Overview
Plastic coil nails are widely used in construction, packaging, and woodworking industries due to their high efficiency and strong fixing performance. The quality of plastic coil nails directly affects the safety and durability of the applied products. Therefore, strict quality testing is essential before leaving the factory. This article details the key test items, methods, and standards for plastic coil nails, providing a comprehensive reference for quality inspection
Key Test Items and Methods
1. Appearance Inspection
- Test Tools: Visual inspection, 10x magnifying glass.
- Test Methods: Randomly select 50 plastic coil nails from the batch. Check the surface of the nail body and plastic coil for defects such as cracks, burrs, rust, deformation, and uneven coating. Use a magnifying glass to observe whether the plastic coil is firmly bonded to the nail body without loosening or peeling. Ensure the nail head is intact without missing corners or deformation.
- Acceptance Standard: The qualified rate of appearance shall not be less than 98%. No critical defects such as cracks or rust are allowed.
2. Dimensional Accuracy Test
- Test Tools: Vernier caliper (precision 0.01mm), tape measure, gauge.
- Test Methods: Measure the key dimensions of 30 samples, including nail length (tolerance ±0.3mm), nail diameter (tolerance ±0.05mm), nail head diameter and thickness, and the inner diameter and width of the plastic coil. Check whether the pitch between adjacent nails is uniform, with a tolerance of ±0.5mm.
- Acceptance Standard: All measured dimensions shall comply with the specified product drawings or national standards (such as ISO 10653 for international standards, GB/T 12618 for Chinese standards).
3. Mechanical Performance Test
- Tensile Strength Test：
- Test Equipment: Universal testing machine.
- Test Methods: Clamp the nail body and plastic coil of the sample on the testing machine, apply axial tension at a speed of 5mm/min until the nail body breaks or the plastic coil detaches. Record the maximum tensile force.
- Acceptance Standard: The tensile strength of the nail body shall not be less than 600MPa, and the bonding strength between the plastic coil and the nail body shall not be less than 50N.
- Shear Strength Test：
- Test Equipment: Shear testing fixture, universal testing machine.
- Test Methods: Fix the nail body in the shear fixture, align the shear plane with the nail head root, apply shear force at a speed of 3mm/min, and record the shear failure load.
- Acceptance Standard: The shear strength shall not be less than 450MPa.
4. Corrosion Resistance Test
- Test Method: Neutral salt spray test (in accordance with ASTM B117 standard).
- Test Process: Place 10 samples in a salt spray test chamber with a 5% NaCl solution, temperature (35±2)℃, and continuous spray for 48 hours. After the test, take out the samples, rinse with clean water, dry, and observe the surface corrosion.
- Acceptance Standard: No obvious rust or corrosion spots on the nail body, and the plastic coil shall not crack or peel due to corrosion.
5. Coil Flexibility Test
- Test Tools: Bending tester, torque wrench.
- Test Methods: Wind the plastic coil nail around a mandrel with a diameter 3 times the inner diameter of the coil, bend back and forth 5 times, and check whether the plastic coil is cracked or the nail body is deformed. Use a torque wrench to test the rotational flexibility of the coil, ensuring smooth unwinding during use.
- Acceptance Standard: No cracks, breaks, or deformation after bending; the coil unwinds smoothly without jamming.
Test Sampling and Judgment Rules
- Sampling Method: Adopt random sampling from the same batch of products. For batches of less than 10,000 pieces, sample 50 pieces; for batches of 10,000-50,000 pieces, sample 100 pieces; for batches exceeding 50,000 pieces, sample 150 pieces.
- Judgment Rules: If the unqualified rate of a single test item is less than 5%, the batch is qualified; if the unqualified rate is 5%-10%, double sampling inspection is required; if the unqualified rate of the re-inspected sample exceeds 5%, the batch is unqualified. Critical defects such as cracks and insufficient mechanical strength directly determine the batch as unqualified.
Conclusion
The quality test of plastic coil nails covers multiple dimensions such as appearance, size, mechanics, and corrosion resistance. Strict adherence to the above test methods and standards can effectively ensure the product quality and avoid potential safety hazards in application. Enterprises should establish a complete quality inspection system, conduct full-process monitoring from raw materials to finished products, and continuously improve the reliability and stability of plastic coil nails.
Post time: Dec-26-2025