BS 2591-228:2018 pdf download – Aerospace series – Elements of electrical and optical connection – Test methods Part 228: Ferrule withdrawal force
This European Standard describes the procedure to measure the withdrawal force between the ferrule of an optical contact and the resilient alignment sleeve located inside the connector. This method is suitable for use for resilient alignment sleeve qualification. It shall be used together with EN 2591‑100.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 2591‑100, Aerospace series — Elements of electrical and optical connection — Test methods — Part 100: General
3 Terms and definitions
No terms and definitions are listed in this document. ISO and IEC maintain terminological databases for use in standardization at the following addresses: • IEC Electropedia: available at
• ISO Online browsing platform: available at 4 General description The contact force between the mating ferrules in a fibre optic connector is the difference between the breakaway frictional force and the spring force of the connector. To maintain contact, the breakaway friction force shall remain below the spring force. The ferrule withdrawal force is a breakaway frictional force between the ferrule and the sleeve. This force is small and can be affected by numerous parameters like the climatic conditions, the design of the apparatus, the pin gauges, the cleanliness of the specimens, the Van Der Waals forces, and the roughness of specimens.
The criteria to be applied to the results of these measurements account for the spread that is inherent in the preparation of specimens.
5 Preparation of specimens Unless otherwise indicated in the product standard, specimens shall be prepared as below:
• The specimens and apparatus shall be subjected to standard test conditions as defined in EN 2591‑100;
• The specimens and gauge pins shall be perfectly clean and dry;
• Priortotesting,eachsleeveandgaugepinshallbecleanedbywiping,usingforexamplelint-freewipes. The cleaning action shall consist of thorough rubbing or scrubbing. Moistening wipes should be avoided. If moistening is necessary no alcohol shall be used, and following cleaning, adapters and gauge pins are preconditioned at 40 °C for 30 minutes and then returned to room temperature for at least 30 minutes.
• It is strongly recommended to wear gloves to avoid any risk of grease deposit on the specimens and gauge pins.
Unless otherwise indicated in the technical specification, the following details shall be specified in the product standard:
• Min. and max. value of the sleeve withdrawal force in Newton;
• Gauge pin material and dimensions (not required for Zirconia sleeves for ferrule 1,25 mm or 2,5 mm);
• Value and tolerance of the external diameter;
• Length of the chamfer;
• Roughness;
• Roundness;
• Material.
6 Apparatus
6.1 General
The specimen is a connector alignment sleeve. The measurement is made with two gauge pins inserted so they meet at the centre of the sleeve. Force is applied between one of the gauge pins and the sleeve as shown in Figure 1.
The apparatus comprises:
• A force generator with a mechanism that generates a continuously increasing force and is equipped with a force gauge to record continuously the force and the movement of the mobile gauge pin. Loading rates of approximately 100 mm/min are generally considered acceptable for mechanically driven instruments.
• A test assembly with a flexible member to apply the force on the mobile gauge and insure that the force generated will not induce a bending load on the specimen.
• A pair of gauge pins.
6.2 Gauge pin dimensions
The following material and dimensions of gauge pins are defined for Zirconia sleeve dedicated to 1,25 mm or 2,5 mm ferrules. For other sleeves, the dimensions of the gauge pins shall be as specified in the product standard.
• The length of the gauge pin shall be sufficient to allow it to extend half-way into the sleeve and have enough left protruding out of the sleeve to allow for the attachment of a fixture or force generator;BS 2591-228 pdf download.