Coiled wire vs. machined: These springs have the same length, outer diameter, and compression rate
If a compression spring application requires the absolutely best repeatability to support calibration or high precision uses, it is best that the coils never touch. Even better, the minimum slot width needs to be wide enough to not permit any interference between the coils from restricting or changing the compression motion. Machined springs are ideal for calibration and precision usages from this standpoint.
The sizes of wire wound springs range from very small delicate springs made from cold forming fine wire to very large, hot-rolled ones that originate as bar stock. This range is quite impressive.
Machined spring sizes are limited by machining practicality. The smallest are about 0.100 inch (2.54 mm) in diameter, and the largest are 6.0 inches (152 mm) across. Maximum length is about 24 inches (610 mm), but this applies to 1.0-inch (25.4mm) to 3.0-inch (76 mm) diameter springs. Smaller or larger diameter springs will need to be shorter.
Wire wound springs can be made very long, as in a garter spring. Length is limited only by the quantity of continuous wire available on the feed spool.
Machined springs, on the other hand, are limited to about 30 coils. Indeed, machined springs with more coils than that are rare.
The sizes of wire wound springs range from very small delicate springs made from cold forming fine wire to very large, hot-rolled ones that originate as bar stock. This range is quite impressive.
Machined spring sizes are limited by machining practicality. The smallest are about 0.100 inch (2.54 mm) in diameter, and the largest are 6.0 inches (152 mm) across. Maximum length is about 24 inches (610 mm), but this applies to 1.0-inch (25.4mm) to 3.0-inch (76 mm) diameter springs. Smaller or larger diameter springs will need to be shorter.
Wire wound springs can be made very long, as in a garter spring. Length is limited only by the quantity of continuous wire available on the feed spool.
Machined springs, on the other hand, are limited to about 30 coils. Indeed, machined springs with more coils than that are rare.
Comparing Features: Wire Wound and Machined Springs
In a coiled spring, the entire length of the wire contributes to elasticity because the forces and moments are distributed end to end.
Machined springs are different. The flexure, the section providing the desired elasticity, is captive between the end sections, which provide structure and attachment features but contribute no elasticity. The slots on machined springs do not taper to zero at the ends. As a result, to accomplish the same elastic performance, machined springs likely need to be longer than wire ones.
Precision is another question to consider. The reality is that precise dimensions are easier to accomplish with machined springs than with wire springs, and precise dimensions are an important part of the foundation for precision performance.
Machined springs are different. The flexure, the section providing the desired elasticity, is captive between the end sections, which provide structure and attachment features but contribute no elasticity. The slots on machined springs do not taper to zero at the ends. As a result, to accomplish the same elastic performance, machined springs likely need to be longer than wire ones.
Precision is another question to consider. The reality is that precise dimensions are easier to accomplish with machined springs than with wire springs, and precise dimensions are an important part of the foundation for precision performance.
Precision: Wire Wound vs. Machined Springs
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