1. Printed circuit board (PCB) manufacturers are facing immense pressure to increase density, reduce footprint, shrink size, manage heat dissipation, and enhance data transfer rates, all while improving reliability and cutting costs. As they make progress in addressing these challenges, a new issue has emerged for designers: aligning multiple pairs of connectors between two PCBs.
2. What is needed are clear guidelines for effectively tackling these alignment challenges without compromising system performance, density, or reliability, while also adhering to increasingly tight budget constraints and accelerated time-to-market demands.
3. This article delves deeper into the alignment challenges, highlighting the conflicting requirements that arise between advanced PCBs and high-density, reliable connectors, and offers design practices to help meet these demands efficiently.
**Miniaturization Makes Connector Alignment Challenging**
There are several areas where PCB boards can be improved, such as increased density, higher data rates, better thermal management, and enhanced reliability. However, these improvements come with the challenge of miniaturization, which places additional pressure on designers when selecting and implementing connectors, particularly when multiple connectors are used on a single PCB.
Over the past 25 years, miniaturization has led to a significant reduction in connector spacing, from 0.100 inches (2.54 mm) to 0.016 inches (0.40 mm)—a six-fold decrease that demands tighter tolerances. While tighter tolerances themselves are not inherently problematic, the real challenge lies in the variability around these nominal tolerances. If multiple connectors deviate even slightly from their nominal limits, alignment issues are more likely to arise.
In theory, an unlimited number of connectors can be successfully integrated between two PCBs, provided that sandwich connectors and sufficiently rigid PCB boards can be manufactured, machined, and assembled under controlled conditions. In reality, however, tolerances and material property variability become the limiting factors. As shown in Figure 2, designers must account for tolerances across all components, including the often-overlooked tolerances (A) and (B) of the two PCB boards.
**How to Address PCB-to-Connector Alignment Issues**
For some PCBs, manufacturing is governed solely by specifications embedded in Gerber files, which provide data for PCB fabrication without accounting for mechanical tolerances.
For multi-connector applications, however, the Gerber files must be supplemented with separate mechanical drawings that specify tolerances for drilling, wiring, and other aspects of the board design.
At this point, designers must take two key actions to ensure a successful outcome. First, they should engage with PCB and connector suppliers to determine what alignment support they can offer. Second, designers must conduct system-level tolerance studies to assess the potential alignment deviations of connectors resulting from design constraints. In a multi-connector sandwich card system involving components A through F, the connector supplier can only control the tolerance of the connectors themselves. A reputable supplier will not only meet or exceed published performance specifications but will also offer recommendations on PCB tolerances, machining guidelines, and even suggest trusted PCB manufacturers and equipment when necessary.
Designers should consult the connector’s placeholder size and product specifications, ensuring that any alignment deviation limits specified in these documents align with the results of system-level tolerance studies. This comparison helps ensure that multiple connectors can be reliably used on the same PCB.
The connector system will function properly as long as the allowable initial and final angular and linear alignment deviations are not exceeded. These deviations are determined by factors such as insulator interference, beam deflection, and contact friction. If alignment deviation limits are surpassed, it may lead to disconnections or damage to the circuit or insulator.
Although designers typically have access to all the necessary information, such as design parameters, component tolerances, and manufacturing capabilities, it’s essential to maintain communication with the connector manufacturer. This contact ensures that specific guidance and validation of alignment deviation tolerances are available, helping to avoid costly errors.
**Positioning Pins Are Not Ideal for Multi-Connector Applications**
Some connector manufacturers offer optional positioning pins, typically placed on opposite sides of the bottom of the connector (Figure 4). These pins assist with manual placement, help orient the connector on the PCB, and do not contribute to overall tolerance buildup in single-connector applications. However, they are not suitable for use in multi-connector applications, where precise alignment and tolerance management are critical for success.
If your have any questions about PCB ,please contact me info@wellcircuits.com
2. What is needed are clear guidelines for effectively tackling these alignment challenges without compromising system performance, density, or reliability, while also adhering to increasingly tight budget constraints and accelerated time-to-market demands.
3. This article delves deeper into the alignment challenges, highlighting the conflicting requirements that arise between advanced PCBs and high-density, reliable connectors, and offers design practices to help meet these demands efficiently.
**Miniaturization Makes Connector Alignment Challenging**
There are several areas where PCB boards can be improved, such as increased density, higher data rates, better thermal management, and enhanced reliability. However, these improvements come with the challenge of miniaturization, which places additional pressure on designers when selecting and implementing connectors, particularly when multiple connectors are used on a single PCB.
Over the past 25 years, miniaturization has led to a significant reduction in connector spacing, from 0.100 inches (2.54 mm) to 0.016 inches (0.40 mm)—a six-fold decrease that demands tighter tolerances. While tighter tolerances themselves are not inherently problematic, the real challenge lies in the variability around these nominal tolerances. If multiple connectors deviate even slightly from their nominal limits, alignment issues are more likely to arise.
In theory, an unlimited number of connectors can be successfully integrated between two PCBs, provided that sandwich connectors and sufficiently rigid PCB boards can be manufactured, machined, and assembled under controlled conditions. In reality, however, tolerances and material property variability become the limiting factors. As shown in Figure 2, designers must account for tolerances across all components, including the often-overlooked tolerances (A) and (B) of the two PCB boards.
**How to Address PCB-to-Connector Alignment Issues**
For some PCBs, manufacturing is governed solely by specifications embedded in Gerber files, which provide data for PCB fabrication without accounting for mechanical tolerances.
For multi-connector applications, however, the Gerber files must be supplemented with separate mechanical drawings that specify tolerances for drilling, wiring, and other aspects of the board design.
At this point, designers must take two key actions to ensure a successful outcome. First, they should engage with PCB and connector suppliers to determine what alignment support they can offer. Second, designers must conduct system-level tolerance studies to assess the potential alignment deviations of connectors resulting from design constraints. In a multi-connector sandwich card system involving components A through F, the connector supplier can only control the tolerance of the connectors themselves. A reputable supplier will not only meet or exceed published performance specifications but will also offer recommendations on PCB tolerances, machining guidelines, and even suggest trusted PCB manufacturers and equipment when necessary.
Designers should consult the connector’s placeholder size and product specifications, ensuring that any alignment deviation limits specified in these documents align with the results of system-level tolerance studies. This comparison helps ensure that multiple connectors can be reliably used on the same PCB.
The connector system will function properly as long as the allowable initial and final angular and linear alignment deviations are not exceeded. These deviations are determined by factors such as insulator interference, beam deflection, and contact friction. If alignment deviation limits are surpassed, it may lead to disconnections or damage to the circuit or insulator.
Although designers typically have access to all the necessary information, such as design parameters, component tolerances, and manufacturing capabilities, it’s essential to maintain communication with the connector manufacturer. This contact ensures that specific guidance and validation of alignment deviation tolerances are available, helping to avoid costly errors.
**Positioning Pins Are Not Ideal for Multi-Connector Applications**
Some connector manufacturers offer optional positioning pins, typically placed on opposite sides of the bottom of the connector (Figure 4). These pins assist with manual placement, help orient the connector on the PCB, and do not contribute to overall tolerance buildup in single-connector applications. However, they are not suitable for use in multi-connector applications, where precise alignment and tolerance management are critical for success.
If your have any questions about PCB ,please contact me info@wellcircuits.com
