14 - Material Handling

Question 1

What is the purpose of a joggle in sheet metal work?

Answer 1

To produce a flush fit at a metal joint.

Question 2

When caustic soda is applied to a metal and it turns black, what metal is indicated?

Answer 2

Duralumin.

Question 3

What process is required to remove a scratch from a sheet of metal?

Answer 3

Burnishing.

Question 4

When dimpling a sheet of metal, what tooling is required?

Answer 4

A male and female die.

Question 5

Which aluminium alloy is normally used for aircraft skin manufacturing?

Answer 5

2024 aluminium alloy.

Question 6

What is the mold point in sheet metal fabrication?

Answer 6

An imaginary point from which real base measurements are provided.

Question 7

What are relief holes?

Answer 7

Holes drilled in the corner of a metal box to prevent cracking.

Question 8

What is defined as the “setback” in a bend?

Answer 8

The distance from the mold point to the bend tangent line.

Question 9

What are faying surfaces?

Answer 9

Surfaces that are in contact with each other.

Question 10

In sheet metal bending, how should the bend radius be measured to calculate the bend allowance?

Answer 10

Measure to the inside of the bend radius.

Question 11

When using a squeeze dimpling tool, what must be done to accommodate different material gauges?

Answer 11

Adjust the jaws to accommodate different material gauges.

Question 12

In sheet metal bending, what does “bend radius” refer to?

Answer 12

The inside radius.

Question 13

Why is aircraft skin joggled?

Answer 13

To provide smooth airflow at faying surfaces.

Question 14

What does the application of zinc chromate between faying surfaces do?

Answer 14

Inhibits dissimilar metal (electrolytic) corrosion.

Question 15

If caustic soda turns a non-ferrous metal black, what metal is it?

Answer 15

Duralumin.

Question 16

What is used to aid marking out on ferrous metals?

Answer 16

Copper sulphate solution.

Question 17

How is the sight line on a sheet metal flat layout (for bending in a cornice or box brake) measured?

Answer 17

One radius from the bend tangent line that is placed under the brake.

Question 18

When copper sulphate is used on a magnesium alloy, what is the observed effervescence?

Answer 18

It effervesces to a black colour.

Question 19

If bend allowance tables are unavailable, how can the neutral axis of a bend be determined?

Answer 19

By adding approximately one‑half of the stock thickness to the bend radius.

Question 20

What is the formula for setback for a 90° bend?

Answer 20

(R + T).

Question 21

When caustic soda is applied to the edge of alclad, what colour sequence appears?

Answer 21

White – black – white.

Question 22

For marking on a light alloy, what is used and then removed after bending?

Answer 22

A pencil is used to mark the material, and all marks are removed after bending.

Question 23

How can corrosion be inhibited when assembling metals of different potentials?

Answer 23

By applying zinc or barium chromate and assembling while wet.

Question 24

In a mechanical drawing, what type of line is normally used to represent an edge or object not visible to the viewer?

Answer 24

A medium‑weight dashed line.

Question 25

When a piece of metal is bent, what is the state of the metal on the outside of the bend?

Answer 25

In tension.

Question 26

What is the sight line of a bend?

Answer 26

One radius from the tangent line.

Question 27

What is referred to as the minimum radius of bend?

Answer 27

The minimum radius of bend.

Question 28

What are scribers used for?

Answer 28

To mark guide lines on material.

Question 29

What is a hole drilled at the intersection of two bends in a fabricated sheet metal component called?

Answer 29

A relief hole.

Question 30

What does dissimilar metal diffusion bonding provide?

Answer 30

High strength and brittleness.

Question 31

How can marking out on stainless steel be clarified?

Answer 31

With copper sulphate.

Question 32

When drawing lines on aluminium alloy sheet prior to bending, what should be applied?

Answer 32

A thin coat of zinc chromate primer, ready for pencil lines.

Question 33

After solution treatment of aluminium alloy, what effect does immediate refrigeration at –15°C to –20°C have?

Answer 33

It suspends natural ageing for a limited period.

Question 34

What does diffusion bonding and superplastic forming provide?

Answer 34

High stiffness and high ductility.

Question 35

In a composite repair lay‑up, how much should each layer extend beyond the layer below it?

Answer 35

1–2 inches.

Question 36

To enable a composite panel to dissipate static charge, what should it be sprayed with?

Answer 36

Aluminium paint.

Question 37

After completing a bonded honeycomb repair using the potted compound repair technique, which non‑destructive test is used to check the repair’s soundness?

Answer 37

Metallic ring test.

Question 38

Which non‑destructive testing technique is suitable for inspecting delamination in Redux bonded light aluminium alloy structures?

Answer 38

Ultrasonic.

Question 39

Why is an extra layer of fibreglass added to a composite repair?

Answer 39

To increase the strength of the repair.

Question 40

How can electrostatic charges on fibreglass surfaces be reduced or removed?

Answer 40

By treating the surface with a special conductive paint.

Question 41

Prior to aluminium alloy bonding, what surface treatment is used?

Answer 41

Acid etch.

Question 42

How are glass reinforced panels bonded?

Answer 42

With special conductive paint.

Question 43

Which solvents can be used to clean tools used for fibreglass repairs?

Answer 43

Acetone or MEK.

Question 44

Why is chopped strand mat considered a good general-purpose mat?

Answer 44

It gives equal properties in all directions.