TEAM ILC-CANOPY CLOSURE COVER- REPORT FILE

Mohammad Ahmad Muheeb Paul Iskandar Liu Yang

CANOPY CLOSURE COVER

A.M.P.A.S

INTEGRATED TEAM PROJECT

TEAM I.L.C


Contents

Introduction ............................................................................................................................... 3

Specification and Requirement .................................................................................................. 4

Process Definition ...................................................................................................................... 5

Part Design ................................................................................................................................ 7

Mold Design and Manufacturing ................................................................................................ 8

Manufacturing Step Description .............................................................................................. 10

Manufacturing Part Results ..................................................................................................... 15

Cost Evaluation ........................................................................................................................ 16

Improvement Strategies .......................................................................................................... 16


Introduction

Canopy closure cover is used to hide the canopy closure mechanism in the interior of aircrafts by DynAero.

The part is mounted on the fuselage by 4 screws and there are 2 holes on the part (as shown in the pictures

below). It is used for all the Ultralight Aircrafts. Cost of each part 40-50€. Number of parts produced per

year is approximately 40.

The part is available on both sides, as it is a cosmetic part it doesn’t carry any loads. Therefore no stress-

strain analysis were made and a random lay-up of different prepreg layers can be done.

Originally DynAero manufactured the part by using a conventional method by doing a manual lay-up and

applying the resin using a roller. The new part was manufactured by using Preimpregnated Carbon Epoxy

fabric.


Specification and Requirement

The requirements specified by DynAero were as follows:

▪ The part must have enough rigidity to sustain accidental impacts.

▪ Weight of the part should be reduced by at least 20%.

▪ Cost of manufacturing should be reduced by 10-15%.

▪ Final product surface should be good and cosmetically attractive.

▪ Development of a CAD file for the part and the mold.

NOTE: There are no load requirements for this part.


Process Definition

The raw materials used for the manufacturing of the new part are as follows:

1. Release film

2. Preimpregnated fabric Carbon Epoxy 5626 1808 S 50

3. Peel ply

4. Perforated release film

5. High temperature breather fabric

6. Vacuum bag

7. Sealing tape

Equipment used for the manufacturing of the new part are as follows:

▪ Vacuum pump

▪ Oven

▪ Portable trimmer

▪ Air pump

For protection the following personal protective equipment was used:

▪ Protective glasses

▪ Gloves

▪ Lab coat

▪ Trimming gloves

▪ Face mask

Material description:


The material used for the manufacturing of the part is Preimpregnated fabric Carbon Epoxy 5626 1808

S 50. It is a twill weave fabric with 0˚ and 90˚ orientations of 5626 carbon fibers with 1808 epoxy resin.

Mass surface of the Preimpregnated fabric is 400 g/m2 and the mass of the resin is 50% of the total

mass. Density of the resin at 20˚C is 1.18 g/cm3 and the glass transition temperature is 128˚C. The

conservation duration of the Preimpregnated fabric is one month if stored at 20˚C and one year if stored

at -18˚C. The Preimpregnated fabric is stored in the freezer at a temperature of -18˚C, in order to use it

for the process it must be removed from the freezer 24 hours prior to the manufacturing process being

done and kept at room temperature.

After laying up the all needed layers compaction is applied prior to the curing cycle for 30 minutes to

remove excess air from the lay-up. After compaction is done, the mold with the lay-up is placed in the

oven for a curing cycle which is given by the manufacturer of Preimpregnated fabric in the bill of material.

A further detailed description of how the process is performed is given in the topic Manufacturing

step description mentioned in the report later.


Part Design

As shown in the figure below the original part provided by DynAero was scanned using Digital Image

Correlation (D.I.C) as we can see the resolution quality was very low, to use this file as the new part CAD

file.

Using dimensions extracted from the DIC as a reference, a new CAD file was created but with modified

dimensions which were later approved by DynAero. As shown in the figure below the flanges were extruded

to simplify the manufacturing process of the part and later the mold.


Mold Design and Manufacturing

Using the new CAD file created for the part, a male mold CAD file was generated using the same dimensions

and shape as the thickness of the part being manufactured is less than 0.5 mm.

The design for the mold was modified in order to have an easy demolding after curing. A fillet of radius 4

mm was given on the part of the mold where the Preimpregnated fabric is going to be laid up on the all the

top sides of the mold and the flange was given a draft angle of 95˚.


This CAD file was sent to NIMITECH for manufacturing of the mold. The mold was manufactured using

RenShape® BM 5055 blank with a density of 0.72-0.75 g/cm3, a maximum operating temperature of 140˚C

and deformation resistance up to 40 MPa.

The following are the properties of the mold material:

It has a very smooth surface.

Ease of manufacturing and machining.

Good dimensional stability.

The following are the applications of the mold material:

Draping tools for preimpregnated fabrics.

Vacuum forming molds


Manufacturing Step Description

Preprocessing of the mold

Firstly, we need to prepare the mold surface to prevent it from sticking to the prepreg after temperature

curing cycle. There are several methods to do this, including application of release agent or release film or

high temperature wax.

For our process we use a release film for the ease of demolding of the part, we use tape to stick the release

film to the mold and in order to avoid the wrinkling of the release film, as it might influence the inner surface

quality of parts.

Applying prepreg layers

Three layers of preimpregnated fabrics are laid up on the mold for the final part. The first ply is laid up after

removing the protector film on one side and the ply is laid up, then compaction is applied on the

preimpregnated fabric manually to give it the shape of the final part overlapping is done at corners and

excess material is cut off. Then the protective cover is removed so that the next layer of preimpregnated

fabric is laid up. This process is repeated for the second and third layer.


Applying the other necessary layers

The other layers are applied in the following sequence:

1. Peel ply (allows free passage of volatiles and excess resin during cure)

2. Perforated release film (allows migration of excess resin

3. Breather Fabric - High Temperature (provides means of applying vacuum and assist in removal of

air and volatiles from the whole assembly)

4. Vacuum Bag (provides a sealed bag to allow removal air)


Applying vacuum bag and vacuum

After all the necessary layers are laid the vacuum bag is placed on the mold. As the vacuum bag is applied

on the profile of the mold pleats are created at the corners to provide homogeneous compaction of the part.

The vacuum bag is check for leaks and if there are no leaks then the compaction with vacuum is applied for

30 minutes at 2 bars pressure before placing the mold in the oven for curing.

Curing cycle inside oven


The curing cycle is set as per the bill of material provided by the manufacturer. The curing cycle is set to

be at 120˚C for 75 minutes with a ramp rate of 3 ˚C per minute.

After the curing cycle is done the part is allowed to cool down at room temperature.

Demolding

For demolding the layers are removed in the following sequence:

1. Vacuum bag

2. Breather fabric

3. Perforated release film

4. Peel ply

To make demolding further easier by using an air pump to pump cool air between the part and the mold.


Mechanical trimming

The demolded part is marked for the profile by using the original part and then machined by using a

portable abrasive rotary blade trimmer.


Manufacturing Part Results

Parameters Original New

Weight 108 gm 58 gm

Layers 2 3

Price 40-50 € ≈30€

Thickness 1.38 mm 0.83 mm


Cost Evaluation

Recurring Cost

Material Quantity Price

Preimpregnated fabric 0.2 m2 10€

Yellow gasket 0.5 roll 4€

Vacuum Bag 0.3 m2 7.2€

Peel ply 0.1m2 0.5€

Release film 0.1m2 0.6€

Perforated release film 0.1m2 1€

Breather fabric 0.1m2 1€

Non Recurring Cost

Tool Quantity Price

Valve 1 10 €

Mold 1 500 €

Furnace 1

Vacuum Pump 1

Improvement Strategies

▪ To further reduce the weight of the part a layer of Preimpregnated fabric can be reduced and

reinforcements like stiffeners can be added.

▪ The places where holes are drilled an extra layer can be added to provide more strength and rigidity.

▪ To reduce cost, scrap pieces of the Preimpregnated fabric used to manufacture other parts can be

used for the manufacturing with overlapping of two or more pieces.

Documents

TEAM ILC-CANOPY CLOSURE COVER- REPORT FILE