How to Troubleshoot Common Spring Problems

How Can You Effectively Troubleshoot and Solve Common Spring Problems?

Springs, despite their simplicity, are subject to various problems that can hinder their performance and lead to system failures. Understanding these common issues is the first step toward effective troubleshooting and maintenance. The most prevalent problems include:

• Taking a Set: This occurs when a spring is permanently deformed due to excessive travel meaning the user went past the safe amount of travel distance causing too much stress, causing it to lose its ability to return to its original length after compression or extension. It leads to a loss of preload, load and travel. Meaning the spring will not perform as it did initially, the spring will be weaker and will continue to degrade over time.

• Corrosion: Springs operating in harsh environments may suffer from corrosion, which degrades the material, reduces the spring's strength, and can ultimately lead to failure. Corrosion is a chemical or electrochemical reaction between the material and its environment.

• Incorrect Sizing:A spring that is not correctly sized for its application can result in insufficient force, excessive stress, or physical incompatibility with the mechanical assembly. This misalignment can cause premature wear by friction, operational inefficiencies, or even catastrophic failure.

By identifying the symptoms and root causes of these problems, engineers and technicians can implement appropriate solutions to extend the life of springs and ensure the reliability of the systems in which they are used.

Spring Taking a Set

What causes a spring to ‘take a set’?

When a spring "takes a set," it means that it has undergone plastic deformation due to exceeding its safe elastic limit. The elastic limit is the maximum safe amount of load and travel to which a material can be deformed and still return to its original shape upon the removal of the load. Exceeding this max safe travel and max safe load limit causes permanent deformation. The primary causes of a spring taking a set include:

1. Overloading: Applying a load greater than the spring's designed maximum safe working load can push the material beyond its elastic limit. This is often due to spring design miscalculations during the design phase of a product or changes in the application that increase the load beyond the original specifications.

2. Improper Material Selection:Different spring materials have varying yield strengths and fatigue limits. Using a material that cannot withstand the operational stresses will lead to deformation. For instance, using a low-carbon steel in a high-stress application where a high-carbon or alloy steel is necessary.

3. Insufficient Stress Relief: During manufacturing, residual stresses can be introduced into the spring material due to processes like coiling and forming. If these stresses are not relieved through proper spring heat treatment temperature with the appropriate amount of time to stress-relieve the spring, they can contribute to the spring taking a set under load. Good stress relief comes from heat treating the springs at the appropriate temperature for that particular material with the appropriate amount of time so the spring material gets tempered. It is like making bread, you make the dough first then you bake it at the right temperature for the right amount of time. In essence what happens when heat treating a spring is the oxygen gets sucked out the springs wire so the spring becomes hardened and elastic, thus giving you the memory or bounce you need in a spring.  

Excessive Operating Temperatures: High temperatures can reduce the yield strength of spring materials, making them more susceptible to deformation under load. Materials not rated for high-temperature applications will deform more readily when exposed to such conditions.

How to prevent a spring ‘taking a set’?

Preventing a spring from taking a set involves a combination of proper design, material selection, manufacturing processes, and operational considerations. Here are detailed solutions:

1. Proper Load Calculations: Accurately calculate the loads the spring will encounter in its application. Use precise engineering formulas or software tools like Acxess Spring's Spring Creator 5.0 to determine the optimal design parameters that will keep the stresses within the elastic limit of the material and the Online Spring Force Tester to test the load capacity of your spring design.

2. Material Selection: Choose a spring material with appropriate mechanical properties for the application. Materials like Chrome Silicon or Stainless Steel 302 offer higher yield strengths and better fatigue resistance, making them suitable for high-stress applications. Consider factors such as tensile strength, modulus of elasticity, and fatigue life.

3. Stress Relief Processes: Implement post-manufacturing processes such as heat treatment to relieve residual stresses in the spring material. Stress relieving involves heating the spring to a specific temperature below its critical point and then cooling it slowly. This process reduces internal stresses and increases the spring's ability to withstand operational loads without permanent deformation.

4. Design Adjustments: Modify the spring's design to distribute stress more evenly. This can include increasing the wire diameter, adjusting the outer diameter, or altering the number of active coils. For example, increasing the wire diameter will enhance the spring's load-bearing capacity but may also affect its flexibility.

5. Temperature Considerations: If the spring will operate in high-temperature environments, select materials specifically designed for such conditions, like Stainless Steel 17-7 PH ASTM A313. Ensure the spring design accounts for the reduction in material strength at elevated temperatures.

Example:

Let's consider a scenario where a compression spring is required for an industrial press mechanism. The initial specifications are:

• Wire Diameter: 0.312 inches 

• Outer Diameter: 4.250 inch 

• Free Length: 8.562 inches

• Total Coils: 10

• Material: Music Wire

• Required Load: 100 lbf

Adding these dimensions on Instant Spring Quote, we get Custom Spring Part Number: AC312-4250-10000-MW-8562-C-N-IN

Upon testing, the spring can handle this load with ease. If we needed a bigger load, we could make these changes:

• Recalculate Loads: Using the Online Spring Force Tester, input the desired load and deflection to verify that the stresses are within the material's elastic limit.

• Select a Stronger Material: Switch to Chrome Silicon, which has a higher yield strength and better fatigue properties. In this case, the spring part number for a similar chrome silicon spring would be AC312-4250-10000-CS-8562-C-N-IN

• Implement Stress Relief: Ensure the manufacturing process includes proper stress-relieving heat treatment to eliminate residual stresses.

Corrosion in Springs

What causes a spring to corrode?

Corrosion is a natural process that involves the gradual destruction of materials, usually metals, by chemical reactions with their environment. Common environmental factors contributing to corrosion include:

• Moisture and Humidity: Water acts as an electrolyte, facilitating the electrochemical reactions that cause rust in ferrous metals.

• Chemical Exposure: Contact with acids, bases, salts, or other corrosive chemicals accelerates material degradation.

• Temperature Fluctuations: Thermal cycling can cause condensation and exacerbate corrosion processes.

• Atmospheric Conditions: Industrial pollutants, marine environments with high salt content, and exposure to corrosive gases like sulfur dioxide can increase corrosion rates.

What happens if a spring corrodes?

For springs, corrosion can lead to:

1. Reduced Strength: Corrosion pits and eats away at the material, diminishing the cross-sectional area and, consequently, the load-bearing capacity of the spring.

2. Surface Pitting and Cracks: Localized corrosion can create pits that act as stress concentrators, promoting crack initiation and propagation under cyclic loading.

3. Complete Failure: Over time, unchecked corrosion can cause springs to fracture or break, leading to system failures that may be dangerous or costly.

How to prevent corrosion in a spring?

To combat corrosion in springs, consider the following strategies:

1. Material Selection: Choose materials inherently resistant to corrosion for the operating environment. Options include:

   • Stainless Steel 302/304: Offers good corrosion resistance in many environments.

   • Stainless Steel 316: Provides enhanced resistance to chloride ion corrosion, making it suitable for marine applications.

   • Phosphor Bronze and Beryllium Copper: Useful in environments where both corrosion resistance and electrical conductivity are required.

2. Protective Coatings: Apply surface treatments to protect the spring material from environmental exposure:

   • Plating: Zinc plating or galvanizing provides a sacrificial layer that corrodes preferentially to the base material. Nickel Plating offers a nice lustrous finish. 

   • Passivation: Enhances the natural oxide layer on stainless steel, improving its corrosion resistance.

3. Environmental Control: Implement measures to reduce the spring's exposure to corrosive elements:

   • Sealing and Enclosures: Use gaskets, seals, or protective housings to isolate the spring from the environment.

   • Dehumidifiers and Climate Control: In indoor settings, control humidity levels to reduce moisture.

4. Regular Maintenance and Inspection: Establish a routine to inspect springs for signs of corrosion:

   • Visual Inspections: Look for discoloration, rust spots, or surface irregularities.

5. Design Considerations: Modify the spring design to minimize areas where corrosion can initiate:

   • Smooth Surfaces: Ensure the spring surface is free from scratches or machining marks that can trap moisture.

   • Avoid Sharp Corners: Round edges to reduce stress concentrations.

Example:

Suppose you are designing a torsion spring for use in a coastal outdoor gate mechanism. The challenges include high humidity, salt spray, and temperature variations. To prevent corrosion:

• Material Selection: Choose Stainless Steel ASTM 316 for its superior resistance to chloride-induced corrosion.

• Protective Coatings: Although SS316 is highly resistant, adding a passivation treatment can further enhance corrosion resistance.

• Design Adjustments: Ensure the spring design avoids crevices where salt and moisture can accumulate.

• Use of Enclosures: Incorporate a protective housing or cover to shield the spring from direct exposure to the elements.

By proactively addressing corrosion through material choice and design considerations, the spring's lifespan and reliability in a harsh environment are significantly improved. Let’s design this spring on Spring Creator 5.0. The initial specifications are:

• Wire Diameter: 0.050 inches 

• Outer Diameter: 0.500 inch 

• Total Coils: 6

• Material: Stainless Steel ASTM 316

• Required Torque: 1.5 in-lbs

By adding these dimensions to the Spring Creator 5.0, we get custom spring Part Number AT050-500-6000-316-RH-0750-N-IN:

Incorrect Sizing of Springs

What causes incorrect sizing in springs?

Incorrect sizing of springscan lead to a myriad of problems, including mechanical failures, inefficient operation, and even safety hazards. The primary causes of incorrect sizing are:

1. Measurement Errors: Inaccurate measurements of critical dimensions such as wire diameter, outer diameter, free length, and total number of coils can result in a spring that does not meet the application's requirements.

2. Design Miscalculations: Misunderstanding or miscalculating the load requirements, spring rate, or deflection can lead to selecting or designing a spring that is either too stiff or too soft for the intended use.

3. Manufacturing Tolerances and Variations: Even with precise design specifications, variations in the manufacturing process can lead to springs that deviate from intended dimensions.

4. Changes in Application Requirements: Modifications in the mechanical assembly or operating conditions without corresponding adjustments to the spring design can result in incompatibility.

How to correct a spring dimension?

To ensure springs are correctly sized and function as intended, consider the following detailed approaches:

1. Accurate Measurements: Utilize precise measuring instruments such as digital calipers, micrometers, and optical comparators to determine the exact dimensions required. Ensure that measurements account for tolerances and are double-checked for accuracy.

2. Comprehensive Design Verification:

   • Use Spring Design Software: Employ spring design calculators and simulation software to model the spring's behavior under load. Tools like Acxess Spring's Spring Creator 5.0 and Online Spring Force Tester can help verify that the design meets all necessary parameters.

3. Specify Clear Tolerances: Clearly define acceptable tolerances for all dimensions and performance characteristics in the design specifications. Communicate these tolerances to the manufacturer to ensure they are achievable and will be adhered to during production.

4. Prototype Development and Testing:

   • Create Physical Prototypes: Before full-scale production, manufacture a small batch of prototypes to test in the actual application environment.

   • Performance Testing: Use Online Spring Force Tester to measure the spring rate, load at specific deflections, and observe the spring's behavior under operational conditions.

5. Consultation with Experts: Engage with spring manufacturers or engineers who specialize in spring design to review and validate the specifications. Their expertise can identify potential oversights or suggest improvements.

6. Adjustments for Manufacturing Processes: Understand that certain manufacturing processes may affect the final dimensions (e.g., plating thickness, heat treatment causing shrinkage). Account for these changes in the initial design.

Example:

An engineer is designing a suspension system for a lightweight electric vehicle. The initial spring design specifications are:

• Wire Diameter: 0.375 inches 

• Outer Diameter: 2 inches 

• Free Length: 10 inches 

• Total Coils: 12

• Material: Stainless Steel 302 A313

By inputting these dimensions into Instant Spring Quote, we obtain a custom spring with Part Number AC375-2000-12000-SST-10000-C-N-IN

After manufacturing, the springs do not provide the expected ride comfort, and the vehicle sits lower than intended. Investigation reveals:

• Incorrect Spring Rate: The spring rate was calculated without accounting for the weight distribution of the vehicle.

• Manufacturing Variance: The actual wire diameter was slightly smaller due to material tolerances.

Solution:

• Adjust Design Specifications: Increase the wire diameter to 0.437 inches and adjust the number of active coils to achieve the desired spring rate.

• Communicate with Manufacturer: Discuss the importance of adhering to specified tolerances and consider selecting a supplier with tighter control over manufacturing processes.

• Prototype and Test: Produce a new set of springs based on the revised specifications and conduct thorough testing to validate performance.

By meticulously verifying design parameters and accounting for manufacturing variations, the engineer can ensure the springs are correctly sized and perform as intended in the application. Let’s try these adjustments on Instant Spring Quote: 

By entering these dimensions into the Instant Spring Quote, we receive a custom spring with Part Number AC437-2000-12000-SST-10000-C-N-IN

Implications of Increasing Wire Diameter

• Increased Spring Rate: The higher wire diameter significantly increases the spring's stiffness, meaning it requires more force to achieve the same deflection compared to the spring with the smaller wire diameter.

• Reduced Deflection Under Load: For a given load, the spring with the larger wire diameter will compress less than the spring with the smaller wire diameter.

• Higher Load-Bearing Capacity: The thicker wire enhances the spring's ability to withstand higher loads without deforming permanently.

Using Acxess Spring's Instant Spring Quote

Designing and procuring the right spring can be a complex process, but tools like Acxess Spring's Instant Spring Quote streamline this task by providing immediate feedback on design feasibility, material options, pricing, and lead times.

Benefits of Using the Instant Spring Quote:

• Time Efficiency: Quickly iterate through design options without the need for back-and-forth communications.

• Cost Transparency: Immediate pricing information helps with budgeting and cost management.

• Design Validation: The tool's calculations help verify that the spring design is feasible and meets performance requirements.

By leveraging the Instant Spring Quote, engineers can efficiently design springs that are precisely tailored to their application's needs, reducing the likelihood of issues arising from incorrect sizing or material selection.

Proactive Strategies for Overcoming Common Spring Problems

Troubleshooting common spring problems is essential for ensuring the reliability and longevity of mechanical systems across various industries. By understanding the root causes of issues like taking a set, corrosion, and incorrect sizing, engineers and technicians can implement effective solutions to mitigate these problems.

Key takeaways from this guide include:

• Spring Taking a Set: Prevented by proper load calculations, appropriate material selection, stress relief processes, and design adjustments to distribute stress evenly.

• Corrosion in Springs: Mitigated through the use of corrosion-resistant materials, protective coatings, environmental control, and regular maintenance.

• Incorrect Sizing of Springs: Avoided by accurate measurements, comprehensive design verification, specifying clear tolerances, and prototype testing.

Uyilizing advanced tools like Acxess Spring's Instant Spring Quote, Spring Creator 5.0 and Online Spring Force Tester empowers professionals to design and test springs with precision and efficiency. These resources streamline the process from concept to production, reducing the potential for errors and enhancing overall performance.

Remember, the key to successful spring application lies in meticulous planning, informed material selection, precise manufacturing, and ongoing evaluation. By adopting a proactive approach and leveraging available technologies, you can overcome common spring challenges and ensure optimal results in your projects.