workpiece.
► Threading: Cutting threads along the outside
diameter or inside a hole in the workpiece.
► Knurling: Producing a diamond pattern of grooves
on the outside diameter. This produces a gripping
surface.
Sawing Machines
► Use
teeth on a blade to cut material to a
desired shape and size.
► Three basic groups of saws include:
Circular Saws
Band Saws
Scroll Saws
Sawing Machine Cutting
Operations
► Crosscutting:
Reducing the length of a material
► Ripping: Reducing the width of material
► Resawing: Reducing the thickness of material
► Grooving, Dado, Notching: Cutting rectangular
slots on or across a part
► Chamfering and Beveling: Cutting an angled
surface between two primary surfaces of a
material.
Circular Saws
► Use
a disk shaped blade with teeth
arranged around an edge.
► Three types of circular saws:
Table Saw
Radial Saw
Chop Saw
Table Saw
► Uses
a linear feed motion
► Workpiece is pushed into the rotating blade.
► The operator controls the rate of speed that
the workpiece runs through at.
Radial Saw
► The
rotating blade moves across the
workpiece
► The workpiece is positioned stationary on
the saw table bed
Chop Saw
► Used
to cut narrow strips of material to length
► The blade is attached to a pivot arm assembly
► The blade assembly is pivoted in a downward
motion to produce the cut
► Can create angled cuts
► The sliding compound miter saw was created of
the chop saw and the radial saw.
Band Saw
► Uses
a blade made from a continuous band
or strip
► The saw uses a continuous linear motion
which generally travels around two wheels
to perform a cut
► Come in two styles:
Vertical
Horizontal
Scroll Saw
► Uses
a straight blade with teeth on one
edge
► The blade is clamped or pinned into the
machine at one or most commonly at two
ends.
► This machine operates off the reciprocating
motion.
Drilling Machines
► Drilling:
produces or enlarges holes using a
rotating cutter.
► The drill is moved into the work with a feed
arm. This is the feed motion.
► The rotating cutter head produces the
cutting motion.
► Two common types:
Stationary
Portable electric
Drilling Operations
► Drilling:
Producing straight cylindrical holes in a
material
► Counterboring: Producing two holes around the
same center point. The outer hole has a larger
diameter than the inner hole.
► Countersinking: Producing a beveled outer portion
of a hole.
► Reaming: Enlarging the diameter of an existing
hole.
Common Drilling Tools
► Twist
Drills: shafts of steel with flutes along
the shaft and points on the end to produce
a chip
► Spade Bits: Flat cutters on the end of a
shaft
► Forstner Bits: Two lipped cutters that
produce a flat bottom hole. The are used
for counterboring operations in
woodworking.