Axicom Signal and High Frequency Relays (RF Switches)
APPLICATION NOTE #1
Transportation, Storage, Handling, Assembly and Testing
of Axicom Through Hole Terminal (THT) Relays
Electromechanical relays are robust and reliable electronic components. To achieve desired performance of
Axicom relays, some precautions must be taken during transportation, storage, handling and assembly and testing
of the relays.
Following this guideline enables correct treatment of the relays during the critical phase in the relay life.
A. Transport
In transit, care must 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 specifications in
datasheet). If mechanical stress is suspected, the relay should be checked and tested before use.
Whenever relays arrive in damaged boxes at customer site, there is a potential risk of transportation damage.
Fig. 1: Proper packing of relays for transportation
B. Packaging
Different packaging methods are used depending on the relay type and specific requirements of 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 sticking of the relay to
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. Special care must be taken, so that relays are not
dropped to the floor. Dropped relays shall not be used and must be scrapped.
Axicom /// APPLICATION NOTE
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Transportation, Storage, Handling, Assembly
and Testing of Axicom THT Relays
D. Storage
Relays should be stored in a clean area within the specified temperature limits as indicated in relevant technical
documentation. Extreme humidity and condensation can cause corrosion of the metal parts, both internal and
external.
THT relays do not reach the same temperature level as Surface Mount Terminal (SMT) relays and are therefore not
considered to be moisture sensitive devices.
Increasing contact resistance over time, 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 must 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 must be taken not to bend the relay terminals. Internal failure (e.g. breaking
of coil wires) or the degradation of sealing properties could be a consequence.
F. Automatic handling
The handling pressure or force of automatic feeders or robots must 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 PCB’s, relays shall not be dropped into a bin or on a hard table.
They shall directly be picked from the tube, 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.
Proper and improper release of relays from the tube.
Do not pour relays from tube not
orientated to a hard table
Axicom /// APPLICATION NOTE
Relays shall be placed carefully on a plate and the
plate should be covered with some soft material
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Transportation, Storage, Handling, Assembly
and Testing of Axicom THT Relays
H. Insertion
When inserting the relay into the PCB, do not press or use undue force on the pins as this may compromise the pin
seal or affect the integrity of the coil connections.
I. Clinching
Terminals should not be bent to hold the relay in place on the PCB to aid flow soldering. Bending or cutting the pins
after insertion generates extreme mechanical stress, especially in the case of rectangular PCB terminals. Bending of
pins compromises the relay sealing (of flux resistant, plastic or hermitically sealed) and performance.
J. Fluxing
Fluxing must be carefully considered depending on the type of relay. Unsealed relays must be hand soldered to
avoid flux contamination of the relay. Flux should be used sparingly and evenly and joints should be examined after
soldering. If flow soldering is used however, the flux level should be set so that it cannot flood onto the PCB. This is
critical if the PCB is dual sided and there are unused holes under the body of the unsealed relay. Flux resistant and
sealed relays may be used with most fluxing procedures due to the seal between the pins and the relay base.
The PCB should not be flooded as only the pins are sealed and flux could possibly penetrate the relay by capillary
action between the relay cover and base. If there is any doubt about the fluxing process, fully sealed relays (plastic
or hermetically sealed) should be used.
K. Preheating
Before flow soldering, the entire PCB should be preheated. This is to dry the flux and prevent it from penetrating
the relay during soldering. Also, better quality solder joints are achieved as a result of uniform temperature
distribution. Preheating should be carried out at 100°C for approximately 1 minute. Excessive exposure to high
temperatures may affect the relays characteristics.
L. Wave soldering
The automated soldering process has to be controlled carefully in order not to impair the performance of the relays.
Flux resistant and sealed relays can be used with most dip or wave soldering processes.
The solder bath temperature should not exceed 265°C and the soldering time should not exceed 5 seconds. The
solder level must be adjusted so that it does not flood the printed circuit board surface.
M. Hand soldering
If the relays are soldered by hand, the process should be completed as quickly as possible. The same temperature and
time limits apply as for wave soldering – A tip temperature of 300°C and a soldering time of 3 s shall not be exceeded.
Axicom /// APPLICATION NOTE
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Transportation, Storage, Handling, Assembly
and Testing of Axicom THT Relays
N. Chemical cleaning
In modern PCB assembly process less, cleaning is required as many no clean fluxes are available on the market. If
cleaning is necessary, certain precautions must be taken.
•
Unsealed relays: Only the base of the PCB should be cleaned to prevent penetration of solvent and dissolved
flux into the relay. Any other cleaning method involving potential contamination of unsealed relays should be
avoided.
•
Flux resistant relays: Immersion cleaning is not possible with these types of relays. Only the soldered side
should be washed, and care must be taken not to allow washing solution to flood the PCB surface.
•
Sealed relays: Only fully sealed relays should be immersion cleaned. Even then the PCB should be allowed
to cool before the washing process in order not to damage the seal due to thermal shock or pressure
differential. When using high pressure cleaning processes, special care must be taken to avoid any ingress
into the relay. Liquids under high pressure can damage the seal of the relay.
Ultrasonic cleaning is not recommended as this can cause friction welding of the contacts, more so in case of
gold-plated contacts.
Modern cleaning equipment uses water, alcohol or alkaline solutions, which are more environmentally friendly than
CFC’s. If other cleaning solvents are used, ensure that the chemicals are suitable for the relay. The use of unsuitable
solvents can cause cracking or discoloring of the plastic parts.
Suitable solvents include isopropyl alcohol (alcohol- based solvents), water with wetting agents.
Unsuitable solvents are acetone, ethyl acetate, aqueous alkalines, phenolic combinations, thinner based solvents,
chlorosene-based solvents, trichlene-based solvents and chlorine. Fluor-based cleaning solvents like Freon are
forbidden today.
Special care must be taken on the temperature of the cleaning and rinsing liquid. The temperature of the washing and
rinsing liquid shall be similar and not deviate by more than 10 °C.
Fig. 3: Cleaning of PCB’s. It is most essential to keep the temperature level during cleaning, rincing
and drying constant. The temperature shall not deviate by more than ±10°C.
Ultrasonic cleaning must be avoided for signal relays, as this might result in cold welding of the gold
contacts.
Axicom /// APPLICATION NOTE
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Transportation, Storage, Handling, Assembly
and Testing of Axicom THT Relays
O. Coating
Coating of relays on PCB’s is possible. Only relays which are at least wash tight (RTIII) can be coated. If the relays
that are not wash tight or sealed are coated, there is a high risk that resin will enter the relay and destroy the relay.
Suitable are Epoxy, Urethane and Fluorine coatings. Absolutely forbidden are Silicone coatings.
Fig. 4: Coating of relays on PCB’s
© 2018 TE Connectivity. All Rights Reserved. Axicom, TE, TE Connectivity, and the TE connectivity (logo) are trademarks of TE Connectivity. Other logos, product and
Company names mentioned herein may be trademarks of their respective owners.
While TE has made every reasonable effort to ensure the accuracy of the information in this brochure, TE does not guarantee that it is error-free, nor does TE make any other representation,
warranty or guarantee that the information is accurate, correct, reliable or current. TE reserves the right to make any adjustments to the information contained herein at any time without
notice. TE expressly disclaims all implied warranties regarding the information contained herein, including, but not limited to, any implied warranties of merchantability or fitness for a
particular purpose. The dimensions in this catalog are for reference purposes only and are subject to change without notice. Specifications are subject to change without notice. Consult TE
for the latest dimensions and design specifications.
1-1773931-2 JN 07/2018
Axicom /// APPLICATION NOTE
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