Manufacturing

Question 1

Wet layup

Answer 1

Layers of dry fabric placed on a mold and resin is brushed or sprayed on

Pros:
Large parts
low tooling cost

Cons:
Labor intensive
Uniformity difficult to maintain

Question 2

Prepreg lay-up

Answer 2

Prepeg is preimpregnated fiber-reinforced material.

Pros:
High fiber volume fraction
Unidirectional material possible
Uniform fiber distribution
Simplified manufacturing

Cons:
Labor intensive
More expensive to cure
Added cost of prepreg
Thermoset prepregs have limited shelf life

Question 3

Vacuum Bag Molding

Answer 3

Uniform pressure before curing–removes excess resin

Stack of prepreg plies is set on the tool surface and covered with a film of flexible, heat resistant material

Question 4

Autoclave processing

Answer 4

Autoclave is a pressure vessel that permits application of a higher pressure than a vacuum bag alone.

Question 5

Filament winding

Answer 5

Filament winding wraps a continuous reinforcement of resin-impregnated fibers onto a mandrel, producing a helical pattern.

Pros:
Automated process-low labor cost
Large parts

Cons:
Limited to axisymmetric parts
Void content may be high without the use of an autoclave

Question 6

Resin transfer molding (RTM)

Answer 6

Resin injected into a mold that contains a fiber preform. Mold is heated to cure the resin.

Pros:
High quality
Good surface finish
Large parts

Cons:
Expensive mold
Limited fiber volume fraction

Question 7

Pultrusion

Answer 7

A continuous process for creation of shapes of constant cross section (like extrusion).

Pros:
Low cost–one step
Good for large quantity of parts

Cons:
Limited shapes