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F E D 2 +

Software for Calculation of Helical Extension Springs

(C) Copyright 1990-2017 by HEXAGON Software, Berlin

Extension Spring Calculation

FED2/FED2+ calculates cylindrical extension springs in accordance with EN 13906-2. Spring characteristic curve, Goodman diagram and temperature diagram can be graphically represented. Scale drawings of the spring, as well as production drawings in accordance with DIN/EN can be exported to CAD via DXF and IGES interfaces. The extended version, FED2+, also contains a database which you can append unlimited, as well as calculation and animation of the spring on screen.


In dimensioning, an appropriate extension spring is calculated from the spring forces, travel, coil diameter and clamping length. In re-calculation, existing springs can be calculated by inputting dimensions. All necessary elements, such as spring forces, travel, spring rates, spring work, tension, wire length, natural frequency and weight are calculated. The greatest and smallest possible wire diameters can be interatively calculated.

Material Database

The software obtains the values for the most important spring materials from the integrated material database (tensile strength, admissable shearing stress in relation to wire diameter, shearing modulus, modulus of elasticity, density).


The program calculates the tolerances for the wire diameter d according to EN 10218 and DIN 2077, and for Dm, L0, F1, F2, F0, eye-overhang, eye position according to DIN 2097 and DIN 2096.

Spring Characteristic Curve

The force path diagram for the extension spring can be displayed on screen, alternatively the tolerance scope of the possible quality grades can be shown.

Goodman Diagram

The working area of the selected materials for the calculated extension spring is shown in the fatigue strength diagram. You can see whether or not the permissable travel tension has been adhered to for dynamically stressed springs. The curves for fatigue strength (>10 million), as well as for 1 million and 100,000 repetitions are shown.

Quick Output

In Quick Output, the characteristic spring curve and the most important spring data are shown on one screen page.

Spring Drawing

You can graphically display spring elevations and cross-sections on screen for any clamping length between L0 and Lc. The graphic display can be exported to CAD via the DXF or IGES interfaces.

Production Drawing

FED2/FED2+ generates a complete production drawing from the calculated data (in accordance with DIN/EN) as DXF and IGES files which can then be exported to CAD.

Spoilage Calculation

FED2+ calculates the wastage quota for all quality grades and stated tolerances based on normal (Gaussian) distribution when you provide manufacturing conditions (e.g. 1% wastage with quality grade 1).


FED2+ animation simulates slewing of the spring on screen between two specified points.

Spring Database

FED2+ contains a database with spring manufacturer catalogues, which you can append with your own springs. After a spring calculation you can search the database for appropriate extension springs when inputting minimum and maximum values.


FED2+ calculates loss of spring loads as function of material, load, temperature, and time.

Wire Profile

FED2 calculates round wire only. FED2+ also calculates tension springs made of square, rectangular and elliptic wire.

Cost Calculation

FED2+ calculates the price for the manufactured spring, the basic data is stored in the database and can be modified.

Hard and Software Requirements

FED2/FED2+ is available as 32 bit and 64 bit application for Windows XP, Windows 7, Windows 8, Windows 10.

Scope of Delivery


HEXAGON gives a 24 month guarantee on full functionality of the software.

Software Maintenance, Hotline

HEXAGON Software is continuously improved and updated. Customers will be informed regularly of updates and new editions.

Download FED2 Demo for Windows XP/7/8/10 (743 kB)

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