Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Machining > Turning And Hole Making > Flashcards

Turning And Hole Making Flashcards

1
Q

Common lathe cutting operations

A

Turning
Facing
Cutting with form tool
Boring
Drilling
Cutting off
Threading
Knurling

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Factors involved in turning operations

A

-Workpiece and tool material
-surface finish and dimensional accuracy
-characteristic of machine tool

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Tool geometry

A
    • Rake angle improve cutting operations by reducing force and temp but result in small included angle of tool tip
  • too high relief angle = tip likely to chip off
  • too low relief angle = more flank wear
  • cutting edge affect chip, strength and cutting force
  • nose radius affect surface finish and tool tip strength
  • ## smaller nose radius, rough surface, low strength. Large nose radius lead to tool chatter
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Material removal rate

A

A = f*d
A is x sectional area
f is distance tool travel per revolution
d is depht of cut

MMR/rev = A* travel = pi * Davg* f*d
Travel is average circum
D is avg diameter = (D0+ Df)/2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

MMR and rotational spd

A

Rotational spd of workpiece = n
MMR = piDfdn =dfv
Tool travel rate = f*n
Cutting time, t= l/fN

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Force in turning

A

Cutting focre
Thrust force
Radial force

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Turning formula

A

Surface spd V = pi D n (ori for max)
Feed f = mm/rev or rpm/mm per min
P= uMRR (u is specific energy)
Torque = p/w (w=2piN)
Fc = 2 torque/Davg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Lathe component

A
  1. Bed - support all major components
  2. Carriage - an assembly of cross slide, tool post and apron
    -Cross slide - moves radially in and out
    -Tool post - with a compound rest that swivel for tool positioning and adjustment
    -Apron - allow manual and mechanized movement of carriage and cross slide
  3. Headstock - have hollow spindle that allow workholding to be attached. Bars or tubing can be fed to be undergo turning operations
  4. Tailstock - equiped with center that can be fixed or free to rotate with workpiece. Drill can be attach to drill axially into workpiece. Quill - cylindrical part with tapered hole.
  5. Feed rod and lead screw - rotates during lathe operations and moves the carriage and cross slide.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Lathe specification

A

Swing (diameter of workpiece)
Distance between centers (Headstock to tailstock)
Length of bed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Lathe Workholding device (Chucks)

A

Have 3-4 jaws (3 for round 4 for block/odd shape/heavy stuff)
3 are geared scroll and 4 are independent chuck. Jaw can be reversed.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Chucks selection factor

A
  1. Type/spd of op
  2. Workpiece size
  3. Production and accuracy requirements
  4. Jaw force requirement
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Lathe Workholding Device (collet)

A

Alternative to chuck.
Longitudinally split tapered brush
Tapered surface shrinks radially and tighten the workpiece
Advantage - grip entire circumference, best for part with small cross section

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Lathe Workholding device (face plate)

A

Clamp irregular shaped workpiece. Have holes allowing workpiece to be bolted/clamped

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Lathe Workholding device (Mandrel)

A

Can be placed inside hollow/tubular workpiece. Allow both cylindrical and end faces to be machined. Only cylindrical surface.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Lathe support

A

Theres steady rest and follow rest. Prevent part deflection from cutting force. Steady rest directly clamp directly on the ways of the lathe, follow rest clamped on the carriage and travel with it.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Boring/drilling (lathe operations)

A

Drilling - workpiece is clamp in workholder whereas drill bit is clamped on the tailstock where it advanced toward the workpiece.
Boring can be performed in the drilled hole to be improved.

17
Q

Type of lathe

A

Special purpose lathe
Tracer lathe
Automatic lathe
Automatic bar machine
Turret lathe
CNC lathe

18
Q

Turret lathe

A

Can do multiple operation
Several cutting tool mouted on hexogonal main turret which rotate for each specific operation

19
Q

CNC lathe

A

Equipped with ATC, automatic tool changer. Reliable in repetitive op maintaining dimension accuracy and require less skilled labor .

20
Q

Factor for Surface finish and dimension accuracy during turning op

A
  1. Characteristics and conditions of machine tool
  2. Stiffness
  3. Vibration and chatter
  4. Process parameters
  5. Tool geometry and wear
  6. Cutting fluids
  7. Machinability of workpiece material
  8. Operator skill.
21
Q

Design consideration before turning op

A
  1. Part should be designed so they can be fixtured and clamped in workholding with ease.
  2. Dimensions accuracy and surface finish should be as wide as possible
  3. Avoid sharp corner, tapers and major dimensional variation
  4. Blanks should be as close to final dimensions as possible.
  5. Part design should allow cutting tool to travel along workpiece smoothly
  6. Use available standard cutting tool
  7. Material chosen according to machinability.
22
Q

Guideline for turning operations

A
  1. Minimize tool overhang (minimize vibration)
  2. Support workpiece rigidly
  3. Use machine tools with high stiffness/high damping capacity
  4. If tool begins to chatter, modify one of the process parameters.
23
Q

Troubleshoot for turning process

A

Tool breakage - tool material toughness, tool angle, tool stiffness, worn bearing/components, machine parameter too high.

Tool wear - machining parameter too high, improper tool material, cutting fluid, improper tool angle.

Rough s f - build up edge on tool, feed too high, tool too sharp, chipped or worn, vibration/chatter.

Dimensional variability - machine/workholding stiffness, temp, tool wear

Tool chatter - lack of stiffness of machine tool/workholding, excessive tool overhang, improper parameter

24
Q

Screw nomenclature

A

Refer to pg56 chp 23.

25
Q

Design considerations for screw threading

A
  1. Undercut termination before shoulder.
    2.chamfer at the ends
  2. Thread section should not be interrupted with slots, holes.
  3. Use standard thread inserts
  4. Min engage length of fastener should be 1.5x its diameter
  5. All cutting op in one setup
26
Q

Type of drill

A

Space drill, straight flute drill, drill wtig indexable carbide inserts, drill with brazed carbide tip, gun drill, trepanning.

27
Q

Troubleshoot for drilling

A

Drill breakage - dull drill, drill seizing cuz by chips clogs in flutes, feed too high, lip relief angle too small.
Excessive drill wear - cutting spd too high, fluid, too high rake angle, drill burned/strength loss from sharpening.
Tapered hole - drill misalignment/bent, lips not equal, web not central.

Oversized hole - same as above, loose machine spindle, side force in workpiece.

Poor hole surface finish - dull drill, fluid, improper alignment, improper ground drill

Machining (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions