Phenolic Composites Manufacturing - Autoclave Cure
Phenolic Composites Manufacturing - Autoclave Cure
(OP)
We are currently evaluating the possibility of curing a phenolic-carbon and phenolic-aramid hybrid laminate in an autoclave versus the ovens that we typically run phenolic parts in.
I have heard of horror stories of the phenolic gasing causing vent lines and equipment to "clog up" over time needing replacement. I have also heard that there are certain techniques/equipment that can alleviate the issue. We don't seem have this issue with our oven cured phenolics.
Does anybody have any experience curing phenolic materials in an autoclave and can shed some light on the subject?
Thanks in advance!
I have heard of horror stories of the phenolic gasing causing vent lines and equipment to "clog up" over time needing replacement. I have also heard that there are certain techniques/equipment that can alleviate the issue. We don't seem have this issue with our oven cured phenolics.
Does anybody have any experience curing phenolic materials in an autoclave and can shed some light on the subject?
Thanks in advance!





RE: Phenolic Composites Manufacturing - Autoclave Cure
What do you expect to achieve by switching from oven to autoclave?
RE: Phenolic Composites Manufacturing - Autoclave Cure
The specific phenolic-carbon prepreg material we are purchasing hasn't been cured in the oven at our facility but we do a high volume of phenolic-aramid and phenolic-polyesters all under vacuum bags.
This is a new design part that the customer would prefer us to switch our epoxy-aramid/carbon autoclave cured design to a phenolic-aramid/carbon and retain the autoclave cure (due to toxicity/flamability/etc). Although we don't feel that the autoclave cure is necessary as this is an interior non-structural part, we still want to comply with the customer request but want to adjust as necessary given any additional issues the phenolic autoclave cure may bring.
Also, for the autoclave cure we are going to be investing in permanent bagging since this is a high turn part. Do you see this causing any issues?
Thanks!
RE: Phenolic Composites Manufacturing - Autoclave Cure
In autoclave cured phenolics the condensation products (e.g., water) are usually trapped in composite and will slowly dry out after cure. You have to be very careful with post cures done soon after initial cure because the steam pressure can blow parts apart.
Reuseable vacuum bags will be a challenge. Phenolic resins are very corrosive to most bagging materials like nylon and silicone. You will need to use teflon barrier films to protect your bagging films. The fumes of phenolic resin can penetrate barrier films and attack bagging films after several cycles.
RE: Phenolic Composites Manufacturing - Autoclave Cure
RE: Phenolic Composites Manufacturing - Autoclave Cure
Void content may be reduced by increased autoclave pressure to counteract the vapour pressure of the volatiles.
RE: Phenolic Composites Manufacturing - Autoclave Cure
We do replace/maintain our vacuum system filters/fittings/etc regularly so it seems that we shouldn't have any issues more than what we deal with now.
Again, thank you!