The resin lead core has strict inspection standard:
1. Lead core should be straight, round, smooth, without elbow, fracture, cut surface and so on.
2. The length and diameter shall be unified without obvious errors. Diameter error: 0.5mm+0.08+0.05,0.7mm+ 0.03-0.01; Length error: plus or minus 1 mm.
3. Lead core materials should be made of resin graphite lead core.
4, the abrasion coefficient of the lead should be 0.16 mm or less 0.5 mm / 2 b/m, 0.7 mm / 2 b should be 0.12 mm/m or less 5, lead the flexural strength, of the 0.5 mm / 2 b should be 150 million or more, of the 0.7 mm / 2 b should be 140 million or 6, the packing should be packed in wooden case or other fastening devices, and carton apparent position should put a "fragile", "handle with care", etc. The volunteers to ensure a complete qualified product to our company.
7. The remaining items should meet the requirements of QB/t1024-2007.