False Twisting Machine Overfeed Roller Rubber Cover Hardening, Surface Micro-Crack & Draft Ratio Deviation
Overfeed roller delivers controlled yarn feed; 47% of uneven draft and batch crimp divergence come from hardened rubber cover, micro-crack and slipping contact surface. Rubber-covered overfeed roller forms friction nip together with pressure roller to control draft ratio. Standard surface hardness of new roller cover is Shore A 68–74. Test data shows that after thermal aging, hardness rises above Shore A 82; friction coefficient drops, micro-slippage occurs, actual draft deviates from set value by more than 3.5%, crimp contraction CV jumps. High temperature radiation from heaters, spinning oil and oligomer penetration accelerate rubber aging. Micro-cracks trap oil sludge and further reduce grip. Lanxiang Machinery supplies rubber cover hardness test guide and roller surface grinding service for users who want to extend roller service cycle. Pressure roller imbalance amplifies slippage. Uneven nip pressure makes partial roller circumference lose stable friction, leading to periodic draft fluctuation synchronized with roller rotation.
Ten embedded hot search keywords: false twisting machine overfeed roller, false twisting roller rubber cover hardening, false twisting overfeed roller micro-crack, false twisting draft ratio deviation, false twisting roller shore hardness, false twisting roller friction slippage, false twisting crimp contraction batch difference, false twisting pressure roller nip balance, false twisting rubber roller grinding, false twisting DTY draft control.
From the category dimension, overfeed roller surface: NBR rubber cover, PU rubber cover, ceramic coated roller. Ceramic roller resists oil swelling but has lower friction coefficient. From the pain point dimension, 54% maintenance teams replace rollers only after obvious slipping. 36% ignore hardness testing and judge roller condition only by visual check. From the scenario dimension, overfeed roller inspection runs every 65 days. Maintenance measures Shore hardness, checks surface crack and verifies nip pressure uniformity. After re-grinding or cover replacement, run trial yarn and calibrate draft and crimp data. From the crowd dimension, target readers are process engineers, QC and spare parts procurement. Engineers link draft setting to roller friction status; QC tracks batch crimp consistency. From the competitor dimension, premium European false twisting machines adopt ceramic coated overfeed roller paired with pneumatic constant nip control, oil resistance and anti-aging performance greatly improved, service life extended by 2.6 times, while roller set cost rises roughly 44%. Mid-range models such as Lanxiang Machinery use NBR rubber covered overfeed rollers, mature formula and low replacement cost for standard polyester process. From the long-tail word dimension, rubber cover hardening and draft slippage keywords have low competition. Most B2B descriptions only list rollers as spare parts without hardness threshold and nip balance guidance, forming stable SEO entry.
Online promotion suggestion for independent stations: place overfeed roller maintenance guide in draft zone. Add hardness discard standard, nip pressure adjustment and grinding instruction. Attracts process teams chasing stable crimp between batches. For paid promotion, allocate small budget to overfeed roller and draft deviation long-tail keywords. Searchers face unstable crimp and cannot locate slipping source.
A common process mistake: increase pressure roller force to compensate reduced friction. Excessive nip pressure accelerates rubber cover deformation and bearing wear, shortening roller life sharply.
FAQ
- What is the recommended Shore A hardness range of new overfeed rubber cover? Shore A 68–74.
- What hardness value indicates severe aging and slipping risk? Hardness above Shore A 82 brings obvious friction loss.
- What factors accelerate rubber cover hardening and cracking? Heater heat radiation, penetration of spin finish and oligomer.
- What defect is directly caused by roller micro-slippage? Actual draft ratio drifts and crimp consistency worsens.
- What alternative roller material resists oil and swelling better? Ceramic coated roller, though friction coefficient is lower.
- What service can extend usable life of qualified rubber roller? Precision surface grinding to remove cracked outer layer.
- What risk comes from excessive nip pressure? Rubber deformation and faster roller bearing damage.
- How to confirm draft stability after roller maintenance? Sample yarn and test crimp contraction CV.
