CCT CCT Curing Processes & Autoclave Operations 1 — Questions and Answers
Question 1: What is the primary purpose of an autoclave in composite manufacturing?
- To mix resin and hardener
- To apply simultaneous heat and pressure for curing composite laminates (Correct answer)
- To cut prepreg material to shape
- To store uncured prepreg materials
Correct answer: To apply simultaneous heat and pressure for curing composite laminates
An autoclave applies controlled heat and elevated pressure simultaneously to consolidate and cure composite laminates, producing high-quality, low-void parts.
Question 2: What is the typical autoclave pressure used for curing carbon fiber/epoxy aerospace composites?
- 1 to 5 psi
- 85 to 100 psi (approximately 6 bar) (Correct answer)
- 200 to 300 psi
- 500 or more psi
Correct answer: 85 to 100 psi (approximately 6 bar)
Aerospace carbon fiber/epoxy composites are typically cured at 85 to 100 psi to consolidate plies and minimize void content to meet structural requirements.
Question 3: What does a cure cycle define in composite autoclave processing?
- The color mixing schedule for resins
- The time-temperature-pressure profile followed during laminate cure (Correct answer)
- The number of plies in the layup stack
- The fiber orientation sequence
Correct answer: The time-temperature-pressure profile followed during laminate cure
A cure cycle defines the specific time, temperature, and pressure ramp rates and dwell periods that ensure proper resin flow, consolidation, and crosslinking.
Question 4: What is the purpose of pulling vacuum on the bag during autoclave composite processing?
- To add structural weight to the layup
- To remove volatiles and entrapped air before and during cure (Correct answer)
- To apply extra heat to the laminate
- To prevent discoloration of the surface ply
Correct answer: To remove volatiles and entrapped air before and during cure
Vacuum removes entrapped air and volatiles from the laminate stack before and during cure, reducing void content in the finished part.
Question 5: What is the role of thermocouples during an autoclave cure cycle?
- To measure finished part dimensions
- To monitor part and tooling temperatures and verify the cure cycle is achieved (Correct answer)
- To check resin viscosity during cure
- To measure autoclave internal pressure
Correct answer: To monitor part and tooling temperatures and verify the cure cycle is achieved
Thermocouples attached to the tool and part surfaces monitor actual temperatures to verify the cure cycle is followed and identify hot or cold spots.
Question 6: What happens to epoxy resin viscosity as temperature increases during the initial heat-up phase?
- Viscosity increases immediately as temperature rises
- Viscosity decreases (resin becomes more fluid) before crosslinking begins (Correct answer)
- Viscosity remains completely constant throughout heat-up
- The resin solidifies immediately when heated
Correct answer: Viscosity decreases (resin becomes more fluid) before crosslinking begins
During initial heat-up, resin viscosity drops as temperature rises, enabling resin flow and air/volatile removal before gelation and crosslinking begin.
CCT CCT Curing Processes & Autoclave Operations 1
What is the primary purpose of an autoclave in composite manufacturing?