At Southern Spring & Stamping, Inc., we specialize in producing a wide variety of metal fabrications, including compression springs. Throughout more than 60 years of business at our family-owned and operated business, we’ve focused on customer satisfaction and high-quality constructions during every project. Our 100,000 square-foot facility in Venice, Florida ensures our ability to complete high-volume orders in-house and according to our strict quality management standards.
We manufacture and distribute compression springs for a wide variety of industries and applications. We can fabricate high-performing, open-coil helical springs that give process equipment and tools the resistive force they need to operate at their optimal potential. We serve the automotive, aerospace, consumer goods, and a variety of other industries with our comprehensive portfolio of in-house fabrication and finishing services.
What are Compression Springs?
Compression springs are efficient energy-storing tools that offer resistance against compression forces, storing potential energy in their tightly compressed coils and expelling that force upon release. For example, a tool that defaults to an open position can be compressed shut, and then the compression spring will restore the tool to the open position as soon as the compressive force is withdrawn. Due to this primary function, most compression springs have an open coil with space between each repetition of wire so the spring can be forced to compress.
Compression springs come in an extensive variety of types, shapes, materials, and configurations, but the most common variety is a straight cylinder made of either flattened or rounded wire. When choosing the right compression springs for a given application, it’s important to consider different factors such as the spring stress level (how much residual or bending force the wire can safely take on) and the dimensional limits of both the spring and the item housing the spring.
Applications of Compression Springs
As simple and highly customizable items, compression springs have a place in nearly every industry. Some of the most common applications for compression springs include:
- Agriculture: mowers, processing equipment, and vehicles
- Automotive: engines, exhaust valves, seats, suspension systems, and vibration reduction tools
- Consumer goods: cell phones, electronics, mattresses, pens, and toys
- Healthcare: electronics and medical devices
- Industry: electronics, precision instruments, industrial equipment, and mining equipment
Types of Compression Springs
Manufacturers can produce compression springs in different shapes, each of which offers different unique features and advantages. Some of the most popular types of compression spring shapes include:
Conical compression springs are named for their cone shape, with the broader diameter at one end steadily tapering to a smaller one at the other end. One recognizable example of a conical compression springs is the spring used to hold batteries tightly in place in a battery box for small handheld electronics. One of the chief benefits of conical compression springs is how little room they take up during compression. Because of the design, the fully compressed spring is only as tall as the width of the wire itself.
Frequently used in vehicles and furniture, barrel compression springs have relatively narrow radii at both ends of the spring with a much wider middle. These springs are well-known for their stability and resistance to decompression surges.
Hourglass compression springs—also known as convex compression springs—have a larger diameter at both ends of the spring with the width tapering to a narrower diameter in the middle. The ends of the hourglass compression spring don’t need to be the same size. These springs are typically used to center the compression spring over a fixed point, such as a hole.
Commonly referred to as straight-coil compression springs, the most basic form of compression spring is a cylindrical shape with the same diameter of coil throughout. Depending on the nature and type of the spring, it may have no space between the coils or wide areas of space.
How are Compression Springs Manufactured?
When compression springs are manufactured, they start with a design based on Hooke’s Law: F = -kΔx. In this equation, force (F) is measured as the displacement of the spring from its default position (Δx), multiplied by the negative of the spring’s constant (k). Manufacturers control each spring’s constant by changing different design factors such as the diameter of wire and the number of coils in the spring.
Once the design plan is finalized, manufacturers begin to fabricate the wire that will make up the spring. Many springs are made from stainless steel, which can be hardened when it’s in its basic wire form or after it’s been formed into a spring.
While springs were once made using a spinning lathe, this method has mostly gone out of practice because it is less efficient and can also be dangerous. Failing to properly secure the wire can result in damage to equipment or severe injury to the operator.
As such, most springs are formed using an auto-coiler machine. In this method, a long length of wire is introduced to the auto-coiler, which coils the wire into a pre-determined shape, size, and length from a single piece of wire. Wire is spun around a cylinder, and the quick application of force makes the wire adapt and fall into the shape. Once the helical spring reaches the correct length, it is cut and ejected from the machine so the next spring can be made. This is ideal for high-volume spring manufacturing.
While professional spring manufacturers can make almost any type of spring for any application, they need to know all of the design factors and specifications that the spring needs to meet. These specifications may include:
- Helix type. Compression springs can be manufactured with cylindrical, barrel, hourglass, or conical helix types.
- Material. Steel is one of the most common materials for constructing compression springs. This includes high carbon steels, music wire, hard-drawn wire, different stainless steel varieties, and more. Manufacturers can also work with alloys such as chrome silicon and bronze alloys.
- Spring ends type. Most compression springs end the wire in one of these four options: open and ground ends, open and not-ground ends, closed and ground ends, or closed and not-ground ends
- Spring rate. The spring rate measures the change in load per every unit of deflection.
- Stress levels. Compression springs must be able to handle both load and deflection forces. Springs with wide operating stress ranges must have low maximum stress levels, and springs with high maximum stress levels must have narrow operating ranges.
- Wire diameter. The diameter refers to the thickness of the actual wire in the spring, and it can affect the total strength and resistance of the spring.
How to Measure Compression Springs
If you need to reverse engineer the design of an existing compression spring or set the parameters for a new spring design, it’s important to be able to measure a given compression spring. To do so, you must obtain five key measurements from the spring:
- The outer diameter of the coil
- The inner diameter of the coil (either the interior distance of the coil or the outer diameter less two times the diameter of the wire itself)
- The free length (the length of the uncompressed spring)
- The wire diameter, as taken from the center coil of the spring
- The total coil count (including both each full rotation and the remainder of the last coil)
These measurements can be obtained with calipers, a ruler, or a micrometer.
Compression Springs From Southern Spring & Stamping
Compression springs efficiently hold onto force and energy generated by compressing the spring. They can be manufactured in a diverse array of shapes to fit dozens of applications in any industry. Southern Spring & Stamping, Inc. is an ISO 9001:2015-certified company with extensive experience creating long-lasting, high-performance metal springs.
To see how our compression springs can serve your application, please contact us today.