From Technical Drawings to Quality Die Springs: Inside Cixi Dingli Spring Co., Ltd’s Traditional Manufacturing Excellence

Introduction: 30 Years of Reliable Spring Manufacturing

In the world of spring manufacturing, there’s no substitute for experience and proven processes. Since 1995, Cixi Dingli Spring Co., Ltd has been quietly but consistently producing quality springs for industries across China and beyond. We’re not the flashiest manufacturer with the latest buzzwords, but what we offer is something more valuable: reliable quality, honest service, and springs that simply work.

With 20,000 square meters of production space, over 70 million RMB in total investment (including 20 million RMB in equipment), we’ve built a solid foundation for traditional spring manufacturing. Our 30+ technical staff members, each with over 15 years in the die spring industry, represent real expertise – not marketing promises, but hands-on knowledge gained from producing millions of springs.

Understanding Our Core Materials: The Foundation of Quality

Practical Material Selection for Real Applications

At Dingli Spring, we work with five primary materials that cover 95% of industrial spring applications:

65Mn Carbon Steel

• Our workhorse material for general die springs
• Cost-effective without compromising quality
• Hardness after treatment: 45-48 HRC
• Best for standard load applications

50CrVA Chrome Vanadium Steel

• Enhanced durability for demanding applications
• Better performance at elevated temperatures (up to 250°C)
• Popular for heavy-duty industrial machinery
• Approximately 20% higher cost than 65Mn, but 40% longer service life

55CrSi Chrome Silicon Steel

• Superior fatigue resistance
• Excellent for high-cycle applications
• Maintains properties under repeated stress
• Common in precision tooling applications

Music Wire (Piano Wire)

• Highest tensile strength in our range
• Ideal for small precision springs
• Consistent quality for electronic applications
• Limited to smaller wire diameters (typically under 6mm)

304 Stainless Steel

• Corrosion resistance for special environments
• Food processing and medical equipment applications
• Lower spring rates compared to carbon steel
• Higher material cost but essential for specific uses

Our Manufacturing Process: Traditional Methods, Consistent Results

For a detailed visual overview of our complete production process, visit our spring winding process page.

Step 1: Drawing Review and Planning

When your technical drawings arrive, our engineering team doesn’t use fancy AI systems – they use experience. Each drawing is reviewed by senior technicians who ask practical questions:

• Is the design manufacturable with our equipment?
• Are the tolerances realistic for the application?
• Can we suggest cost-saving modifications without affecting performance?

We provide feedback within 24-48 hours, often suggesting minor adjustments that can reduce costs by 15-20% while maintaining functionality. For custom spring solutions, our engineering team works closely with you to optimize designs for your specific application.

Step 2: Material Preparation

Our material inventory is one of our genuine advantages. With several hundred tons of steel wire in stock, we can start most orders immediately. Each material batch comes with:

• Mill certificates showing chemical composition
• Basic mechanical property data
• Our incoming inspection records

We don’t claim perfect traceability to individual springs, but we maintain batch records that link finished products to material sources.

Step 3: CNC Spring Coiling

Our coiling department features both newer CNC machines and reliable mechanical coilers that have been producing quality springs for over a decade. The spring winding process includes:

CNC Machines (for complex or precision work):

• Wire diameter capacity: 0.5mm to 16mm
• Programmable for variable pitch designs
• Production rate: 50-150 pieces/hour depending on complexity
• Best for custom designs and tight tolerances

Mechanical Coilers (for standard products):

• Wire diameter capacity: 1mm to 20mm
• Consistent quality for high-volume production
• Production rate: 100-300 pieces/hour
• Cost-effective for standard specifications

Step 4: Heat Treatment

Heat treatment is where good springs become reliable springs. Our process is straightforward but effective:

1. Stress Relief (for all springs):
   • Temperature: 250-350°C
   • Duration: 30-45 minutes
   • Eliminates internal stresses from coiling
2. Quenching and Tempering (for specified materials):
   • Heating: 820-860°C
   • Oil quenching for rapid cooling
   • Tempering: 420-480°C
   • Results in optimal hardness and toughness

We don’t have the most advanced furnaces, but our experienced operators know how to achieve consistent results with the equipment we have. Learn more about our heat treatment and other after-treatment processes.

Step 5: End Grinding

Flat, perpendicular ends are crucial for die spring performance. Our grinding process ensures:

• End perpendicularity within 1.5°
• Surface flatness within 0.03mm
• Clean, burr-free finish

We use semi-automatic grinding machines that require operator skill but produce excellent results when properly operated.

Step 6: Stress Relieving

This critical step is often overlooked by cheaper manufacturers. We compress each spring type to solid height multiple times to:

• Eliminate initial settling
• Stabilize free length
• Identify any material defects

It’s a simple process but makes a significant difference in spring consistency.

Step 7: Surface Treatment

We offer practical surface treatments based on real needs. Our complete range of surface treatment options includes:

Powder Coating:

• Standard colors for load identification
• Basic corrosion protection
• Applied thickness: 40-60 microns

Oil Coating:

• Temporary rust prevention
• Standard for most carbon steel springs
• Simple but effective

Zinc Plating (outsourced):

• When specified for corrosion resistance
• Adds 3-5 days to delivery time
• Additional cost but sometimes necessary

Step 8: Quality Control

Our quality control is thorough without being excessive:

Load Testing:

• Sampling based on batch size (typically 5-10%)
• Key measurements at specified heights
• Records maintained for one year

Dimensional Checking:

• Free length (100% for small batches, sampling for large orders)
• Diameter verification
• Coil count confirmation

Documentation:

• Test reports with actual measured values
• Material certificates (when requested)
• Batch identification for traceability

We’re honest about what we can and cannot provide. If you need extensive documentation or individual spring certification, we can accommodate this with advance notice and additional fees.

Real Applications: Where Our Springs Work

Plastic Injection Molding Industry

Typical Application: Mold return springs and ejector springs

A plastic products manufacturer in Ningbo uses our springs in injection molds producing household items. Their requirements:

• Consistent free length (±1mm tolerance)
• 500,000 cycle minimum life
• Quick delivery for maintenance replacements

Our solution:

• 50CrVA material for durability
• Standard dimensions from our stock program
• 24-hour delivery for stock items

Result: They’ve been ordering the same specifications for 8 years with minimal issues.

Mechanical Press Industry

Typical Application: Cushion springs and stripper springs

Several stamping factories use our heavy-duty die springs in their mechanical presses:

• High loads (up to 2000kg per spring)
• Compact solid height requirements
• Color coding for different load ratings

Our approach:

• 55CrSi for maximum load capacity
• Powder coating in standard colors
• Maintained inventory for common sizes

Result: Average reorder cycle of 3-6 months with consistent quality.

Electronics Manufacturing

Typical Application: Small precision springs for assembly equipment

Electronics assemblers require small springs for pick-and-place machines and testing fixtures:

• Wire diameter 0.5-3mm
• Precise load requirements
• Stainless steel for cleanroom compatibility

Our solution:

• Music wire or 304 stainless steel
• Tighter tolerance control (±3% on loads)
• Clean packaging for sensitive environments

Result: Stable supply relationship with predictable quality.

For more specialized applications, explore our custom spring solutions designed for specific industry needs.

Our Actual Innovation Plans: Practical Improvements

Investment in New Equipment

We’re not chasing digital transformation or Industry 4.0 buzzwords. Our innovation focus is practical:

New Testing Equipment (Planned for 2026):

• Modern load testing machine with digital readout
• Capability to test up to 5000kg loads
• Faster testing means better sampling rates
• Expected to reduce testing time by 50%

Additional CNC Coiler (Under consideration):

• Increase capacity for complex springs
• Reduce lead times for custom orders
• Better consistency for precision requirements

Automated Packaging Line (In development):

• Semi-automatic counting and boxing system
• Reduce packaging errors
• Faster order fulfillment
• Expected implementation: Q3 2026

These aren’t revolutionary changes, but they represent real improvements in our ability to serve customers efficiently.

Honest Pricing and Lead Times

What to Really Expect

Pricing Factors:

• Material costs (fluctuate with market)
• Order quantity (significant breaks at 1000, 5000, 10000 pieces)
• Complexity (standard designs cost 30-40% less than custom)
• Surface treatment requirements
• Packaging specifications

Realistic Lead Times:

• Stock items: 24-48 hours
• Standard designs, custom dimensions: 5-7 days
• Full custom designs: 10-15 days
• Large orders (>50,000 pieces): 15-25 days
• Surface treatment adds 3-5 days

Minimum Order Quantities:

• Stock items: 100 pieces
• Standard designs: 500 pieces
• Custom designs: 1000 pieces (negotiable)

Working with Dingli Spring: A Straightforward Process

Simple Steps, Clear Communication

1. Send Your Requirements
   • Technical drawings (any format)
   • Or sample springs
   • Or even basic sketches with dimensions
2. Technical Review (1-2 days)
   • Feasibility assessment
   • Cost optimization suggestions
   • Material recommendations
3. Quotation (Same day for standard, 1-2 days for custom)
   • Clear pricing breakdown
   • Lead time confirmation
   • Payment terms (typically 30% deposit)
4. Sample Production (Optional)
   • Usually 5-10 pieces
   • 5-7 days for production
   • Sample fees deducted from production orders
5. Mass Production
   • Regular updates on progress
   • Photos before shipping (if requested)
   • Flexible packaging options
6. Shipping
   • Domestic: Various logistics partners
   • Export: FOB Ningbo or Shanghai typically
   • We can arrange shipping or use your forwarder

Common Issues and Honest Solutions

Problems We’ve Seen and Solved

Issue: Springs taking a set (losing free length)
Solution: Proper stress relieving and material selection. Sometimes spending 10% more on better material saves 50% in replacements.

Issue: Inconsistent loads in production batches
Solution: Tighter process control and increased sampling. We can provide enhanced QC for critical applications.

Issue: Rust during storage
Solution: Proper packaging with VCI paper or oil coating. Simple solutions that work.

Issue: Delivery delays
Solution: Our large inventory helps, but we also recommend customers maintain safety stock for critical items.

Quality Certifications: What We Actually Have

We hold two important certifications:

ISO 9001:2015 (Since 2019):

• Basic quality management system
• Regular internal and external audits
• Documented procedures for consistency

IATF 16949:2016 (Since 2022):

• Automotive industry standard
• More rigorous quality requirements
• Enhanced process control

While we have these certifications, we’re honest that our implementation is practical rather than perfect. We meet the requirements, but we’re still a traditional manufacturer, not a high-tech facility.

Environmental and Safety Considerations

Responsible Manufacturing

We take our environmental responsibilities seriously within practical limits:

• Metal waste is 100% recycled
• Used oil is collected by certified disposal companies
• We meet local environmental regulations
• Basic safety equipment and training for all workers

We don’t have solar panels or zero-emission goals, but we run a clean, responsible operation.

The Dingli Difference: Why Choose Us?

Honest Advantages

Experience: 30 years means we’ve seen most problems and know how to solve them

Inventory: 6000m² warehouse with real stock, not just promises

Flexibility: We’ll work with your requirements, not force you into our standards

Reliability: We deliver what we promise, when we promise it

Fair Pricing: Competitive without compromising quality

Technical Support: Real engineers with real experience, not call center scripts

Scale: Large enough to handle big orders, small enough to care about every customer

What We Don’t Do (And Why That’s OK)

Honest Limitations

• We don’t offer aerospace-grade documentation (but industrial grade is usually sufficient)
• We can’t trace individual springs (but batch traceability meets most needs)
• We don’t have 24/7 customer service (but we respond within one business day)
• We can’t match the absolute lowest prices (but our quality prevents costly failures)
• We don’t have the latest smart factory technology (but our traditional methods work)

Future Outlook: Steady Growth, Consistent Quality

Our Realistic Plans

Over the next 2-3 years, we plan to:

1. Expand our standard product range to reduce custom orders by 30%
2. Invest in additional testing equipment for better quality assurance
3. Implement basic ERP system for better order tracking
4. Develop partnerships with material suppliers for stable pricing
5. Train younger technicians to maintain our expertise

These aren’t revolutionary changes, but steady improvements that benefit our customers.

Conclusion: Traditional Excellence in Spring Manufacturing

At Cixi Dingli Spring Co., Ltd, we’re not trying to revolutionize the spring industry. We’re focused on what we do best: producing quality springs that meet your specifications, delivered on time, at fair prices.

Our 30-year journey has taught us that customers don’t need fancy technology or marketing promises – they need springs that work. Whether you need 100 pieces or 100,000, whether it’s a standard design or custom specification, we approach each order with the same commitment to quality and service.

We’re traditional manufacturers in the best sense: we value relationships, we stand behind our products, and we’re here for the long term. Your success is our success, and that’s not just a slogan – it’s how we’ve operated since 1995.

Contact Us

Cixi Dingli Spring Co., Ltd
慈溪顶立弹簧有限公司

📧 Email: [email protected]
📱 WhatsApp: +86 13586942004

Send us your requirements – drawings, samples, or even basic descriptions. We’ll give you an honest assessment of what we can do, how long it will take, and what it will cost. No inflated promises, no hidden fees, just straightforward spring manufacturing from a company you can trust.

Frequently Asked Questions

Q1: What’s your actual typical lead time for custom springs?

A: For most custom orders of 1000-5000 pieces, realistic lead time is 10-15 working days from order confirmation. This includes material preparation, production, heat treatment, surface treatment (if required), and quality control. We can sometimes expedite orders for an additional fee, reducing this to 7-10 days. For repeat orders where we have tooling ready, we can often deliver in 5-7 days. Stock items genuinely ship within 24-48 hours – we have the inventory to support this claim.

Q2: How do you handle quality issues if they occur?

A: First, quality issues are rare but not impossible. When they occur, we follow a simple process: 1) Immediate investigation upon notification, 2) Request samples of defective products for analysis, 3) Identify root cause within 2-3 days, 4) Provide replacement products or credit based on the situation. We maintain material and production records for batch traceability. While we can’t guarantee zero defects, we guarantee responsive resolution. Our typical quality issue rate is less than 0.5% of orders.

Q3: Can small companies work with you, or do you only serve large manufacturers?

A: We welcome businesses of all sizes. About 40% of our customers are small to medium enterprises ordering quantities between 500-5000 pieces. While our minimum order quantities exist for economic reasons, we’re flexible. For new customers, we often accept smaller trial orders to establish the relationship. We provide the same quality and service regardless of order size, though unit prices naturally vary with quantity. Many of our long-term large customers started with small orders.

Q4: What information do you really need to provide an accurate quote?

A: The minimum we need: 1) Wire diameter, 2) Outer diameter (or inner diameter), 3) Free length, 4) Required load (or spring rate), 5) Quantity. Helpful additions: Working length, solid height requirements, material preference, surface treatment needs, and application description. If you only have some of these, we can help determine the rest. A sample spring or even a clear photo with dimensions often works. We prefer complete information but understand that’s not always possible.

Q5: How do you compare with cheaper online suppliers?

A: We’re typically 10-20% more expensive than the cheapest online options, but here’s what that extra cost provides: 1) Genuine material certificates, not just claims, 2) Actual quality control with testing reports, 3) Technical support from experienced engineers, 4) Reliable delivery times with real inventory, 5) Consistent quality batch-to-batch, 6) Willingness to handle returns or issues. We’ve seen many customers come to us after problems with cheaper suppliers. The small extra cost prevents production line stoppages, premature failures, and assembly problems that cost far more than the initial savings.