I. Appearance Inspection (Piece-by-Piece)
1. Carbon Fiber Unidirectional Prepreg
1) Flat appearance with uniform thickness; no obvious defects that would interfere with use or operation.
2) Fibers should be continuous without cross deformation, wrinkles, or looseness.
3) Resin should completely impregnate fibers with uniform distribution; no dry yarn areas or resin-rich zones.
4) No foreign matter present.
5) No permanent folds or wrinkles that damage the fibers.
6) Yarn hair groups: Less than 0.02㎡ cumulative area per square meter; no fiber deformation caused.
2. Carbon fiber fabric prepreg
1) Flat appearance with uniform thickness; no obvious defects affecting use or operation.
2) Resin fully impregnates fibers with uniform distribution; no dry yarn areas or resin-rich zones.
3) No foreign contaminants present.
4) No permanent folds or wrinkles that damage the fibers.
5) Fabric has no sparse/dense areas; warp/weft yarns have no obvious deformations or breaks, are perpendicular to each other and parallel in their respective directions.
Appearance is visually inspected using a 1 mm steel ruler.
II. Our company uses standard sizes: each roll is 100m long and 1000mm wide. Measurements are taken with a steel ruler (minimum scale 1mm, length over 1m) and recorded numerically. The deviation in width must not exceed 10 mm.
III. Physical Property Testing (Sampling)
1. Prepreg Density - Unidirectional Carbon Fiber: 90-298g/㎡ (±5% deviation), 336-896g/㎡ (±8% deviation) - Carbon Fiber Fabric: 209-1067g/㎡ (±5% deviation) Inspection follows HB 7736.2 regulations.
2. Fiber density - Unidirectional carbon fiber: 54-200g/㎡ (±5% deviation), 225-600g/㎡ (±8% deviation) - Carbon fiber weave: 125-640g/㎡ (±5% deviation) Inspection according to HB 7736.3 regulations.
3. Volatile Content Volatile content ≤1.5%, tested according to HB 7736.4.
4. Resin content Standard values: 40±3, 38±3, 33±3; test according to HB 7736.5.
5. Gel Time Inspection according to HB 7736.7.
Storage Conditions Prepreg products require low temperature storage: - Room temperature (25℃): 1-month shelf life - -5℃ to 0℃: 3-month shelf life - Below -18℃: 6-month shelf life
Quality control begins with raw materials to produce high-performance carbon fiber composites with high strength, low weight, corrosion resistance and excellent seismic strength.
