Pore surface - prepreg

General Composites Discussions Composites Talk
#1

REFER PICTURES

Type of Material

Carbon 922-1 TENAX HTA (Carbon Graphite), FM300 Surfacing Film

Type of Material (Mould)

Steel

Bagging Sequence

Laminate > Solid release film > breather Ultraweave > bagging film

Curing recipe (Autoclave Cure)

1.Apply full vacuum (22 inHg @ 74.5kPag minimum).
2.Apply pressure to 500±10 kPag (72.52±1.45 psig) and begin heat up.
3.Vent vacuum to the atmosphere as a part of the pressure cure cycle, when the autoclave pressure is between 103.42 kPag – 137.89 kPag (15 – 20 psig).
4.Heat up to 179±5°C at a rate of 2±0.5°C/min. Heat ramp rates only apply when lagging thermocouple achieve 48.88°C (120°F). Heat ramp shall be between 25-225 minutes.
5.Dwell for 120 – 300 minutes at 179±5°C. Dwell temperature is achieved when lagging temperature achieve minimum dwell temperature (minimum 173.8°C).
6.Cool down at a rate 2±0.5°C/min.
7.Release pressure when the lagging thermocouple decreases to 65.6°C (150°F).

PLEASE HELP ME ON THIS. HOW TO ELIMINATE THIS POROUS SURFACE ON CURVATURE :confused:

#2

Since they appear on edges only, it’s a matter of poor local compaction.
Put more care when laying the material, or make more intermediate debulks if the laminate stack is thick.
Or use local pressure intensifiers.

#3

as what Roberto said, looks like bridging. Make sure you debulk Layer ONE on the mold, and then, say ever 3-5 layers, depending on the ply amount.
Make sure it’s pushed in perfectly. Intensifiers help sometimes, but only if you do it right fro mthe start.

#4

We use silicone pressure intensifiers to help with corners like this. As riff says, you definitely need to do a proper debulk sequence.

Also, how does your bag look? You should have a nice pleat running down the line there. Worst comes to worst, buy some silicone and make a caul to help with the compaction there.