AXICOM Telecom- Signal- RF Relays Electromechanical relays are one of the most robust and most reliable electronic components. In order to achieve and guarantee the excellent performance of AXICOM relays, some precautions must be taken during transportation, storage, handling and assembly and testing of the relays. Following this guideline enables proper treatment of the relays during the critical phase in the relay life. A. Transport In transit, care has to be taken to avoid excessive shock and vibration. Mechanical stress can lead to changes in operating characteristics or to internal damage of the relay (see vibration and shock resistance). If mechanical stress is suspected, the relay should be checked and tested before use. Whenever relays arrive in damaged boxes at customer sides, there is a potential risk of transportation damage. Fig. 1: Proper packing of relays for transportation B. Packaging Different packaging is used depending on the relay type and with regard to any specific requirements during shipment or production. THT relays are packed in plastic tubes with stoppers on both sides of the tubes. Plugs on both sides shall be removed especially after long storage time in order to prevent firstly sticking of the relay on the plug and then falling down to the pick place. C. Handling Modern relays are high precision components that are sensitive to mechanical stress and abusive handling. Care must be taken when handling the relay during all stages of production. Especially care must be taken, that relays are not dropped to the floor. Dropped relays shall not be used anymore and shall be scraped. AppNote THT Relays.doc page 1 3/9/2007 AXICOM Telecom- Signal- RF Relays D. Storage Relays should be stored in a clean area within the specified temperature limits. Extreme humidity and condensation can cause corrosion of the metal parts on the inside as well as the outside of the relay. THT relays do not reach the same temperature level as SMT relays and are therefore not considered to be moisture sensitive devices. Increasing contact resistance over a time period, due to the formation of oxides and other layers, is to be expected for most contact materials. This degradation is dependent on the ambient atmosphere and is more rapid at high temperatures. Special care has to be taken if relays are tested or used with low contact loads after being stored for prolonged periods. Deterioration of contact resistance during storage is reduced in the case of plastic or hermetically sealed relays. E. Testing During incoming inspection, special care has to be taken not to bend the relay terminals. Internal failure (e.g. breaking of coil wires) or the degradation of sealing properties could be the consequence. F. Automatic handling The handling pressure or force of automatic feeders or robots has to be adjusted to avoid mechanical damage such as cracking the relay case. The design of the relay should be such that when held by its case or inserted into a socket, it does not become detached. Due to the reduced size of modern Telecom and Signal Relays, they can be placed by pick and place machines with a speed similar to passive PCB components. It is possible to use a mechanical as well as vacuum picker. G. Manual handling When relays are manually placed on PCBs, relays shall not dropped into a bin or on a hard table. They shall directly be picked from the tube, in order to prevent bent terminals and excess mechanical shock. Relays which were dropped to the floor or from a height of more than 250 mm are potentially damaged. After long storage at high temperature it might happen that relays are picking on the plug and are suddenly released. This might cause a major mechanical shock and might destroy the relay. Do not pour relays from tube not orientated to a Relays shall be placed carefully on a plate and hard table the plate should be covered with some soft material Fig. 2: Proper and improper release of relays from the tube. AppNote THT Relays.doc page 2 3/9/2007