Die springs

Alcomex die springs

Die springs (tool springs) are cylindrical helical springs made from oval wire. The dimensions with regard to the installation space and the spring forces show constant values. Thread diameter, number of turns, thread pitch and block length are not specified, since these dimensions require a higher production-related balance.

Function

These springs work just like a normal compression spring. The more it is compressed, the greater the force of the spring. A die spring does not have a round spring wire, but a rectangular variant is used. These rectangular spring wires generate higher forces.

Spring installation

Thanks to its design, this spring can deliver high force in a small space. They have to absorb a high load with a relatively high frequency. Die springs have to withstand strong impacts and are made for a long service life.

The die spring standards

Die springs are subject to DIN standards and must be manufactured with the material: chrome vanadium 50CrV4 as standard.

The color coding is based on the code used in production. The springs are manufactured according to the European standard ISO 10243:2010.

Standard ISO 10243

There are different classes that can withstand different loads. Each of these classes has its own color coding. We produce die springs with the same lengths and diameters so that you can interchange the springs (different color codes). Spring diameters are matched to the specified groove and pin diameters. Diameter, capacity, length and also colors correspond to the ISO 10243 standard.

The ISO 10243 standard defines parameters for compression springs with a rectangular cross-section as follows:

• D outside diameter, equal to the diameter of the housing;
• d inner diameter, equal to the diameter of the guide pin;
• Lo Free Length, the length of the spring at rest;
• R-value (N/mm). This is the load in Newtons (N) required to deflect the spring 1 mm (1 mm 0.04 in; 1 N 0.102 kgf 0.225 lbf).

Color coding

Die springs are characterized by their high strength and short spring deflection. Almost all die spring sizes are divided into 4 color categories, these categories are formed based on the force and stroke of the die springs. Please note the colors given in the table. If a spring with more or less force is desired, it can be used with the same dimensions – but with a different color code – as the spring has the same installation dimensions.

Alcomex offers you 4 spring colors in the catalogue, according to the ISO 10243 standard:

• BV violet, very low load;
• BG Green, low load;
• BA Blue, Medium Duty;
• BR Red, medium duty;
• BY Yellow, heavy burden.
• BB Brown, very heavy burden.

Two strands of springs with ISO standard diameters and lengths but with some distinguishing features:

• Black, extra light load, with working deflections up to 50% of free length;
• BO Orange, super heavy load, for extra large loads.

How to choose the right die spring

Which spring is best suited for the respective situation can be easily determined using the catalog tables, which show the load and stroke in three different examples. The following table shows the values ​​for each product line:

Properties

Thanks to the steel used and the thermal treatment of the springs, all the springs in the catalog have a wide range of uses, these springs can be used at temperatures from -30°C to +250°C.

Materials

Die springs with static or dynamic loads are made from high-quality chrome-vanadium steel 50CrV4 according to ISO10243. This material guarantees a very long service life. By using high-quality chrome vanadium spring steel (50CrV4/DIN 17225/SAE 6150) and a special wire geometry (rectangular wire), maximum compressive strength and service life are achieved.

Die spring tolerances

• Spring constant: ± 10%;
• Free length: ± 1% with a minimum of ± 1 mm;
• External diameter: always smaller than the case diameter indicated in the catalogue;
• Inner diameter: always larger than the diameter of the inner pin specified in the catalogue

The service life can be influenced by dividing the spring travel into working stroke and preload travel. The smaller the difference between spring deflection and unloaded length, the higher the expected service life. Therefore, for maximum service life, the preload should be as large as possible and the spring deflection should be as short as possible.

Guidelines (some things to note)

• As far as the situation allows, the longest spring with the lightest load is preferred;
• A total deflection (preload + working stroke) greater than the maximum deflection specified in the catalog should be avoided. We recommend checking this;
• Always lay out the springs with a pre-compression of at least 5% of their free length (at least 2 mm);
• Place the springs on a surface that will keep them aligned during operation;
• Put the springs in a deep case or route them with an inside pin, especially if L0/D > 3.