20XX- Question 7 Flashcards Preview

HL LC Engineering: Every Machining question Ever [2017-2010] > 20XX- Question 7 > Flashcards

Flashcards in 20XX- Question 7 Deck (11)
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1

Identify any two lubricating materials used in engineering machines

PTFE

Oil

Grease

Graphite

2

Distinguish between the use of a plug gauge and the use of a gap gauge

Plug gauge determines if a hole is within a specific range of limits

Gap Gauge checks if external diameter is within a specific range of limits

3

State two uses for a chuck guard on the lathe;

Protects user from cutting chips and swarf

Protects user from rotating chuck

Keeps hair and clothing away from the lathe

Has a viewing window which allows you to safely monitor machining

Interlock guards will prevent the machine turning on when not in place

4

Distinguish between countersink and counterbore holes;

Countersinking is making the hole bigger so countersunk head screws sit flush with the surface of the piece

Counterboring is making the diameter of the hole bigger so a cheese head screw sits flush with the surface of the piece

5

Name two important properties of cutting tool materials.

Must be harder than the material being machined

Must retain a sharp edge at high temperatures

Must be able to be sharpened or replaced easily

Must be able to withstand shock loads from the machining process

6

Describe, with the aid of a suitable diagram,
a surface grinding process for a cylinder head.

Surface Grinding

A metal cutting process which produces smooth surfaces

The grinding wheel rotates and cylinder head is fed to and fro consistently

the table is moved across the wheel by a small amount at the end of each stroke

The grinding wheel can be lowered to take a new cut.

7

Outline two safety hazards associated with using a grinding machine

Tools and metals must be gripped tightly

Loose clothing may get trapped

Needs to be mounted correctly to avoid vibration

Eye protection is needed as small metal pieces are emitted at a high speed

8

Identify the metal cutting chips shown at A and B and distinguish clearly
between them making reference to material properties. A=continuous chip B=Discontinuous chi[

A – Continuous chip
Soft, ductile material e.g. aluminium

B – Discontinuous chip
More brittle materials e.g. Brass

9

Analyse the impact on safety and surface finish of the chip formation shown at C. Built up edge

As the built-up edge gets bigger, the cutting edge will not cut well

The surface finish will deteriorate and machining will not be smooth.

The machine will excessively vibrate

10

Give two advantages and two disadvantages of
CNC machining.

Advantages:
Allows for mass production
Multi tool loading for complex components
Produce parts to maximum accuracy

Disadvantage:
More expensive to purchase and repair.
Higher maintenance than manual machining
Doesn't eliminate the need for expensive tools

11

Identify two factors to be taken into account
when selecting CNC machining for the
manufacture of the chess pieces shown opposite.

Choice of material to make the pieces

• Size of the pieces

• Amount of pieces to be made in the set

• Design shape and detail.