2106 - MIDTERMS Flashcards
Most manufacturers of composite structures augment the strength of the finished product by applying ___________ and
_________to the matrix/fiber mix as it cures.
heat and pressure
is a manufacturing process that uses a male and female mold. The reinforcing fabric is wetted with a matrix or pre-preg materials. It was laid into a female mold and the male mold is used to form the shape of the part
COMPRESSION MOLDING
With this technique the object which is to be cured is placed into a plastic bag and the air is evacuated, pressure is applied to the component by surrounding components
VACUUM BAGGING
is widely used because of the manufacturing benefits which include low materials cost, accuracy, automation, and repeatability.
FILAMENT WINDING
This is an automated process in which tapes (unidirectional prepregs) are laid over a mandrel and compressed into place.
FIBER PLACEMENT
is a relatively simple and low cost automated method of manufacturing composite components.
PULTRUSION
is a manufacturing method that uses a two part mold with the dry fabric laid into the mold.
RESIN TRANSFER MOLDING (RTM)
is a manufacturing technique that is simply laying prepreg material by hand into a mold.
WET LAY-UP AND HAND LAY-UP
units were designed for repairing composite components when an oven or autoclave wasn’t available.
HOT BOND EQUIPMENT
It senses the temperature of the part and relays the information to the controller or monitor.
THERMOCOUPLE
Ovens offer controlled, uniform temperature over all surfaces.It is often used in the manufacturing process to cure many parts at the same time.
OVEN CURING
This is an alternative method for curing repairs when the contour of the part does not allow the use of a heat blanket.
HEAT GUNS
The purpose of applying mechanical pressure is to:
-Remove the excess resin from the components, ensuring the proper ratio of resin to fiber reinforcement. As the resins cure, they start to flow. The pressure will squeeze out some of the excess resin.
-Remove air trapped between layers.
-Maintain the contour of the repair relative to the original part.
-Hold the repair securely, preventing any shifting of the patches during the curing process.
-Compact the fiber layers together.
are used for metal working. Use Bossing Mallets, Pear-shaped mallets or rounded plastic mallets to shape metal curves, fenders and/or bowls.
SHOT BAGS
Is placed on one side of the repair and it allows air to flow through it and through the vacuum valve, and it is used to prevent it from sealing itself by sticking to the area to be repaired .
BREATHER
Bag is sealed properly. After the Vacuum is drawn on a part, the vacuum hose is disconnected for about two minutes.
VACUUM LEAK CHECK
The material commonly used for vacuum bagging come in a number of types, depending on the manufacturer, and how the repair is to be performed.
VACUUM BAGGING MATERIALS
used to cover the component and seal out air. They must be made with absolutely no voids or pin holes.
VACUUM BAGGING FILM
Needed to create the airtight seal to close the bagging film either to itself or to the flange of your mold, enabling your vacuum to work.
SEALANT TAPE
Frequently inside the vacuum bag, so that your part can be pulled away from the bagging materials once they are complete.
RELEASE FILM
A nylon or polyester release fabric may be used next to the wet resin during the curing operation to transfer excess resin to the bleeder material without sticking to the part.
PEEL PLY
It provides both heat and pressure under extremely controlled conditions. They are normally used for manufacturing.
AUTOCLAVES
These are used to cure composite parts for many years. But these are no longer recommended. To help monitor temperature, use a temple stick or other temperature-monitoring device.
HEAT LAMPS
These are probably the most widely accepted form of applying heat to a composite component for repair work.
HEAT BLANKETS
Widely used in the manufacture and repair of aluminum-skinned aircraft, it is used to temporarily fasten multiple sheets of material together before the pieces are permanently joined
CLECO
Use for holding fabric in place prior to gluing or holding several pieces of sheet metal or wood together.
SPRING CLAMP
are cotton like absorbent materials used to soak up excess resin.
BLEEDERS
are cottony materials that allow air to flow through a valve or over the surface of a part throughout the vacuum bagged area.
BREATHERS
Composite matrix systems cure through chemical reaction
between a catalyst and resin. Some matrix system require heat to cure the composite to achieve maximum strength , while others cure at room temperature but can be accelerated by applying
external heat.
METHODS OF CURING
Room Temperature Curing
Some repairs may be cured at room temperature
(65°F to 80°F) over a time span of 8 to 24 hours.
It can be accelerated by applying low heat (140°F to
160°F).
Full cure strength can be achieved within 5 to 7 days.
This method is normally performed on parts which
are lightly loaded or nonstructural parts
The most widely accepted method of
curing structural composites employs resins
that cure only at higher temperatures.
Heat Curing
utilizes a flexible silicon heating-blanket that incorporates a temperature control.
This is the preferred method of curing, due to the
controlled even heating of the part. Most hot patch
bonding machines also incorporate a vacuum pump to
apply pressure during the curing process.
Hot patch bonding
A more sophisticated and accurate curing process may be
accomplished using a programmable controller.
Ramp and soak
