Q1. What is a compression spring?

A. A compression spring produces a resisting force when compressed. Its common functions include support, cushioning, return, energy storage, and maintaining pressure. In simple terms, it is designed to spring back after being compressed.

Q2. Where are compression springs commonly used?

A. Compression springs are commonly used in buttons, switches, valves, battery holders, tools, machinery, automotive components, home appliances, medical devices, commercial equipment, and automation equipment.

Q3. What information should a customer provide before requesting a quotation for a compression spring?

A. Please provide a drawing with complete dimensions, including wire diameter, inside diameter, outside diameter, and free length.

    - Also specify the end treatment, total number of coils, active coils, winding direction (left-hand or right-hand), material, surface finish,
      compressed height, required force, operating frequency, and operating environment.
    - The more complete the information, the more accurate the quotation will be. A 3D drawing is also helpful if available.

Q4. What is free length?

A. Free length is the natural length of the spring when no external force is applied. If only a compressed height is provided, the uncompressed free length should also be confirmed so the design can be evaluated properly.

Q5. What is solid height?

A. Solid height is the shortest height of a compression spring when the coils are almost fully in contact with one another. The spring should not be kept at solid height for long periods because this may cause fatigue or permanent deformation.

Q6. How can a compression spring be made stiffer or softer?

A. Stiffness can be adjusted through wire diameter, outside diameter, active coils, free length, material, and heat treatment. In general, thicker wire and fewer coils make the spring stiffer, while thinner wire and more coils make it softer. The final design must still match the available space and service-life requirements.

Q7. Is compressed height the same as solid height?

A. No. Compressed height and solid height are different.

     - Compressed height is the height of the spring at a working position during actual use. For example, if the free length is 50 mm and
       the spring is compressed to 35 mm after installation, 35 mm is a compressed height.
     - Solid height is the minimum height when the coils are almost completely in contact with one another. It represents the compression 
       limit of the spring.
     - In simple terms, compressed height is a normal working height, while solid height is the extreme fully compressed height. The spring 
       should not remain at solid height for long periods because this may cause fatigue, loss of force, or permanent deformation.

Q8. What do outside diameter, inside diameter, number of coils, active coils, and required force mean for a compression spring?

A.
    - Outside diameter: the outer diameter of the spring. It affects whether the spring fits within the available product space.
    - Inside diameter: the inner diameter of the spring. It affects whether the spring can fit over a guide post, screw, shaft, or other locating
      component.
    - Number of coils: the total number of coils, including end coils that may not fully participate in elastic deformation.
    - Active coils: the coils that actually participate in compression and affect spring force. Fewer active coils generally make the spring
      stiffer; more active coils generally make it softer.
    - Required force: the force the spring must produce at a specified compressed height. For example, 5 kgf at 20 mm or 30 N at 15 mm.
      For proper spring design, provide both the compressed height and the required force.