Spring RFQ Engineering Checklist

1. Identify the part and revision

Name the spring type if known, the mechanism it belongs to and the drawing revision. Include an annotated sketch when the function is difficult to see from the part drawing. Separate dimensions you have measured from dimensions that are design targets.

For a replacement part, explain why a new source or design is needed. An attachment failure, insufficient return and excessive operating force are different problems.

2. Give output at defined positions

For a linear requirement, state force at identified lengths or travel positions. For a rotational requirement, state torque at identified angles or turns. Include units, tolerances where required and the installed starting condition. A single maximum force or torque leaves the rest of the working range undefined.

For a reel, include the drum geometry and the point where cable pull is measured. For a lift, distinguish force at the spring connection from effort at a handle or platform.

3. Show installation and interfaces

• Available housing, arbor and axial space, or the envelope for a wire spring.
• Mounting faces, guides and mating part dimensions.
• Inner and outer attachments or wire-spring leg positions.
• Working direction, preload and travel limits.
• Any friction, gearing, cable or pulley arrangement affecting the spring load.

4. Describe material and operating conditions

State the required grade if one is specified. Otherwise describe moisture, cleaning chemicals, temperature, contact with other materials and the intended finish. Identify the target duty and the failure condition you need to avoid. A cycle target needs operating conditions and an agreed test method before it can become an acceptance criterion.

5. Separate sample and production requirements

Give the sample quantity, expected production quantity and any repeat-order estimate. State which sample measurements need approval. First-time custom parts generally require tooling; sample quantity, MOQ, tooling charges and timing are confirmed for the specific product and design.

If you only have a sample

We can develop a spring from a sample. Send clear photos, overall dimensions and mating mechanism details, together with the performance you need. Let us know whether the sample is new, worn, damaged or modified; we will review its geometry, material requirements and working output together.

We can review PDF, DWG, DXF and STEP drawings. Tell us which files you have in your enquiry, and we’ll confirm how to send them.

Choose the relevant engineering page

Use cord reel springs for rewind requirements, constant force springs for approximately steady pull, or power springs for multi-turn torque requirements. If the type is unclear, start with the mechanism and the available space.