PROCESS GUIDE LINES:
LAYUP AND CURE OF EPOXY PREPREG
Easycure E-710™ AND Easycure E-710FR™
MATERIALS
160-250F CURING
OVEN/VACUUM PROCESS
48 South Service Road, Suite 300, Melville, NY 11747 / Phone +1.631.465.3600 / Fax +1.631.465.3100 / www.parkelectro.com
TABLE OF CONTENTS
1
2
3
4
Mold Preparation................................................................................... 3
Cutting and Lay-up................................................................................ 3
Debulk Procedure .................................................................................. 3
Bagging Procedure................................................................................. 4
4.1 Recommended Shop Supplies............................................................ 6
5 Cure Cycle .............................................................................................. 7
6 Bag Removal and Part Identification .................................................. 8
48 South Service Road, Suite 300, Melville, NY 11747 / Phone +1.631.465.3600 / Fax +1.631.465.3100 / www.parkelectro.com
1
Mold Preparation
Each mold or lay-up surface shall be cleaned prior to lay-up, using non-contaminating
cleaners, such as acetone or alcohol. Mold preparation shall be performed outside the
lay-up room.
After cleaning, each mold shall be treated with non-contaminating release agents in
accordance with the supplier’s instructions.
Thermocouple quantity and location will be specified on the shop traveler.
2
Cutting and Lay-up
The cutting and lay-up area shall be kept free of contaminants.
If prepreg laminations are pre-cut and grouped into kits for future lay-up and cure, the
poly-film backing provided by PACM shall not be removed until each ply is ready to be
placed in the lay-up mold. Kits shall be stored in sealed, moisture-proof containers until
ready for lay-up.
Upon removal from storage, the prepreg materials shall be allowed to warm to room
temperature inside the sealed moisture-proof bag for at least 3 1/2 hours or until visible
moisture has vanished from the outside of the bag.
Any peel ply requirements will be specified on the drawing and/or shop traveler.
Unless otherwise specified on the drawing, splices are allowed. However, they must
overlap by at least one inch and no two splices in a single ply shall be closer together than
24 inches. Minimum distance between splices in adjacent plies is six inches. Butt splices
are generally to be avoided. If butt splices are used, the maximum gap at any point is
0.030 inches. Butt splices shall have one additional ply of material, the same as the base
laminate, extending for at least one inch on either side of the splice joint.
White, lint-free cotton gloves are required for hand / personal protection. Talc-free latex
or nitrile gloves are acceptable alternates.
No cutting of prepreg materials is permitted on the tool.
3
Debulk Procedure
Debulking shall be performed in order to achieve appropriate compaction. Debulking
shall be performed on the first ply and than additional debulks should be performed every
two (2) plies of prepreg with FAW of 500-900g/m2 or every three (3) plies of prepreg of
FAW of 300-500g/m2 or every five (5) plies of prepreg with FAW 100-300g/m2.
a. Apply one layer of non-porous release fabric over the prepreg lay-up.
48 South Service Road, Suite 300, Melville, NY 11747 / Phone +1.631.465.3600 / Fax +1.631.465.3100 / www.parkelectro.com
b. Apply one layer of 340g/m2 (10oz/yd2) breather (N10 or two layers of N4) on top of
the non-porous release film. If the breather is not contaminated with resin or other
foreign material, the breather may be re-used.
c. Install nylon bagging film over the laminate or form-fit a silicone rubber bag and
edge seal to the tool with vacuum bag sealant; install the vacuum connector through
the bag. Use multiple vacuum connectors so that no point on the part is more than 60
inches from a vacuum source.
Note:
Install the vacuum connectors on the tool surface outside the
perimeter of the laminate wherever possible. Placing the connector in a bag
pleat is an acceptable alternate. In case that the mold is not big enough to
accommodate this type of arrangement you can place the vacuum port on top
of the part by folding the bag and use 4-6 plies of breather.
d. Apply vacuum of at least 25 inches Hg for at least 15 minutes at a rate that does not
cause the prepreg to shift. When specified by the applicable shop traveler, the
laminate may be heated to 100F maximum and held for 10-15 minutes during
vacuum application but there shall be no more than six (6) debulks at 100F on any
lay-up. The final debulk shall be for 30 minutes minimum.
4
Bagging Procedure
The shop traveler will give specific instructions regarding the use of peel plies, bleeder
materials, breather materials and bagging materials.
The general procedure will be as follows:
a. The tool is prepped with the appropriate mold release section 1.
b. Apply the prepreg on the release tool.
c. Apply one layer of peel ply or equivalent the same size as the part.
d. A Bleeder is recommended if the resin content of the prepreg is over 42% or for very
thick part over 0.5” thick. Two plies of 300gsm 7781 of E-Glass fabric or one ply of
610gsm woven roving can be used.
e. Apply one layer on non-porous release film, Teflon or equivalent, over the lay-up;
extending at least 1/2 inch past each edge of the part.
f. Apply one layer of breather fabric over the lay-up ensuring that it forms a path to the
vacuum port.
g. Vacuum sources are preferable not be on the surface of the part.
1) There should be at least two (2) sources for any part larger than four (4) square ft.
For larger parts, at least one vacuum connection should be provided for every 18
square ft. of laminate surface.
2) Where possible, the maximum distance to any point on the laminate surface
should not exceed 60 inches. Protect against clogging with resin by applying
extra breather under the vacuum port.
48 South Service Road, Suite 300, Melville, NY 11747 / Phone +1.631.465.3600 / Fax +1.631.465.3100 / www.parkelectro.com
3) In case that the mold is not big enough to accommodate this type of arrangement
you can place the vacuum port on top of the part by folding the bag and use 4-6
plies of breather.
h. Apply the nylon bagging film and edge seal to tool with vacuum bag sealant.
i. Evacuate the bag to at least 25 inches Hg and adjust the bag to eliminate wrinkles and
bridging.
j. Install a vacuum gauge at the vacuum probe connector. Allow the bagged assembly
to stand for at least 15 minutes with an applied vacuum of at least 25 inches Hg.
Remove the vacuum source and monitor the bag vacuum. Leakage may not exceed
three (3) inches Hg in the first five (5) minutes after removing the vacuum source.
Thermocouple
Vacuum port
8
7
6
5
2
(Optional)
4
3
1
1.
2.
3.
4.
5.
6.
7.
8.
Tool surface
“Tacky tape” rubberized sealant tape
Prepreg laminate
Release film (peel ply porous teflon or equivalent)
Bleeder
0.002” Airtech 234 TFP Non-porous teflon or equivalent
N-10 Airweave breather cloth
0.002” Vacuum bag film
48 South Service Road, Suite 300, Melville, NY 11747 / Phone +1.631.465.3600 / Fax +1.631.465.3100 / www.parkelectro.com
4.1
Recommended Shop Supplies
Item
Acetone
Denatured Alcohol
Release Film
Release Agent
Breather
Bleeder
Peel Ply
Sealant Tape
Silicon Rubber
Bagging Sheet Film
Part No. or Specification
2-propanone (Acetone)
purity 99.5%
Ethanol - min 190% proof
WL4600 (non-porous)
WL5200 (non-porous)
A4000R (non-porous)
A5000 (non-porous)
200 TFNP-Brown Teflon
234 TFNP-Brown Teflon
or Equivalent
Frekote 700
RAM 225
or Equivalent
A-3000
Airweave N10
or Equivalent
7781 woven fiberglass cloth
or Equivalent
200TFP (porous) - Teflon
234TFP (porous) - Teflon
Release Ply B – Nylon
or Equivalent
GS 100
SM5126
or Equivalent
Silicon Rubber minimum
375°F use temperature
or Equivalent
HS6262
WL7400
WL8400
or Equivalent
Supplier
Sun Chemical, Dow, Ashland,
Union Carbide
Ashland, Sofecia, Union
Carbide, Eastman Chemical
Airtech International
Airtech International
Airtech International
Richmond
Richmond
Airtech International
Frekote
Lilly
Richmond Products
Airtech International
JPS Industries Inc.,
BGF Industries Inc.,
Hexcel-Schwebel
Richmond
Airtech International
Airtech International
Circuit Supply
Scnee-Morehead
Airtech International, Inc.,
Richmond Aircraft Products, Inc.
De-Comp Composites, Inc
Richmond Products
Airtech International
Airtech International
48 South Service Road, Suite 300, Melville, NY 11747 / Phone +1.631.465.3600 / Fax +1.631.465.3100 / www.parkelectro.com
5
Cure Cycle
All prepreg materials are to be cured according to tightly controlled time, temperature
and vacuum requirements as shown in Table I. Quality Assurance shall continuously
record time, temperature and vacuum during the cure process.
Thermocouple wires should be used to monitor and record the temperature of
representative test panels. One method is to place the thermocouple junctions at the
laminate mid-plane and near the edge of the laminate where they will be trimmed off
after the panels have been cured. Thermocouples may be placed outside the bag only if it
has been previously demonstrated that there is negligible temperature difference between
the inside and outside of the bag.
The lagging thermocouple will be used to control the curing cycle in all the steps.
a.
b.
c.
d.
e.
Table I
Cure Cycles
Apply full vacuum, 27±2 in Hg
Heat at 0.5 to 3°F/min to 160±5°F
Hold at 160±5°F for 13±0.5hrs
Cool at 5 to 7°F/min to 120°F or below before venting vacuum
Remove from oven when oven temperature is 120°F or lower
You can use alternative curing temperatures based on the table below.
Temperature
160-165°F
170-175°F
180-185°F
190-195°F
200-205°F
210-215°F
220-225°F
230-235°F
240-245°F
Curing Time
13 hours
7 hours
5 hours
3.5 hours
2.5 hours
2 hours
1.5 hours
1 hours
0.5 hour
Tg °F, by DSC
194
203
212
221
225
230
235
240
257
If the application requires maximum thermal resistance the laminate can be post cure
at 250°F (125°C) for 1hr. The post curing can be done unsupported as long as the
weight, the size and the shape of the panel will not introduce a distortion otherwise a
minimal support is required.
PACM’s technical support group can recommend deviations, due to thick parts or high
surface quality.
48 South Service Road, Suite 300, Melville, NY 11747 / Phone +1.631.465.3600 / Fax +1.631.465.3100 / www.parkelectro.com
6
Bag Removal and Part Identification
Before removal of the vacuum bag from the cured part, examine the bag for evidence of
ballooning, charring, rupture, resin contact, tearing or other condition that would indicate
bag failure during the cure cycle. Record any observation of unusual conditions on the
shop traveler. Remove the vacuum bag.
When removing the cured laminate from the tool surface, avoid the use of any sharp
objects or tools that could damage the surface of the part or the mold. Avoid bending the
cured laminate or the detail part. Do not remove any peel ply at this time.
Each part or assembly shall be identified with the respective part number, shop traveler
number and cure cycle number. If multiple parts are made on a single traveler (or Shop
Order, Work Order, etc.) then each individual part shall be assigned a discrete serial
number.
48 South Service Road, Suite 300, Melville, NY 11747 / Phone +1.631.465.3600 / Fax +1.631.465.3100 / www.parkelectro.com