Compression Springs

As a leading spring manufacturer in China, we specialize in producing a comprehensive range of high-quality compression springs at competitive prices. These springs are among our core products, reflecting our commitment to precision, durability, and cost-effectiveness.

What is compression Spring and Technical Details

Compression springs are helical springs engineered to withstand compressive forces along their axis. Renowned for their exceptional energy storage capabilities, these coil springs are versatile components used across a wide array of applications. They can operate independently or be integrated with a guide rod or fitted into a hole. When subjected to a load that compresses the spring, it generates an opposing force, striving to revert to its original length.

The energy stored within a compression spring is influenced by factors such as material properties, wire diameter, and the number of coils. The spring’s stiffness, or rate, is determined by the wire diameter and coil count. This rate, measured in pounds per inch or newtons per millimeter, defines the force required to compress the spring by a unit length. Customization of the spring rate is achievable by adjusting the wire diameter or the number of coils.

Compression springs find applications in diverse fields, including automotive engines, industrial stamping presses, household appliances, lawn mowers, medical devices, consumer electronics, and precision instruments. They are particularly favored in push-button mechanisms, with conical variants being ideal for applications requiring reduced solid height and enhanced resistance to surging.

As a seasoned spring and wire form manufacturer in China, we bring years of expertise to the table. We are pleased to present an overview of compression spring characteristics and our custom spring manufacturing capabilities tailored to your project requirements. Our offerings encompass a variety of materials, sizes, and surface treatments, ensuring that we meet your specific needs with precision and reliability.

Characteristics of compression springs

Custom-Made compression spring

Characteristics of springs

The following figure shows the basic geometric parameters and characteristic relationships of a cylindrical spiral compression spring.

Basic geometric parameters and characteristic relationships of compression springs

F_1,2,3…F_n are the working loads, corresponding to deformations f_1,,f₂,…, f_n. The test load that reaches the torsional test stress τ s is denoted as F_s, and the deformation under the corresponding test load is denoted as f_s. Let the load on the spring during compression be Fb, and the corresponding compression deformation be f_b.In order to ensure stable stiffness of the spring during operation and to guarantee the load at the specified height, the deformation of the spring should be between 20% and 80% of the deformation f_s under the test load, that is

0.2 f_s≤f_1,2,3…n≤0.8 f_s

The corresponding workload should meet the following requirements:

0.2 F_s≤f_1,2,3…n≤0.8 F_s

When there is a special need to ensure stiffness, its stiffness is determined by the ratio of the load difference between two load points and the deformation difference, ranging from 30% to 70% of the deformation f_s under the test load,namely

F=（F₂-F₁）/（f₂-f₁）

F₁ is generally the preload during installation.

Test load

The test cut-off load Fs is the maximum load that the spring is allowed to withstand when measuring its characteristics. Its value can be derived from the curvature coefficient K=1:

F_s=(πd³/8D)τ

If due to raw material and process reasons, when calculating the test load F_s, for ammunition with a twist ratio C ≤ 6, an additional factor can still be added
Curve correction coefficient K.

The value of springs with Class I and Class II loads shall not exceed the maximum test shear stress value or its corresponding maximum test load value.

Solid load

The Solid load F_b is the theoretical load when the spring is compressed, and the corresponding compression and deformation amount is f_b.

F_b≥F_sor f_b≥f_s

Structure of compression spring

Structural types and related parameters of compression springs

Spring end structures come in various types, designed to meet specific operational requirements. When the diameter of the spring material is large, the support figure number should be smaller; conversely, it should be larger for smaller diameters.

A structure where both end rings are tightly pressed together ensures excellent vertical alignment between the end ring and the spring axis, as well as optimal contact with the support seat. This design offers superior working stability. On the other hand, a structure where the end rings are not tightly pressed together is simpler in design. However, to maintain spring stability, it requires a support seat that matches the spring end ring. This type is often used in applications with lower requirements or static loads, as well as for springs with thin wires and large windings.

Empirical evidence suggests that to minimize the impact of load eccentricity, grinding the spring end surface is recommended when the winding ratio is between 3 and 10. For winding ratios between 10 and 15, grinding the end surface is optional, while for ratios greater than 15, grinding is generally unnecessary.

For compression springs made of rectangular cross-section materials, the ends are typically of the contact type, and the end surfaces are ground for optimal performance.

End structure of compression spring

Two ends of coils are closed and ground
Two ends of coils are closed but not ground
Two ends of coils are not tightened
Two ends of coils are closed, ground or not ground
Two ends are flattened and closed, not ground or ground

Spring material diameter

The spring material diameter d should be calculated according to the corresponding formula. If there is a special need, the selected value should comply with the material diameter specification.

Spring coil diameter

The spring center diameter D is the nominal diameter of the spring. The deviation of the outer diameter or inner diameter should be strictly controlled. The deviation value can be found according to the national standard. In order to ensure sufficient space, it should be considered that the spring coil increases after the spring is loaded. When the two ends of the spring collar are fixed and the spring is pressed from the height of the spring to the tightness, the increase in the middle diameter is different.
When the two end surfaces and the support seat can rotate from the height of the spring and the friction force is relatively small, the increase in the middle diameter is also different.

The winding ratio of compression springs (spring index)

The smaller the winding ratio C value, the greater the curvature, the more difficult the winding, the more the shear stress on the inner side of the spring material cross section is greater than the average stress during operation, and the greater the stiffness of the spring. The larger the C value, the opposite is true.

The number of coils of compression springs

In order to avoid excessive additional force caused by load eccentricity, the minimum number of working coils is 2, but generally not less than 3 coils. The number of coils of the support depends on the end turn structure type. The total number of turns n1=n+n2, the last digit of the total number of turns n1 should be 1/4, 1/2 or a full turn, and 1/2 turn is recommended.

The height of compression springs

1) Free height, the free height Ho of the compression spring refers to the height in the free state. Its value is affected by the end structure and it is difficult to calculate the exact value.
2) Working height
3) Test height Hs, which is the height corresponding to the test load Fs
4) Compression height Hb. In principle, it is not specified.

Helix angle and rotation direction of spring

1) Helix angle α

The recommended value is 5° to 9°. If α≥9, the influence of the helix angle should be considered when calculating the deformation.

2) The rotation direction of the spring coil is generally right-handed. In the combined spring, the rotation direction of each layer of spring is the same for left and right rotation, and the outer layer is right-handed

Pitch of spring

Unfolded length of spring material

The wire diameter d, the spring center diameter D and the number of coils n are the three basic parameters of the spring. When these three parameters are determined, the basic performance, strength and stiffness of the spring are determined.

Typical drawings of compression springs

Typical drawing of compression spring

The following figure is a typical drawing of a cylindrical helical compression spring. According to the requirements, the drawing should include technical requirements and design parameters.
Typical drawings of cylindrical helical compression springs

Technical requirements for compression springs

The technical requirements include the following:

Spring end form:
Total number of turns:
Effective number of turns n:
Direction of rotation:
Surface treatment:
Manufacturing technical conditions.
When necessary, the requirements for setting treatment, strengthening treatment, and use conditions such as temperature and load properties can be indicated.

Load types and allowable stresses of Compression Springs

Static load and dynamic load

(1) Static load

1) Constant load:
2) The load changes, but the number of cycles N<104.

(2) Dynamic load

The load changes, and the number of cycles N≥10. According to the number of cycles, dynamic loads are divided into:

1) Limited fatigue life: cold-rolled spring load cycles N≥10~106: hot-rolled spring load cycles
N≥10~103.
2) Unlimited fatigue life: cold-rolled spring load cycles N≥10? times; the number of load cycles of hot-rolled springs N≥
2×106.
When the number of load cycles of cold-rolled springs is between 106 and 10? times, and the number of load cycles of hot-rolled springs is between 10 and 2×106 times, the design can refer to the limited or infinite fatigue life according to the use conditions.

Principles of selection of allowable stress

1) For springs under static load, in addition to considering the strength conditions, if there are requirements for stress relaxation, the allowable stress should be appropriately reduced.
2) For springs under dynamic load, in addition to considering the number of cycles, the stress (change) amplitude should also be considered. At this time, according to the cycle characteristics, when the cycle characteristic value is large, that is, the stress (change) amplitude is small, the allowable stress takes a large value; when the cycle characteristic value is small, that is, the stress (change) amplitude is large, the allowable stress takes a small value;
3) For springs with important uses, whose damage has a great impact on the entire machinery, and for springs working at high or low temperatures, the allowable stress should be appropriately reduced.
4) Springs that have been effectively shot peened can improve fatigue strength or fatigue life.
5) For compression springs, effective strong pressure treatment can increase fatigue life and have a significant effect on improving spring performance.
6) There are many factors that affect the fatigue strength of springs under dynamic loads, which are difficult to accurately estimate. For springs with important uses, tests should be conducted after the design is completed.

Custom Compression Springs Manufacturer in China

At ChinaCustomSpring, we offer the most extensive range of compression springs, backed by cutting-edge CNC self-monitoring and coiling machinery. This advanced technology enables us to produce custom sizes and styles, including variable pitch springs, large compression springs, and more. Our team also provides expert spring design and prototyping support, ensuring your project’s success from concept to completion. With decades of industry expertise, state-of-the-art tools, and an unwavering commitment to quality, we are fully equipped to assist you at every stage—whether you’re in the design phase or scaling up to full production.

Our capabilities are reinforced by advanced quality control systems, regulatory compliance with RoHS, REACH, and DFARS, CAD-assisted product design, in-house prototype production, and a robust global supply chain network. As an ISO 9001:2015 certified company, we adhere to REACH and RoHS regulations and are ITAR registered, ensuring the highest standards of quality and compliance.

Whether you require custom compression springs in small batches or large quantities, we have the flexibility and expertise to meet your needs. From short production runs to high-volume orders, we deliver precision-engineered solutions tailored to your specifications. Trust ChinaCustomSpring to be your reliable partner for all your compression spring requirements.

Material

We provide an extensive selection of materials to cater to the varied demands of our clients. From stainless steel and carbon steel to alloy steel and specialized materials, we offer the versatility needed to meet diverse project specifications. Each material is meticulously chosen for its durability, strength, and resistance to wear and corrosion, ensuring optimal performance and longevity.

Common materials of cold formed springs

Our material offerings include:

High-Carbon Spring Steel Wire: Hard-drawn wire, music wire, and oil-tempered wire, such as 65Mn, 72A, and 82B.
Stainless Steel Wire: Grades 302, 304, 316, and 17-7 PH.
Alloy Steel Wire: Chrome silicon.
Non-Ferrous Alloy Wire: Phosphor bronze, beryllium copper, brass, and Monel.
High-Temperature Alloy: Inconel.
Special Purpose Alloy: Elgiloy, MP35N, and Hastelloy C276.
Non-Ferrous Metals: Copper, tinned copper (Buss), aluminum, and nickel.

With this comprehensive range of materials, we ensure that every compression spring is tailored to meet the highest standards of quality and performance for your specific application.

Wire Diameter

Size tolerance is a crucial factor in the production of compression springs, and we maintain rigorous standards to ensure exceptional dimensional precision. Our dedication to quality ensures that every spring meets industry-standard tolerance specifications, delivering reliable performance and a perfect fit for diverse applications.

We specialize in manufacturing compression springs with wire diameters ranging from 0.1 mm to 20 mm, achieving tolerances as tight as ±0.05 mm. This level of precision underscores our commitment to producing springs that meet the highest standards of accuracy and functionality.

Finish

We provide a comprehensive range of surface finish treatments designed to enhance the performance, durability, and aesthetics of your spring products while saving you time and costs. Our finishing options include:

Plating: Zinc, nickel, silver, tin, chrome, and more.
Anodizing
Black Oxide Coating
Electrophoresis
Powder Coating
Oil Coating
Sandblasting
Polishing
Passivation
And more.

With our extensive finishing capabilities, we ensure your springs meet the highest standards of quality and functionality for any application.

Application

Our compression spring have a wide range of applications across various industries. These springs, known for their ability to store energy when compressed and release it when the force is removed, are integral components in many mechanical systems. Here are some common applications of compression springs we made for our customers:

Automotive Industry
Industrial Machinery
Aerospace and Defense
Medical Devices
Electronics
Furniture
Agricultural Equipment
Garage Doors
Etc

Heat Treatment Hardening for Compression Springs

Heating treatment

Heat treatment hardening is a critical process in the manufacturing of compression springs, aimed at enhancing their mechanical properties, such as strength, durability, and resistance to fatigue. This process typically involves heating the spring material to a specific temperature, followed by rapid quenching and tempering. The result is a spring with improved load-bearing capacity and longevity, capable of withstanding repeated stress cycles. Proper heat treatment ensures optimal performance, making it an essential step in producing high-quality compression springs for demanding applications.

To ensure optimal functionality and durability, the surface treatment of these springs is of paramount importance. At ChinaCustomSpring, a professional spring manufacturer in China, we understand the significance of surface treatment. Therefore, we offer a wide range of common surface treatment methods to meet our customers’ specific needs.

Request A Quote for Compression Springs

We can make a lot kinds of compression spring which made in different shape or material . It’s simple to work with us. Customer only have to offer us drawing or sample, even rough idea is all right. we will quote you best price and offer good quality.

Please provide following information to get a free for custom compression spring:

1.Type of Material:
2.Wire Diameter:
3.Outside Diameter: and Inside Diameter:
4.Free Length:
5.Number of Coils:
6.End Type:
7.Rate:
8.Wire Direction:
9.Finish:
10.Quantity:
11.Other information that is not required but helpful if known

Please refer to the deign of compression springs ,which will be useful to make a custom-made springs

Other types of springs we manufacturing

You can get more information for spring from wiki