Die Springs for Mold and Die Tooling
A die spring is the cheapest component in the press and one of the most common causes of a bad setup.
The reason is usually not quality - it is load class and deflection. Two springs with the same free length and the same hole diameter can differ by a factor of four in rate.
The ISO 10243 color code
Danly die springs are manufactured to the ISO 10243 international standard and the NAAMS metric standard, with color coding that identifies the load range at a glance.
| Load class | ISO color |
|---|---|
| Extra Light | Light Green |
| Light | Green |
| Medium | Blue |
| Heavy | Red |
| Extra Heavy | Yellow |
| Ultra Heavy | Silver |
The color is not decoration. Mixed colors in the same die are a mixed deflection profile, and that is how cracked spring pockets and uneven stripper plates start.
Reading the catalog number
Die spring catalog numbers encode the three dimensions the pocket needs: hole diameter, rod diameter and free length. A number in the DieMax XL inch series such as 9-1204-06 carries a 3/4 in. hole, a 3/8 in. rod and a 1 in. free length. Change the free length and the rate changes with it.
All springs are also available unpainted by adding the suffix NP to the part number when color coding is not wanted.
Construction matters to the number as well. DieMax XL springs use high-tensile chrome silicon wire in a rectangular wire design, which is why the same envelope carries more force than a round-wire spring of the same hole diameter.
Deflection is the life decision
Every spring in the catalog publishes a rate - pounds required to deflect one tenth of an inch - and a load-deflection table across three bands.
| Operating band | Deflection |
|---|---|
| Long life | roughly 25-30% of free length, depending on load class |
| Average life | roughly 30-40% of free length |
| Maximum operating | roughly 37.5-50% of free length, with total travel to solid published separately |
Run a spring past its average band and it will still work - for a while. What fails first is free length: the spring takes a set, preload drops, and the die starts leaving parts or stripping poorly. Setting the stroke so the spring operates in the long-life band is the difference between a spring that lasts a campaign and one that lasts a shift.
Sizing order
Pick the hole diameter from the pocket, the rod diameter from the guide pin, then select free length and load class to land the required force inside the long-life band. If the force needed and the space available do not agree, change the class or the pocket - not the deflection limit.
What we stock
Tooling Components stocks the Danly spring line: DieMax XL maximum-life springs in all six ISO load classes and both inch and metric series, Max Life springs, utility springs, urethane strippers and stripping units, Formathane, Marsh Mellow springs, and Kaller gas springs for applications where the force curve has to be adjustable.
Call the counter with the pocket dimensions and the force requirement and we will size the spring off the published load-deflection table. Request a quote or call 814-438-7657.
