Connectors for printed circuit boards must be robust, reliably transmit signals and must not fail. Robust connectors for printed circuit boards must be able to withstand mechanical, thermal and chemical stresses such as: - shock, - vibration - oscillation - gas, - humidity, - high temperatures, - moisture, and - dust, without failure. Robust connectors for printed circuit boards are particularly required in the aerospace, industrial automation, automotive and medical technology sectors.
Our PCB connectors use various processes to withstand these loads. Our development department is constantly optimizing our PCB connectors and continuously protecting them against further environmental influences. We ensure consistently high quality by means of numerous test procedures.
Mechanical impacts such as vibration, oscillation and shock - No contact failure with robust connectors for PCBs
Suitable contact system for robust connectors for PCBs
Contact system: Double-sided female connector for PCB connectors
Double-sided spring contact One27 without (left) and with shock impact (right)
Our robust connectors for PCBs have a double-sided female connector that makes board-to-board connectors redundant and contact-safe. The second spring ensures signal transmission via a contact point at all times, even if the PCB connector is subjected to high shock loads. This ensures an optimum device design.
In comparison: classic two-part PCB connectors only have one blade contact and one spring contact. In the event of a strong shock, the male connector may lift off the female connector and interrupt signal transmission.
Contact system: Gender-neutral contact system for PCB connectors
Gender-neutral contact system Zero8
PCB connectors with the "gender-neutral" contact system are much more robust. The special feature of this contact system is that the plug and socket connector halves have identical contact geometries. Each pin is contacted by two springs, plug and socket are interlocked and cannot come loose from each other. This creates maximum redundancy and makes our board-to-board connectors extremely robust and contact-safe. (Fig. 5).
Contact system: One-piece connector for printed circuit boards
One-piece flexilink connector
Only one-piece PCB connectors are even more robust than the gender-neutral contact system of board-to-board connectors.
One-piece connectors for PCBs dispense with the classic two-part contact principle of male and female connectors. They do not have a vulnerable contact area and are therefore extremely resistant to shock, vibration, moisture, dust and atmospheric conditions.
One-piece board-to-board connectors are also suitable for potting and other processes to protect the components of the PCB connector. Combined with press-fit technology, ruggedized one-piece board-to-board connectors provide the most secure mechanical and electrical connection between two PCBs.
Suitable contact design for robust connectors for printed circuit boards
Spring tulip of the One27 after the stamping and bending process
Our robust connectors for PCBs make contact on the female connector, which is bent at 90 degrees.
Advantage: The PCB connector makes contact with the smooth, rolled surface and not on the inhomogeneous and sharp-edged underside of the stamping strip caused by the stamping process. This prevents increased abrasion of the surface and reduces contact resistance.
In addition to the female connector, the male connector of the PCB plug connector must also be punched and processed cleanly so that defective geometries do not interrupt the contact in the event of shock, vibration and oscillation.
Matching insulators for robust connectors for printed circuit boards
The Zero8 connector enables a center offset of ±0.7mm and an angular offset of 4
The insulating bodies of our robust PCB connectors are designed in such a way that the sensitive contacts inside the connector are perfectly protected against shock, vibration and oscillation. Insertion chamfers on the insulating body of the board-to-board connector compensate for any misalignment of the PCBs during mating and allow the connector halves to be mated without damage in the event of a center-to-center or angular misalignment.
Tolerance range for robust connectors for printed circuit boards
Tolerance compensation of the Zero8 in all directions
The tolerance range is another factor influencing the robustness of a PCB connector. If the PCB connector cannot compensate for small tolerances, mechanical micro-movements such as shock, vibration and oscillation will lead to wear or damage to the connector in the medium term. If a robust connector for PCBs has a floating function, it can also compensate for up to ±0.4 mm during operation. This function is becoming increasingly relevant, especially when assembling a PCB with several different connectors.
Low corrosion and abrasion on the surface of robust connectors for PCBs in harsh environments
Abrasion and corrosion of the contact surface
Similar to PCB terminals, connectors with copper pins can easily oxidize with oxygen and ambient moisture alone. Our surface treatment prevents oxidation of the connector pins with a protective layer. The robust board-to-board PCB connectors from ept reduce surface abrasion to a minimum. This leads to less corrosion, less oxide formation and a long service life with many mating cycles.
How do we achieve this despite micro-movements caused by shock, vibration, oscillation, gas, humidity, moisture and dust?
High-quality and durable contact coating of our robust connectors for PCBs
Smooth surface of male and female connectors
The result is low contact resistance and therefore excellent signal transmission from robust connectors for PCBs in harsh environments. This prevents inadequate electrical connections and signal degradation.
We use the following contact coatings, among others:
Gold is an extremely popular contact surface for rugged PCB connectors due to its resistance to corrosion and excellent conductivity, despite rising prices.
Alloy of nickel and phosphorus with gold flash, the price-stable alternative surface. Combined in very specific proportions, these two materials have the same positive properties as gold: high resistance to corrosion, low wear and perfect conductivity.
Gas, humidity, high temperatures, moisture and dust - robust PCB connectors without contact failure
Connectors for PCBs using press-fit technology
The press-fit process
Using press-fit technology, we produce a highly robust and dirt-proof PCB connector that can withstand vibration, shock, gas, moisture, wetness and dust. Robust press-fit connectors for PCBs have a failure rate (FIT rate) ten times better than automated soldered connectors for PCBs. They are used, for example, in airbag systems, ABS and ESP modules, as signal transmission in these applications must not fail under any circumstances.
Press-fit technology generates maximum holding forces between the connector and the PCB with low press-fit force. During the press-fit process, a press-fit pin with a larger diagonal than the hole diameter is pressed into a plated-through hole in the PCB. In the press-fit zone, the connector pin is flexible so that the PCB is not deformed by physical forces during the press-fit process. The result is a cold weld between the contact pin and the metallized PCB hole: a gas-tight, corrosion-resistant, low-resistance and electrically conductive mechanical connection that is also suitable for potting. It is also specified in DIN EN 60352-5 and remains contact-safe even under very high mechanical and thermal loads, such as vibration, bending, moisture, dust and changes in temperature, and even withstands acceleration loads of up to 200 G due to shock. G-forces define loads that act on the human body, an object or a vehicle due to changes in the magnitude and/or direction of velocity. For comparison: after re-entry into the earth's atmosphere, a space capsule is subjected to a G-force of around 7 G.
Connectors for printed circuit boards in SMT (surface mount technology)
Meniscus formation around the soldering foot of the One27
Surface mount technology (SMT) is another option for the stable and reliable connection of connectors and PCBs. They are often used in industrial applications and in Industry 4.0, especially when PCBs are to be assembled on both sides or the minimum distance to components in the direction of force cannot be maintained. Our particularly robust connectors for PCBs in SMT comply with IPC class 3 for use in high-performance electronics. In this class, the transmission of signals must never fail and must transmit higher currents. According to the IPC-A-610 standard, a robust connection between connector and PCB must maintain the correct ratio of solder foot, solder pad and solder paste.
This is how SMT works: solder paste is used to solder the connectors to defined connection surfaces on the PCB, the solder pads. The solder is melted and then hardened in the reflow oven. An optimum soldered connection (SMT) can be recognized by the uniform meniscus formation. The contact must be completely surrounded by solder meniscus in order to achieve the best retention forces on the PCB.
Small, compact yet robust miniature connectors for printed circuit boards
A great deal of know-how through regular optimization and development enables us to build ever smaller and more robust connectors for printed circuit boards. As a result, our board-to-board connectors are becoming ever more durable and efficient, even in ever smaller installation spaces. The small, robust miniature PCB connector from ept guarantees fast, simple and secure signal transmission despite harsh environmental conditions such as shock, vibration, oscillation, high temperatures and dust, and also ensures that the PCB connector is protected against moisture.
With press-fit technology or surface mount technology (SMT), our small, compact board-to-board connectors guarantee a low failure rate and maximum retention forces. Despite their miniature size, small yet robust connectors for PCBs are designed in such a way that, for example, insertion chamfers on the insulator protect the contacts in the event of center misalignment and angular misalignment. During installation, insertion chamfers provide support to enable error-free mating of male and female connectors. This is achieved by the contact and insulator geometry.
Mechanical tests and electrical tests for PCB connectors
There are a variety of test methods for board-to-board connectors, which can vary depending on the industrial environment. Our robust connectors for PCBs undergo the following tests in particular:
Load text for robust connectors
The stress text for ruggedized connectors tests the dielectric strength and contact resistance of, for example, 500 mating cycles before and after stress.
Climatic test for robust connectors
The climatic test for robust connectors checks whether several hours at, for example, -55 °C and then 125 °C have a negative effect on the contact resistance of the PCB connector. This ensures a temperature-resistant PCB connector.
Temperature shock test for robust connectors
The temperature shock test for robust connectors checks whether the board-to-board connector can withstand rapid, extreme temperature changes caused by heat and cold being applied to the PCB connector, for example 100 times for 30 minutes each.
Mating cycles test and noxious gas test for ruggedized connectors
The mating cycle test and the harmful gas test for robust connectors check whether the center offset and angle offset as well as the tolerance range work in practice when mated. The combination of mating cycle test and harmful gas test ensures that the performance of the connector for PCBs has not deteriorated in terms of contact resistance and dielectric strength and that optimum harmful gas protection is guaranteed for the PCB connector.
