Free CCT Repair Techniques & Quality Control Questions and Answers — Questions and Answers
Question 1: What is the recommended method to prepare a damaged composite surface for repair?
- Sanding and cleaning (Correct answer)
- Painting directly
- Applying glue without preparation
- Ignoring surface condition
Correct answer: Sanding and cleaning
Proper surface preparation is critical for a successful composite repair. Sanding removes any damaged material, old coatings, and creates a roughened surface profile that promotes good mechanical adhesion for the new repair materials. Following sanding, thorough cleaning removes dust, oils, and contaminants, ensuring a clean, bondable surface for optimal repair strength and longevity.
Question 2: Which type of resin is commonly used in composite repairs?
- Epoxy resin (Correct answer)
- Polyethylene
- Polypropylene
- PVC
Correct answer: Epoxy resin
Epoxy resin is widely favored for composite repairs due to its excellent adhesive properties, high strength, low shrinkage during curing, and good chemical resistance. It forms strong bonds with various reinforcement fibers and substrates, making it ideal for restoring the structural integrity of damaged composite components. Its versatility and performance make it a go-to choice for professional repairs.
Question 3: What is the purpose of post-curing a composite repair?
- Improves mechanical strength (Correct answer)
- Reduces strength
- Softens the repair
- Increases porosity
Correct answer: Improves mechanical strength
Post-curing involves exposing a composite repair to elevated temperatures for a specific duration after the initial cure. This process further cross-links the polymer matrix, significantly enhancing the material's mechanical properties such as strength, stiffness, and heat resistance. It ensures the repair achieves its full design performance and durability.
Question 4: Which equipment is used to check repair thickness?
- Ultrasonic thickness gauge (Correct answer)
- Caliper
- Microscope
- Ruler
Correct answer: Ultrasonic thickness gauge
An ultrasonic thickness gauge uses sound waves to measure the thickness of a material from one side. It transmits an ultrasonic pulse into the material and calculates the thickness based on the time it takes for the pulse to reflect back from the opposite surface. This non-destructive method provides highly accurate measurements for checking composite repair thickness against specifications.
Question 5: What quality control technique checks for surface defects?
- Visual inspection (Correct answer)
- Radiography
- Ultrasonic testing
- Thermography
Correct answer: Visual inspection
Visual inspection is a fundamental quality control technique that relies on the human eye, often aided by magnification or specialized lighting, to detect surface defects. It can quickly identify issues such as cracks, scratches, delaminations, porosity, or improper finish on the surface of composite materials. This method is cost-effective and typically the first step in assessing material quality.
Question 6: Why is proper mixing ratio important in resin repairs?
- Ensures proper curing (Correct answer)
- Increases drying time
- Changes color only
- Reduces viscosity
Correct answer: Ensures proper curing
The proper mixing ratio of resin and hardener is critical because it dictates the precise chemical reaction required for complete curing. An incorrect ratio can lead to incomplete polymerization, resulting in a repair that is soft, brittle, tacky, or lacks the desired mechanical properties. Adhering to manufacturer specifications ensures the composite material achieves its intended strength and durability.
Question 7: Which PPE is necessary during sanding of composite repairs?
- Respirator mask (Correct answer)
- Gloves only
- Safety glasses only
- Ear plugs only
Correct answer: Respirator mask
Sanding composite repairs generates fine dust particles, including glass or carbon fibers and resin particulates, which can be hazardous if inhaled. A respirator mask is essential Personal Protective Equipment (PPE) to filter these airborne particles. It protects the worker's respiratory system from irritation, sensitization, and potential long-term health issues, serving as a primary defense against inhalation hazards.
Question 8: What does quality control ensure in composite repairs?
- Repair meets standards (Correct answer)
- Delays repair
- Reduces quality
- Increases costs unnecessarily
Correct answer: Repair meets standards
Quality control in composite repairs involves a systematic process of monitoring and verifying that all repair procedures and materials conform to specified standards and requirements. Its primary goal is to ensure the repaired component performs as intended, is safe, and meets all design and regulatory specifications. This minimizes defects, ensures reliability, and maintains the integrity of the composite structure.
Question 9: Which environmental factor can affect composite repair quality?
- Humidity (Correct answer)
- Temperature only
- Wind
- Light intensity
Correct answer: Humidity
Humidity can significantly affect composite repair quality, especially with moisture-sensitive resins. High humidity can interfere with the curing process, leading to incomplete polymerization, reduced bond strength, and increased porosity. It can also cause moisture absorption in some materials, compromising the repair's long-term durability and performance.
Free CCT Repair Techniques & Quality Control Questions and Answers
What is the recommended method to prepare a damaged composite surface for repair?