I will be heating a carbon fiber composite in an autoclave. The carbon fiber will be per-impregnated with Mgs 335 and 340 hardener. The autoclave technician wants to know the temp, pressure ramp, dwell and cool down cycle. I haven’t had a clue what the necessary cycles are all I know is that the best cure temp for 335 is 176 degrees.
Is surface quality an issue? Is the part still in the mould? Is the mould able to take 176 degrees (or more). Is vacuum still on?
In general, ramp with 10 C / hour up to the desired temp, then keep it there for a certain amount of time, after that allow to cool naturally.
I checked the datasheet, and 176F is scaringly close to the ultimate Tg of 82 degrees. I would not suggest a freestanding postcure at that temperature.
To answer your question’s, no surface finish is not a problem. The part is still in the mold yes the mold will be made of carbon fiber. What would you suggest for this process and resin system?
I would ramp with 10C/h to 70 degrees C, then dwell for at least 18 hours. Let cool off (naturally, not forced) to 45-50C before demoulding.
If the mould can have 120C, you could ramp to 100, then dwell for 5 hours. Leave vacuum on if possible.
I haven’t tried to do an elevated cure for a laminating RT resin before. Normally they HAVE this information. You might want to try and call them, see what they recommend. A normal 3-5f/min ramp sounds good, but dwell time and temp matter due to possible exotherming. Don’t want it too high all of a sudden, but you don’t want to take forever. Maybe a slow ramp, and then dwell at 120f for several hours, and then up to 350 for several more hours might work.
I was under the impression he was looking for a post cure cycle. If you want to cure (from wet to solid) in the autoclave, then games are different. You do not want an enormous exotherm. Definately install a thermocouple on the part.
Not sure why you would need an autoclave for a postcure 
You are right. But over here a company mis-uses it for everything.
For a postcure a box and a lamp are the minimum. From there it goes onwards…