JIS Standard Medium Load Round Wire Die Spring - 37.5% Deflection

This medium-load round wire die spring is used in injection mold and die-set tooling to provide repeatable cavity return force and stable die opening behavior across production cycles.

• Automotive connector and bracket tooling: When inserts or slides must return consistently after each molding shot, the 37.5% allowable deflection ratio helps maintain a predictable force curve within the medium-load range, reducing variability in part ejection timing.
• Consumer electronics housings with tight cycle control: For dies that require controlled material flow and consistent venting/return motion, the round-wire design supports smooth engagement and repeatability in standard die spring pockets.
• General forming and die tooling: Use this variant when your spring stack or die spring cavity is optimized for medium loading and you want predictable deflection under load without oversizing the spring.

Its blue-inch format and medium-load deflection allowance make it well suited for common die spring assemblies where dimensional compatibility and stable force are critical.

The provided data identifies the spring as a JIS standard medium load round wire die spring (DieMax XL™), but it does not specify a steel grade, hardness (HRC), heat treatment, or plating/coating. Therefore, material-property claims such as exact wear resistance or quenched-and-tempered hardness cannot be confirmed from the available specifications.

What can be stated from the documentation is the performance basis: the design is optimized around an allowable deflection ratio of 37.5%, which directly affects the load–deflection behavior and the required spring toughness/elastic integrity for medium-load cycling.

• Material state: Not specified in the supplied parameters (e.g., pre-hardened vs. quenched & tempered, nitrided).
• Wear vs. toughness trade-off: Not specified; selection should be verified with the manufacturer documentation for the required cycle life and operating environment.
• Multiple materials: Not listed for this part in the provided data.

Select the die spring dimensions to match the available space and the required deflection range in your mold’s die return or ejection mechanism. This spring is specified by outer diameter D, inner diameter d, and length L.

• Outer Diameter D (in): choose from 3/8, 1/2, or 5/8 to fit the die spring pocket or guide clearance.
• Inner Diameter d (in): choose from 3/16, 9/32, or 11/32 to clear the locating post/rod and ensure proper alignment.
• Length L (in): select from 1 ~ 12 based on free height and compressed stack height in the closed die condition.

Ensure the working stroke stays within the design’s 37.5% allowable deflection ratio to avoid loss of force predictability. If your assembly has tight constraints, confirm how your pocket dimensions/tolerances relate to the selected D and d; the spring must seat without binding and maintain concentricity through cycling.