Abstract: The technical principle and structural features of J 70 air-jet vortex spinning machine were introduced. The technical path to achieve 600 m/min spinning speed was analyzed focusing on seven core technologies including high-speed spinning unit, individual spindle piecing, super-long nose bar, digital yarn clearer, progressive piecing technology, integral traverse device and independent spindle drive. Taking 36.9 tex viscose yarn as an example, the spinning process and yarn quality of J 70 and MVS870 EX were compared. The results showed that under similar evenness level, the spinning speed of J 70 could reach 580–600 m/min, while exhibiting slightly lower slub and nep counts than the reference machine, and the progressive piecing technology realized traceless piecing. J 70 demonstrates significant advantages in high speed, high yield, piecing quality and flexible production, making it well-suited for diversified blended spinning of multiple varieties.

Key words: air-jet vortex spinning machine; J 70; quality; digitization; piecing technology; adaptability