PP Screws in Food Processing Equipment - Acid/Heat Resistant, FDA Compliant | FASTKING Case
Case Background
A East-China dairy plant operates 6 Tetra Pak brick filling lines. The pipe flanges were originally fastened with SUS316L stainless steel wing nuts (for daily 80°C acidic CIP manual disassembly). Two issues emerged: 1) 316L wing nuts leached metal ions into milk protein, with Fe/Cr/Ni residues exceeding GB 4806.9 limits; 2) the complex wing-nut geometry made stainless machining cost ¥18/piece, with annual consumption of 8,000 pieces reaching ¥144k per line just for nuts.
Solution
FASTKING recommended PP (polypropylene) food-grade natural wing nuts. PP meets FDA 21 CFR 177.1520 + EU 10/2011 + GB 4806.7 food contact regulations. With density 0.91 g/cm³ (lightest engineering plastic) and water absorption < 0.02%, PP eliminates metal-ion leaching. Wing geometry is single-shot injection molded, reducing unit cost to ¥1.8.
Specifications
- Material: PP natural, food-grade (FDA 21 CFR 177.1520 + EU 10/2011)
- Sizes: M6×20 / M8×25 / M10×30 wing nuts with PP flat washers
- Performance: continuous 100°C (short-term 120°C), water absorption < 0.02%, density 0.91 g/cm³
- Chemical resistance: 5% nitric, 3% sodium hydroxide, lactic, citric acids (typical CIP chemicals)
Results
Over 18 months, FASTKING delivered 58,000 PP wing nuts across 6 filling lines:
- Zero metal-ion leaching; Fe/Cr/Ni in milk all below GB 4806.9 food-contact limits.
- Annual cost per line ¥14.4k × 6 lines = ¥86k vs original ¥864k — saving ¥125k annually (or ¥17k/line).
- 30% faster manual disassembly due to lighter PP wing nuts (operator feedback).
- Helped customer pass ISO 22000 / FSSC 22000 food safety audits.
- All 14 filling lines now standardized on PP wing nuts.
Contact FASTKING for food-grade or pharma-grade fastener selection (PP / PE / pvdf / peek) or FDA documentation.