Custom Single Closed Loop Extension Spring Music Wire SWP-B Blue Zinc Plated

This single closed loop extension spring is a precision custom wire forming spring fabricated from premium SWP-B music wire, also named blue zinc plated pull spring for mechanical reset applications. Our factory adopts CNC spring coiling machine to integrally wind the spiral body and form one closed hanging loop in one molding process, eliminating assembly gaps. After stress relief tempering, trimming, deburring, degreasing cleaning and blue zinc electroplating anti-corrosion treatment, every music wire extension spring gets uniform dimensional accuracy and stable tensile force. As a reliable mechanical reset extension spring, it can be fully customized via our OEM custom service, with adjustable wire diameter, coil count, overall length, loop shape and surface coating to match diverse industrial equipment load requirements. As a professional custom spring manufacturer, we accept drawing & sample customization for all types of extension springs.

• Light industrial mechanical equipment
• Office automation devices
• Household appliance hardware
• Fitness equipment accessories
• Automated conveyor machinery
• Electronic cabinet reset components
• Textile machinery parts
• Small automation actuator reset structures
• General hardware reset assemblies

As a professional custom wire forming spring manufacturer, we provide full OEM custom service for single closed loop extension spring & music wire extension spring:

1. Custom wire diameter, coil count, free length, outer diameter and loop shape per customer drawings or samples
2. Custom surface treatment: blue zinc plating, nickel plating, black oxide, passivation etc.
3. Custom load force, tensile strength and elastic coefficient for mechanical reset needs
4. Custom packaging, marking and batch production to meet bulk order demands
5. One-stop solution: design optimization, prototype trial, mass production, full quality inspection

1. Stable elasticity after tempering treatment: Solve customer spring loose force & deformation after long-term reciprocating reset use
2. Precision CNC integrated forming with ±0.03mm tolerance: Avoid inconsistent loop size leading to assembly jamming & installation mismatch
3. Blue zinc plated anti-corrosion layer: Resist workshop humidity & chemical splash, extend service life, cut frequent replacement cost
4. Full deburring & smooth hanging loop: Prevent scratch on matching mounting parts during assembly
5. Full pre-delivery tensile & salt spray testing: Eliminate defective goods risk, avoid on-site equipment failure caused by unqualified pull spring
6. Flexible OEM custom service: No need for customers to compromise equipment design due to fixed standard spring sizes

1. Raw material incoming inspection: Verify SWP-B music wire hardness & tensile property
2. In-process dimensional sampling inspection after CNC coiling & shaping
3. 100% deburring & visual check to remove sharp metal edges
4. Post-plating thickness & uniformity inspection for blue zinc plated pull spring
5. Finished product tensile load test to confirm mechanical reset performance
6. Salt spray corrosion resistance test to validate surface anti-rust effect
7. Final full dimensional & appearance inspection before warehouse delivery

1. Can you make custom single closed loop extension spring with different sizes?

Yes, we support full OEM custom service, accept customer drawings & samples to adjust wire diameter, coil count, length and loop design.

2. What’s the lead time for custom music wire extension spring orders?

Prototype samples take 3-5 working days, mass bulk orders take 7-15 working days based on quantity.

3. Is blue zinc plating the only surface finish for this pull spring?

No, we offer multiple custom surface treatments including nickel plating, zinc passivation as per your working environment.

4. What tolerance can you guarantee for custom wire forming spring dimensions?

Our standard precision tolerance is ±0.03mm for key dimensions, tighter tolerance can be customized for high-precision machinery.

5. Do you provide test reports for mechanical reset extension spring?

Yes, we can supply tensile test, salt spray test and dimensional inspection reports upon customer request.