Spring winding services fabricate springs to specifications supplied by their customers. In many cases, spring winding companies also provide design assistance, helping to improve their customers’ designs based on new technologies or by suggesting materials for the applications at hand.

Types of Spring Winding Services

The GlobalSpec SpecSearch database contains information about spring winding services that specialize in these types of springs:

• Compression springs are open coil springs that offer resistance to compressive force. Their uses vary greatly from engine valves to ball point pens.
• Conical springs or taper springs are compression springs in which the spring diameter varies throughout. Their shape allows for more lateral stability than regular compression springs.
• Constant force springs are made from strip material formed in a spiral. They are best suited for counter-balances or applications that require constant pressure.
• Die springs are heavy-duty compression springs designed for high-static or shock-load stresses. They are used primarily in die, tooling, and fixturing applications.
• Disc springs or washer springs are washer shaped springs that apply a pre-load to joints or bearings. They are used when high fatigue life, space utilization, and small spring deflection are desired.
• Extension springs are closed coil helical springs that offer resistance to a pulling force or provide a restoring force to elements that separate during operation.
• Flat springs are made from flat metal strips that store and release energy. Uses include connectors, stops, hinges, braces, and fasteners.
• Garter springs are closed coil springs that form a ring. They are used primarily in oil seals, but also as small motor-belts and electrical connectors.
• Leaf springs are arc shaped metal strip lengths that provide suspension support for cyclic loads. They are used most commonly in automobile suspensions.
• Power springs or clock springs are spiral-wound metal strips that store and release rotational energy. They are used in clock and mechanical motors, rewind devices, and reels.
• Torsion springs exert pressure along a circular path, providing torque. They are wound to fit either inside a hole or around a cylindrical element.
• Variable pitch springs have varying pitch along the length of the spring to minimize resonant surging and vibration. They are used for off-road suspensions and specialized load and deflection requirements.

The GlobalSpec SpecSearch database also provides information about spring winding services that have stamping and wire forming capabilities, or that can fabricate other types of springs.

• Stamping is the process of impressing surface definition and three-dimensional designs onto materials with pressurized tools and dies. It is often an auxiliary service of spring winding companies.
• Wire Forming is the process of drawing and fabricating thin wire into clips, rings, or other process-specific shapes.
• Specialized springs or proprietary springs may require additional service capabilities, including specialty geometry or end configuration.

Spring Selection

The most important attributes to consider when selecting springs are maximum load, working length, tolerance, and deflection.

• Maximum load determines how much force can be applied to the spring before it loses functionality and should be above the load requirements of the desired task.
• Working length is the user defined difference between the length of the fully loaded spring and the preloaded (minimally loaded) spring.
• Tolerance is the amount of deformation and residual stress existing based on spring material properties. Tolerances below the material capability induce extra cost.
• Deflection is the amount of movement within the spring that occurs as a result of an applied force, and must be less than the amount of space the spring mechanism has to operate within.

Material Type

Spring material plays a large role in how a spring functions. Important selection considerations include tensile or impact strength, magnetic and electric properties, and corrosion resistance. Material flow during the stamping or forming process is another significant consideration when deep draws or especially thin or thick parts are desired. When in doubt, the custom spring winding service provider will be able to help with relevant suggestions.

The GlobalSpec SpecSearch database contains these types of spring materials:

• Spring steel is an industrial grade steel that exhibits good elastic and return properties.
• Music wire is an inexpensive high-carbon steel alloy that offers uniform tensile strength.
• Stainless steel exhibits good corrosion resistance for specialty applications.
• Exotic metals and their alloys have some special properties and applications
• Plastic springs are used in light-to-medium duty applications and are both quiet and corrosion-resistant.

References

CNC Zone.com – Spring Winding FYI

F