Quality Inspection Date: December 2, 2025
Applicability: This checklist is applicable for outgoing inspection, warehousing inspection and incoming material inspection of PVC foam boards, covering core inspection items for appearance, internal quality and functional technical parameters. Sensitive information such as customer, supplier and contract details has been redacted in accordance with relevant requirements to protect the interests of all parties.
Scope: Adapted for quality control scenarios in foreign trade inspection and factory production, with clear inspection standards, methods and acceptance criteria.
Part 1: Appearance Inspection Checklist
This checklist covers key inspection positions including board surface, edges and corners, and clarifies the acceptance criteria, inspection methods and non-conformity judgment for appearance quality of PVC foam boards.
| Inspection Item | Inspection Position | Acceptance Criteria (Qualified Requirements) | Inspection Method | Non-Conformity Judgment (Unqualified Cases) |
|---|---|---|---|---|
| Surface Cleanliness | Entire front and back surfaces of the board | No obvious dust, oil stains, glue marks, fingerprints or other foreign matter attached to the surface. | Visual inspection under natural light (or 40W fluorescent lamp) at a distance of 30cm~50cm from the board surface. | Visible oil/glue stains that cannot be wiped off; large-area dust coverage; dense fingerprints affecting appearance. |
| Color Difference | Entire front/back surfaces of a single board; between boards of the same batch | 1. No obvious color gradation or color spots on the surface of a single board;2. Color difference between boards of the same batch and specification ≤ Grade 4 in GB/T 15608-2006. | 1. Single board: Visual inspection of the entire surface, focusing on the center and edge areas;2. Same batch: Place 3 sample boards side by side and conduct visual comparison under natural light. | Obvious color spots or color streaks on a single board; color difference between boards of the same batch exceeding Grade 4 with easily distinguishable naked-eye differences. |
| Surface Defects (Dents/Bulges) | Entire front and back surfaces of the board | 1. Dents: Diameter ≤ 0.5mm, ≤ 3 dents per square meter (not concentrated); no dents with depth ＞ 0.2mm;2. Bulges: No bulges (including air bubble protrusions) are allowed. | Visual inspection + hand touch; measure the diameter/depth of suspected defects with a caliper. | Dents with diameter ＞ 0.5mm or depth ＞ 0.2mm; ≥ 1 bulge; defects concentrated in prominent positions on the board surface. |
| Surface Scratches | Entire front and back surfaces of the board | 1. Shallow scratches: Length ≤ 5cm, width ≤ 0.1mm, ≤ 2 scratches per square meter (without affecting visual flatness);2. Deep scratches: Not allowed (base material visible, obvious groove felt by hand). | 1. Visual inspection of the entire surface, oblique observation of reflective areas;2. Hand touch of suspected scratch positions;3. Measure scratch width/depth with a caliper. | ≥ 1 deep scratch; shallow scratches with length ＞ 5cm or ＞ 2 scratches per square meter; obvious damage caused by crossed scratches. |
| Surface Peeling/Delamination | Entire front/back surfaces; interlayer bonding areas | No surface peeling, delamination or degumming is allowed. | Visual inspection + hand tear test (gently tear the edge area, no delamination). | Surface peeling or edge warping; interlayer separation or degumming that can be torn apart by hand. |
| Board Surface Flatness | Entire board surface | 1. Length ≤ 2m: Warpage ≤ 0.5%;2. Length ＞ 2m: Warpage ≤ 0.3%;3. No waviness or bending deformation. | 1. Place the board on a horizontal platform and visually check the fit between the edge and the platform;2. Attach a steel straightedge (length ≥ 1m) to the board surface, measure the maximum gap value, and calculate warpage (Warpage = Gap value / Measurement length × 100%). | Warpage exceeding the corresponding standard; obvious waviness or bending of the board surface with gap ＞ 3mm after attaching the steel straightedge. |
| Edge Quality | Four peripheral edges of the board | 1. Clean and flat cutting edges, no burrs, chipping or corner missing;2. Edge straightness: Deviation ≤ 0.5mm per meter;3. No obvious serration or cracks. | 1. Visual inspection of the entire edge;2. Attach a steel straightedge to the edge and measure the straightness deviation;3. Hand touch of the edge to check for burrs/chipping. | Obvious burrs or chipping on edges (material loss ＞ 1mm); edge straightness deviation ＞ 0.5mm per meter; cracks or serrated damage on edges. |
| Corner Quality | Four corners of the board | 1. Right angles (90°±0.5°);2. No corner missing, chipping or excessively large rounded corners;3. No cracks at corners. | 1. Measure corner angles with a try square;2. Visual + hand touch inspection of corner integrity. | Corner angle deviation ＞ 0.5°; corner missing/chipping with size ＞ 2mm; cracks at corners. |
| Printing/Laminating Quality (if applicable) | Printing/laminating areas on the board | 1. Printing: Clear patterns, no double images, missing printing or fading, overprint deviation ≤ 0.2mm;2. Laminating: Tight fit of the film layer, no wrinkling or air bubbles, no edge warping. | 1. Visual inspection of the integrity of printing/laminating areas;2. Lightly stick adhesive tape on the laminated surface and check for no film peeling after tearing;3. Measure overprint deviation with a caliper. | Blurred, missing or faded printing patterns; ≥ 3 wrinkles/air bubbles on the laminated layer; overprint deviation ＞ 0.2mm; laminated edge warping ＞ 1cm. |
| Marking Completeness (if applicable) | Designated position on the board surface | Markings (brand, specification, batch number, grade) are clear, complete, legible and in compliance with position requirements. | Visual inspection of the content and position of markings. | Missing or illegible markings; marking position deviated from the designated area by ＞ 2cm. |
Part 2: Internal Quality Inspection Checklist
This checklist focuses on the internal physical and chemical properties of PVC foam boards, with inspection standards and methods in line with industry common specifications for foreign trade quality control.
| Inspection Item | Inspection Basis/Standard | Acceptance Criteria (Qualified Requirements) | Inspection Method | Non-Conformity Judgment (Unqualified Cases) |
|---|---|---|---|---|
| Density | GB/T 1033.1-2008 | Density deviation of the same batch of boards ≤ ±5% of the nominal value (nominal density to be confirmed according to product specifications). | Cut samples (100mm×100mm) from the middle of the board, remove surface impurities, measure the mass with an electronic balance (accuracy: 0.01g) and dimensions with a caliper, then calculate density (Density = Mass / Volume). | Density deviation exceeding ±5% of the nominal value; uneven density distribution in the sample with obvious internal voids. |
| Water Absorption | GB/T 1034-2008 (Method A: Immersion) | Water absorption ≤ 0.3% after immersion in distilled water at 23℃±2℃ for 24 hours. | Cut samples (50mm×50mm), dry to constant weight (m1) in an oven at 60℃±2℃, immerse in distilled water for 24 hours, take out, wipe off surface water with filter paper and weigh (m2), calculate water absorption (Water absorption = (m2-m1)/m1 × 100%). | Water absorption ＞ 0.3%; obvious water seepage or swelling of the sample after immersion. |
| Interlayer Bonding Strength | GB/T 1453-2005 | Interlayer bonding strength ≥ 0.8MPa; no delamination or separation at the bonding interface after the test. | Conduct a tensile shear test on the sample (100mm×25mm) with a universal testing machine at a tensile speed of 50mm/min; record the maximum shear force and calculate bonding strength (Bonding strength = Maximum shear force / Bonding area). | Interlayer bonding strength ＜ 0.8MPa; delamination, separation or adhesive failure at the bonding interface during the test. |
| Impact Resistance (Izod) | GB/T 1043.1-2008 (Notched) | Notched impact strength ≥ 2.0 kJ/m² (for boards with thickness ≥ 3mm). | Process notched samples (80mm×10mm×thickness) according to the standard, conduct the Izod impact test with an impact testing machine at room temperature, and record the impact strength value. | Notched impact strength ＜ 2.0 kJ/m²; brittle fracture of the sample with obvious cracks extending to the non-notched area. |
| Heat Resistance | GB/T 1633-2000 (Vicat Softening Temperature) | Vicat softening temperature ≥ 70℃ (for general-purpose PVC foam boards). | Test the sample (10mm×10mm×thickness) with a Vicat softening temperature tester at a heating rate of 50℃/h and a test load of 10N; record the temperature when the indenter penetrates 1mm into the sample. | Vicat softening temperature ＜ 70℃; severe deformation, melting or penetration depth exceeding 1mm at a temperature below 70℃. |
| Internal Void Content | Industry common specification | Internal closed void content ≥ 85%; no large open voids (diameter ＞ 2mm) or continuous void channels inside the board. | Observe the cross-section of the sample (50mm×50mm) under a stereomicroscope (magnification: 10×); calculate the void content by image analysis software and check for open voids/void channels. | Closed void content ＜ 85%; presence of large open voids (diameter ＞ 2mm) or continuous void channels inside the board; loose internal structure with obvious powdering. |
Part 3: Functional & Technical Parameter Test Checklist
This checklist verifies the key functional performance and technical parameters of PVC foam boards to ensure compliance with the application requirements of foreign trade customers.
| Inspection Item | Inspection Position/Object | Acceptance Criteria (Qualified Requirements) | Inspection Method | Non-Conformity Judgment (Unqualified Cases) |
|---|---|---|---|---|
| Dimensional Deviation | Entire board (length, width, thickness) | 1. Length/width deviation: ≤ ±0.2% of the nominal size (maximum deviation ≤ ±5mm);2. Thickness deviation: ≤ ±0.1mm for thickness ≤ 5mm, ≤ ±2% of the nominal thickness for thickness ＞ 5mm. | 1. Measure length/width at 3 points (two ends and middle) with a steel tape (accuracy: 1mm) or steel ruler (length ≥ 2m);2. Measure thickness at 9 points (uniformly distributed) with a micrometer (accuracy: 0.01mm); calculate the average value and deviation. | Length/width deviation exceeding ±0.2% (or ±5mm); thickness deviation exceeding the corresponding standard; uneven dimensional distribution with obvious size differences at different positions. |
| Thickness Uniformity | Entire board surface | Thickness variation coefficient (CV) ≤ 3% (calculated based on 9-point thickness measurement data). | Calculate the thickness variation coefficient (CV = Standard deviation / Average thickness × 100%) using the 9-point thickness measurement data from the dimensional deviation test. | Thickness variation coefficient (CV) ＞ 3%; obvious thickness difference between the center and edge of the board with hand-touchable unevenness. |
| Flame Retardancy (if required) | Entire board sample | Meet the requirements of GB 8624-2012 Grade B1 (combustion performance for building materials) or customer-specified flame retardant grade. | Conduct the vertical burning test or oxygen index test on the sample (100mm×10mm×thickness) according to GB 8624-2012; measure the oxygen index with an oxygen index tester (oxygen index ≥ 32% for Grade B1). | Failing to meet the specified flame retardant grade; severe burning with dripping and spreading during the vertical burning test; oxygen index ＜ 32% (for Grade B1 requirement). |
| Chemical Resistance | Board surface (front/back) | No obvious discoloration, swelling, blistering or dissolution after contact with common chemicals (e.g., 5% NaCl solution, 10% ethanol) at 23℃±2℃ for 24 hours. | Apply the test chemical to the board surface (10cm×10cm area) with a dropper, cover with a watch glass, remove after 24 hours, wipe off the chemical and conduct visual + hand touch inspection of the surface. | Obvious discoloration, swelling, blistering, dissolution or softening of the board surface after chemical contact; irreversible damage to the surface with reduced hardness. |
| Weather Resistance (accelerated) | Board surface (front/back) (if required) | No obvious color fading (fading grade ≥ 4), chalking or cracking after 500 hours of UV aging test (GB/T 16422.3-2014). | Conduct the accelerated UV aging test on the sample according to GB/T 16422.3-2014 (UV intensity: 0.71W/m², temperature: 60℃±3℃); evaluate the fading grade with a gray scale and check for chalking/cracking. | Fading grade ＜ 4 after UV aging test; obvious chalking (chalking grade ≤ 2) or cracking on the board surface; severe surface degradation with peeling. |
| Load-Bearing Capacity | Entire board (if applicable for structural use) | No permanent deformation (deformation rate ≤ 2%) after bearing a static load of 500N/m² at 23℃±2℃ for 24 hours; no fracture or damage when the load is removed. | Place the board on two supports (span: 1m), apply a uniform static load (500N/m²) on the surface with a weight, remove the load after 24 hours and measure the deformation value; calculate the deformation rate (Deformation rate = Deformation value / Span × 100%). | Permanent deformation rate ＞ 2% after load removal; fracture, cracking or structural damage of the board during the load-bearing test; obvious sagging with reduced load-bearing capacity. |
Supplementary Inspection Instructions
- Inspection Environment: It is recommended to conduct the inspection in an environment with temperature 23℃±5℃ and relative humidity 50%±10%. Avoid direct strong light or dim environment to prevent affecting the judgment accuracy. For precision tests (e.g., density, impact resistance), the environmental conditions shall comply with the corresponding national standard requirements.
- Sampling Rules: Incoming material/outgoing inspection shall be implemented in accordance with GB/T 2828.1-2012, adopting the normal inspection single sampling plan with AQL (Acceptable Quality Level) = 2.5 for major defects (MA) and AQL = 4.0 for minor defects (MI). Severe defects (CR) are not allowed (acceptance number = 0).
- Defect Classification: Defects are classified into three levels in accordance with foreign trade quality control norms and customer requirements:
- Critical Defects (CR): Defects that affect the safety, performance and basic use of the product, or cause serious losses to customers (e.g., delamination, severe chemical corrosion, failure to meet flame retardancy requirements).
- Major Defects (MA): Defects that affect the appearance, assembly and normal use of the product, but do not involve safety issues (e.g., deep scratches, excessive warpage, unqualified interlayer bonding strength).
- Minor Defects (MI): Defects that have little impact on the product performance and use, and can be corrected without affecting the customer’s acceptance (e.g., a small number of shallow scratches, slight handprints, minor marking position deviation).
- Inspection Record & Disposal: All inspection results shall be recorded in detail in the quality inspection report, including the inspection item, test value, judgment result and defect description (with photos if necessary). For non-conforming products, corresponding disposal measures (e.g., rework, rejection, sorting) shall be taken in accordance with the factory’s quality control procedures and customer requirements.
- Sample Retention: Retain the qualified/unqualified samples for at least 3 months after inspection for re-inspection or customer confirmation if necessary. The sample retention conditions shall be consistent with the product storage requirements (dry, ventilated, away from direct sunlight and corrosive substances).
