IMPROVING SILK REELING EQUIPMENT TO OBTAIN HIGH-QUALITY RAW SILK FROM LOCAL SILKWORM COCOONS

The quality of raw silk is determined jointly by the intrinsic properties of the cocoon and by the mechanical and thermal environment in which the filament is unwound. Local cocoon hybrids frequently show high intrinsic potential, yet raw silk reeled on ageing, mostly mechanically controlled equipment is often downgraded because of fineness variation, frequent filament breakage and elevated cleanness defects. This study presents the design, implementation and experimental evaluation of an integrated set of seven equipment improvements: cocoon sorting, staged three-zone cooking, closed-loop reeling-basin temperature control, ceramic eyelets with an optimized cross-twist unit, a photoelectric fineness sensor with automatic cocoon feeding, a load-cell based adaptive take-up, and humidity-controlled drying. The modifications were driven by a PLC-based PID controller with data logging. The structural and kinematic schemes of the improved reeling unit are presented, and its reel drive, consisting of an asynchronous motor with a frequency converter, a V-belt drive and a two-stage cylindrical gear reducer, is calculated so that the reeling speed can be set within 36-84 m/min. Five lots of locally produced cocoons were reeled to 20/22 den raw silk on a baseline machine and on the improved machine, with three replicates per lot. The improved configuration raised reelability from 71.2 % to 86.4 %, increased raw silk recovery from 34.9 % to 39.6 %, reduced the coefficient of variation of fineness from 14.2 % to 7.8 %, lowered the filament break rate by 58 %, and improved tenacity by 14.3 %, moving the product from an intermediate grade to the top commercial grade. Specific thermal energy consumption decreased by 29 %. The results show that targeted, low-cost equipment upgrades can unlock the quality potential of local cocoons without changing the raw material, and they provide design rules that can be transferred to small and medium reeling enterprises.