Manufacturing Process of Cold-formed Springs
As a professional spring manufacturer in China, we wish to explain the details of Manufacturing Process of Cold-formed Springs.When customer design new items, maybe these information are helpful.
No need quenching and tempering
When manufacturing springs that do not require quenching and tempering after forming, the process is as follows:
Spiral Compression Springs:
- coiling,
- stress relief annealing,
- end surface grinding,
- (shot peening),
- (calibration) (stress relief annealing),
- set or stress-relief treatment,
- inspection,
- surface anti-corrosion treatment,
- packaging.
Spiral Tension Springs:
- coiling,
- stress relief annealing,
- production of hooks/rings (end cutting),
- stress relief annealing and setting treatment,
- inspection,
- surface anti-corrosion treatment,
- packaging.
Spiral Torsion Springs:
- coiling,
- stress relief annealing,
- production of torsion arms,
- end cutting,
- stress relief annealing,
- setting treatment,
- inspection,
- surface anti-corrosion treatment,
- packaging.
The manufacturing process for spiral tension and torsion springs described above involves coiling on a regular spring machine, followed by additional processing of hooks/rings or torsion arms at both ends. In recent years, many manufacturers domestically and internationally have started using computerized forming machines or dedicated forming tools, where the body and tail shapes of the springs can be completed in one step, eliminating the need for separate processing of hooks/rings or torsion arms.
Require quenching and tempering
When manufacturing springs that require quenching and tempering after forming, the main difference from the above process is the need for quenching and tempering after forming. Sometimes, the spring ends may also require normalizing treatment.
To improve production efficiency for springs with batch production requirements, production lines are established. Such production lines not only enhance production efficiency and economic benefits but also ensure product quality. Typical production lines include valve spring production lines and suspension spring production lines.
The process flow for a valve spring production line includes:
- coiling, (nitriding),
- (cleaning),
- stress relief annealing,
- (height sorting),
- end surface grinding,
- chamfering,
- initial shot peening (secondary shot peening),
- heating (hot pressing),
- load sorting,
- rust-proof oil coating,
- finished product inspection,
- packaging.
The process flow for a suspension spring production line is as follows:
Cold forming:
- coiling,
- stress relief annealing,
- (hot pressing),
- (inspection using non-destructive testing methods),
- shot peening,
- (hot shot peening,
- stress shot peening),
- (cold pressing),
- load sorting,
- surface coating,
- finished product inspection,
- packaging.
Hot forming:
- material heating,
- coiling,
- (end shaping),
- quenching,
- tempering,
- (hot pressing,
- testing,
- shot peening (once or multiple times),
- cold pressing,
- load sorting,
- surface coating,
- finished product inspection,
- packaging.
Processes in parentheses are non-fixed processes and their execution depends on the performance requirements of the spring.
Coiling is a shorthand term for the coiling-forming process of springs. Coiling is the first and important step in spring manufacturing. The precision of coiling plays an extremely crucial role in the entire manufacturing process, as it essentially determines the dimensions, characteristics, and material utilization of the spring.
Coiling equipment for springs generally consists of shaft-type coiling machines and shaftless coiling machines.
