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問題一覧
1
Can a fabricated part be damaged while separating from a mould?
yes, they can be damaged
2
What are 2 ways to prepare a mould surface before applying release agents?
1. buffing 2. polishing
3
What is the purpose of a mould release agent?
used so the part comes off the mould easily after curing. can be sprayed, brushed, wiped on
4
Which one below is a release agent?
1. WAX “most common”, room temp only, use rag and buff 2. Poly vinyl alcohol “leaves slight texture, must be polished 3. Parting film “solvent resistant” dissolves in water, won’t shrink
5
Name 3 examples of release films used to prevent the part curing to the vacuum bag.
1. perforated “allows air and volatiles out of the lay up, prevents bleeder from sticking to the part of repair 2. Parting film “solvent resistant, parting agent for polyester or expoxy resin, will not shrink” 3. peel ply “will stick to laminate, but will pull away without difficulty”. protective layer that peels away 4.solid release film
6
Which is the main purpose gel coats are used for?
1. structural “not common for structural use” 2. cosmetic “void filling” 3. protection from water/uv “protects from water egress”
7
Where would you find ply orientation/sequencing for a layup
drawing
8
Why is ply orientation and sequence important when performing a layup?
to achieve proper amount of strength of the part in correct directions
9
What is the purpose of de-bulking?
compacting / squeezing out air between the plies under moderate heat and or vacuum prevents wrinkles, promotes adhesion
10
Is the de-bulking process the same as preparing a final bag for curing? If not, state one difference.
de-bulking required when laying up complex or heavy section components: post cure wrinkles, squeegee, vacuum bag “is the compacting or squeezing out of air and volatiles between plies or prepreg laminates under moderate heat and vacuum. PREVENTS WRINKLES, promotes ADHESION
11
In a sandwich panel construction, if the skins are pre-cured, what material are used to bond them to the core?
film adhesives
12
What does a sandwich honeycomb panel construction (i.e. floor board) consist of?
two relatively thin face sheets bonded to a relatively thick light core
13
What type of curing process is the most accessible in terms of equipment required?
room temp cure
14
Pre-preg materials can be cured at room temperature?
false, they can’t be cured at room temp
15
Why create layup tooling/templates for pre-preg layups?
help with repeatability, takes less time
16
Name some techniques for impregnating fabric with resin
1. brush 2. squeege 3. roller 4. vacuum assisted
17
What is the purpose of weighing fabric?
to find the correct amount of resin mix needed to impregnate material
18
A resin system has to be uniformly cured to meet design parameters.
true, uniform cure is essential
19
Why do heating devices need to be controlled?
so the correct amount of heat can be applied to the part curing
20
What is placed on curing parts to monitor temperature?
thermocouple
21
If the ambient temperature is too cold can it affect a room temperature cure?
yes, can affect room temp cure
22
What are the 3 main segments of a cure cycle?
1. ramp up, soak, ramp down
23
How do thick tools or caul plates affect curing?
1. supports part during curing 2. leaves smooth finish 3. more uniform heated area (hot monitor)
24
What is it called when a temperature stays constant?
thermal arrest
25
What is the purpose of tap testing a composite structure?
detects delamination or disbond in composite structure
26
List some examples of damage that can be found using visual inspection.
1. scorch 2. dent 3. abrade 4. stain 5. penetrate 6. chip
27
NDT inspections and personnel are regulated by Transport Canada?
true, regulated by transport Canada
28
List 2 advanced trimming tools and techniques:
1. Laser 2. water jet
29
Should you use waterjet equipment to cut a honeycomb sandwich panel? why or why not?
no, would contaminate honeycomb core.
30
What trimming tool leaves a high-quality surface finish by meeting, vaporizing, burning or blowing a jet of gas?
laser
31
Why are respirable fibres dangerous?
capable of being taken in by breathing, reaches deepest part of the lungs
32
what is the most commonly used release agent?
wax
33
different types of core materials
1. balsa 2. foam 3. honeycomb 4. aluminum 5. fibreglass 6. nomex
34
are most honeycombs anisotropic or isotropic?
anisotropic
35
most common wood in composite sandwhich structure?
balsa
36
most common material used for aircraft honey comb
nomex/korex
37
what tools are required for visual inspection ?
light source, magnifying glass
38
is tap testing better on thick or thin composite material?
thin, less than 4 plies