Machining Operations Flashcards
week 9 - 10 (68 cards)
1
Q
is machining good for mass production
A
no
2
Q
Rotational Vs. Nonrotational (prismatic)
A
rotational: cylindrical or disk-like shape
nonrotational: block-like or plate-like shape
3
Q
Further machine operation and part geometry classification
A
- Generating - part geometry determined by feed trajectory of cutting tool
- Forming - part geometry is created by the shape of the cutting tool
4
Q
In generating Shape the __________ of the cutting tool determines the shape
A
moment
5
Q
In forming the __________________ determines the shape
A
shape of the cutting tool
6
Q
what machine is used for the turning operation
A
a lathe
7
Q
flat turning /turning is
A
reducing the diameter (single-point cutting tool)
8
Q
Lathe specification
A
1.size designation
- length of bed
- max distance b/t centers
- swing (max diameter that can be rotated on lathe)
2. max RPM
3. horse powe
9
Q
bed of a basic lathe
A
– Foundation of the
lathe
– Supports all other
major components
– Top part has two
ways
10
Q
head stock of a basic Lathe
A
- fixed
- mounted on the ways
- consists of
- hollow spindle
- bearings
-motors, pulley and belts or transmition gears to drive spindle
11
Q
Carriage of basic lathe
A
Along with the apron—
provides the base for
mounting and moving
cutting tools
12
Q
cross slide of basic lathe
A
Mounted to the carriage
and provides movement
for facing and cut-off
operations
13
Q
Compound rest of basic lathe
A
- Mounted to the cross
slide. Can rotate for angle
cuts.
– the component that holds
the tool post for cutting
tools.
14
Q
tail stock of basic lathe
A
- Supports the other end
of the workpiece - Lower portion of casting
fits inner ways - Can slide along the
ways
15
Q
feed rod of basic lathe
A
provides forward and reverse motion for carriage and cross slide
16
Q
lead screw for basic lathe
A
– Used for threading
purposes.
– Engages with the
half-nut to provide
correct feed for
specific lead of
thread.
17
Q
4 methods of holding the work peice in lathe
A
- holding the work between center
- chuck
- collet
- face plate
18
Q
holding the work between two centers
A
- one in head stock called dog
- stock-cone shaped point (live center turns and doesnt have heat, dead center does not turn and produces heat
19
Q
when is holding the work between centers used
A
when part has large length to diameter ratio
20
Q
holding work peice using chuck
A
- quick and easy to hold work peice
- 3 jaws for circle, 4 for square or multi for other shapes
- dont need a tail stock to use
21
Q
when are chucks used
A
for parts with low length to diameter ratio - no tail stock
22
Q
work holding collets
A
- holding device has to match size (custom design)
- better than chucks bc more accuracy and holding power
23
Q
work holding face plate
A
- hold parts with irregular shapes
- custom designed
24
Q
Types of Lathes (turning machines)
A
- Engine
- Toolroom (small, more acurate)
- Turret ~ cutting tool moved quickly manually
- Automatic (chucking) ~ same as turret
- Automatic bar machines ~instead of chuck a cullet is used
- screw machine - make screws
- multiple screws - makes multiple tools
25
basic hole making processes acount for approx _________
50- 60 % of all metal removal processes
26
what does the flute of a drill do
- allow coolant to flow to the cutting-edge
- move chips from cut zone
27
3 main components of a drill bit
- Shank
– Body
– Point
28
what are the 3 standard pint drill geometry angles
1. conventional (118* for soft metals)
2. long angle point (60-90* for non-ferrous materials)
3. flat angle point (135* for harder metals)
29
Work holding for drill presses can be claimed in any of the following:
– Vise - general purpose work holder with two jaws
– Fixture - work holding device that is usually custom-designed for the particular work part
– Drill jig – similar to fixture but also provides a means of guiding the tool during drilling
30
reaming (type of drilling)
enlarges hole its not boring because it gives a good surface finish
31
tapping (type of drilling)
Used to provide internal screw
threads on an existing hole
(its rpm is same as feed)
32
Countersinking
tapered feature at the end of a hole
- used for flat head screws
33
Counterboring
Enlarging of an existing hole at one end.
- used for head screws
34
Spot facing
Smoothing, squaring, and/or flattening a surface (lets it touch end of hole if the shape is rounded)
35
Upright Drill Press
- good service finish
- motion is limited
36
Radial Drill Press
- allows for more motion (rotates in and out)
- not good accuracy in tolerance
37
Drill Tapping Machines
makes threads
38
Drill Multi spindle
allows for multiple workpieces at once
39
Turret Drill Press
multiple cutting tools but u can only operate on one work piece
40
explain rotation in milling
- TOOL is rotating
- axis of rotation is perpendicular to feed
- multiple cutting edges
41
What are the two types of milling
1. Peripheral milling (aka plain milling)
2. Face Milling
42
What is peripheral milling
cutter axis parallel to the surface and cutting edges on the outside periphery of the cutter
43
what is face milling
cutter axis is perpendicular to the surface being milled and cutting edges on both the end and outside periphery of the cutter
44
What is peripheral - slab milling -
cutter width extends beyond the workpiece on both sides
45
What is peripheral - slotting -
width of cutter is less than workpiece
width, creating a slot in the work
46
variations of peripheral milling
- teeth to the side - slide milling
- two cutting teeth- straddle milling
- more than two teeth - gang milling
- cutting through entire thing- slitting
- form or shape milling
47
explain face milling
- axis of rotation perpendicular to work piece surface
- milled surface is flat and has no relation ship to the cutter
48
Face milling variations
- partial facing
- end milling
- surface contouring
49
what is face milling - end milling -
it's to the side (not side milling that's for peripheral)
50
what is face milling - profile milling -
outside periphery (boundary) of a
flat part is cut
51
what is face milling - Surface Contouring -
Ball-nose cutter fed back and forth across work along a curvilinear path at close intervals to create a three dimensional surface form
51
what is face milling - pocket milling -
used to mill shallow pockets into flat parts
52
Conventional milling feed direction
(spins clockwise, fed left to right)
- ship is thinnest at the start
- less "shock" to cutter
- less vibration and chatter
- lifts the workpiece up (not efficient for thin samples)
53
Climb milling feed direction
(spins clockwise, fed right to left)
- chip is thick at the start
- results in more shock to cutter
- more vibration and chatter
- holds work against table (can machine thin parts )
- better surface finish
54
knee and column milling machine
moves parallel in z axis and if head is rotated x axes
(looks like a human)
55
Bed mill - horizontal spindle
used for heavier and larger materials
56
milling operations - 4th axis
usually rotary - the tool or the work (on x or 2 axis) this expands the possibilities
57
Mill-turn centers
one or both of the work piece or tool has to be rotatating
58
Shaping and planing
LINEAR MOTION (NO ROTATION)
SINGLE POINT CUTTING TOOL
Shaping (feed provides work, speed is by tool)
Planning (feed provides speed, speed is by work)
59
Broaching
in a single stroke, u get the final finish BUT u have to custom-make the broaching tool
- good surface finish and tolerance
- expensive, good for high volume
60
Circular saws
used for linear shapes
61
Band saw
– Irregular shapes
– Very versatile
– Profile cuts
– Internal cuts
– external configurations
62
Hack saw
linear reciprocating motion of hack saw blade
63
High speed machining (surface speed is faster)
1. faster production rates
2. shorter lead times
3. reduce costs
4. better finish
64
what is DN ratio
(bearing bore diameter{mm})(max spindle speed - RPM {rev/min})
Between 500,000 and 1,000,000
65
What is HP/RPM Ratio
hp/rpm ratio = horspower/max spindle speed (RPM)
66
how to define High speed Machining (HSM)
- DN ratio
- HP/RPM Ratio
– Higher production rates
– Shorter lead times
– Rather than functions of spindle speed
67
requirement for high speed machining
* "look ahead", helps avoid "undershooting" and "Overshooting" tool path
* Balanced cutting tools, toolholders, and
spindles to minimize vibration
* Coolant delivery systems that provide
higher pressures than conventional
machining
* Chip control and removal systems to cope
with much larger metal removal rates
