Self Study Flashcards

1
Q

What are sliding bearings?

A

Bearings where two surfaces move relative to each other without benefit of rolling contact.

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2
Q

What does a shaft do?

A

the component rotates and transmits power from a driving device through a machine

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3
Q

What is Turning and Boring used for?

A

To machine internal and external surfaces of components with rotational symmerty

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4
Q

7 Turning/Boring operations

A
Turning
Facing
Parting off
Boring
Drilling
Form Cutting
Thread Cutting
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5
Q

In Turning what is the swing?

A

The maximum diameter of work which can be rotated

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6
Q

Typical accuracy of turning and boring?

A

0.01 mm but is dependent on material and diameter

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7
Q

How does milling take place?

A

The workpiece is clamped to a movable table and the tool is rotated about either a vertical or horizontal axis

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8
Q

What is milling?

A

Multiple point cutter removes metal normally to create a flat surface although free form surfaces can be created using computer and numerical control

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9
Q

Accuracy of milling

A

typically 0.05 mm but depends on the size and material being machined

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10
Q

What is drilling and reaming used for?

A

Create blind of through holes by cutting process.

Holes are drilled in rough machining and reaming gives the final finish to achieve close tolerances

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11
Q

Explain the process grinding

A

Abrasive material removal which is generally a finishing process. It is only suitable for hard materials

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12
Q

Typical accuracy of grinding

A

0.005mm

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13
Q

Why do discontinuous chips occur?

A

The material fractures ahead of the tool, indicating a poor choice of cutting condition

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14
Q

3 things about continuous chips

A
  1. Represent the ideal cutting for ductile materials
  2. Results in long tool life and good surface finish
  3. Very long chips can be dangerous and difficult to handle so chip breaker are often employed to break the chip up, this reduces the chance of injury and makes the chips easier to dispose
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15
Q

5 reasons coolants area used

A
  1. to reduce friction
  2. to reduce the tool/work temperature
  3. to wash away chips
  4. to inhibit corrosion
  5. to reduce built up edges on tools
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16
Q

4 desired characteristics of cutting tools

A
  1. have high hardness
  2. be tough
  3. have excellent abrasion resistance
  4. be able to withstand high pressures
17
Q

What is high speed steel used for and why?

A

single point tools and twist drills
mostly in job shop type environments where productivity rats are not high.
HSS retains its hardness up to 600C

18
Q

3 things about cast alloy tips

A

can be brazed or mechanically fastened to a holder
normally a high cast alloy which produces very hard carbides can retains its hardness up to 900°C
they are cast in ceramic mould because the material is difficult to machine

19
Q

4 Things about cemented carbide tips

A

Sintered from powder
Retains hardness up to 1000°C
Less brittle than cast alloy tips
commonly used where high production rates are required

20
Q

Define the clarification of task

A

functions and constraints are documented in a detailed design spec

21
Q

Define conceptual design

A

involves the establishment of function structures in the search for solution principles and their combination into design variants

22
Q

Define embodiment design

A

determines the layout and forms and develops the artifact in accordance with technical and commercial considerations

23
Q

Define detail design

A

lays down the final form, arrangement, dimensions and materials of all individual parts
manufacturing instructions are produced

24
Q

What are the elements of a design specification

A
Requirements
constraints
criteria
context of use
open remarks or questions
25
Q

Define abstracting

A

ignoring what is particular or incidental and emphasizing what is general and essential

26
Q

4 reasons the weighting an rating method bad?

A
  1. subjective and arbitrary
  2. numerical answers can be given too much importance. the number implies a precision that isn’t there
  3. the multiplication makes the method sensitive to small changes
  4. users an become good at making sure the rating give the answer they want
27
Q

What is shearing?

A

when a shape is cut from sheet metal by shearing the sheet between a punch and die

28
Q

Difference between punching and blanking

A

Punching the slug is discarded

Blanking the slug is retaining

29
Q

5 types of shearing operations

A
Parting
perforating
notching
slitting
lancing
30
Q

What do grip rings do?

A

improve the finish on the edge of a blanked part

it prevents movement of the sheet and allows the clearances to be reduced whilst producing a very smooth edge

31
Q

Three problems with sheet bending?

A

minimum bend radius
springback
bending forces

32
Q

define the minimum bend radius

A

the smallest radius which the sheet can be bent to without tensile fracture occurring on the outside of the bend

33
Q

Typical values of the minimum bend radius

A

when t is the thickness it varies from 0 to 6t