Introduction

In the realm of Printed Circuit Board (PCB) design, precision, efficiency, and aesthetics are paramount. Altium Designer 17, a leading PCB design software, offers a plethora of features to streamline the design process, one of which is Track Glossing. This feature is often overlooked but plays a crucial role in enhancing the quality of PCB layouts. This article delves into the concept of Track Glossing, its significance, and how to effectively utilize it in Altium Designer 17 to achieve superior PCB designs.

Understanding Track Glossing

What is Track Glossing?

Track Glossing is a feature in Altium Designer 17 that automatically refines the routing of tracks on a PCB. It smooths out sharp corners, eliminates unnecessary vertices, and optimizes the path of traces to ensure a cleaner, more efficient layout. This not only improves the visual appeal of the PCB but also enhances its electrical performance by reducing signal integrity issues that can arise from poorly routed traces.

Why is Track Glossing Important?

1. Improved Signal Integrity: Sharp corners and unnecessary bends in traces can cause signal reflections and impedance mismatches, leading to signal integrity issues. Track Glossing helps mitigate these problems by creating smoother, more consistent traces.
2. Enhanced Manufacturability: PCBs with well-glossed tracks are easier to manufacture. The smoother traces reduce the likelihood of manufacturing defects, such as acid traps, which can occur in sharp corners during the etching process.
3. Aesthetic Appeal: A well-designed PCB is not only functional but also visually appealing. Track Glossing contributes to a cleaner, more professional-looking design, which can be particularly important for high-end products.
4. Time Efficiency: Manually adjusting traces to achieve smooth routing can be time-consuming. Track Glossing automates this process, saving designers valuable time and allowing them to focus on other critical aspects of the design.

How Track Glossing Works in Altium Designer 17

The Glossing Process

Track Glossing in Altium Designer 17 is an automated process that can be applied during or after the routing phase. The software analyzes the existing traces and applies algorithms to smooth out the paths, remove unnecessary vertices, and optimize the overall routing.

Key Parameters

Altium Designer 17 allows users to customize the Track Glossing process by adjusting several key parameters:

1. Glossing Mode: Users can choose between different glossing modes, such as “Weak,” “Strong,” or “Custom.” Each mode applies a different level of smoothing to the traces.
2. Vertex Removal: This parameter controls how aggressively the software removes unnecessary vertices from the traces. Removing too many vertices can lead to overly simplified traces, while removing too few may not achieve the desired smoothness.
3. Corner Smoothing: This parameter determines how the software handles sharp corners. It can round off corners or replace them with curves, depending on the selected settings.
4. Trace Width Consistency: Ensures that the width of the traces remains consistent throughout the routing, which is crucial for maintaining impedance control.

Applying Track Glossing

To apply Track Glossing in Altium Designer 17, follow these steps:

1. Select the Traces: Highlight the traces you want to gloss. You can select individual traces, a group of traces, or all traces on the PCB.
2. Access the Glossing Tool: Navigate to the “Route” menu and select “Gloss Selected” or “Gloss All.” Alternatively, you can use the shortcut keys (Ctrl + G for Gloss Selected).
3. Adjust Parameters: Before applying glossing, you can adjust the parameters in the “Glossing Settings” dialog box to achieve the desired level of smoothing.
4. Apply Glossing: Once the parameters are set, click “OK” to apply the glossing. The software will automatically smooth out the selected traces based on the specified settings.

Best Practices for Using Track Glossing

1. Use Glossing Sparingly

While Track Glossing can significantly improve the quality of your PCB layout, it’s important to use it judiciously. Over-glossing can lead to overly simplified traces that may not meet the design requirements. Always review the glossed traces to ensure they meet the necessary electrical and mechanical specifications.

2. Combine with Manual Adjustments

Track Glossing is a powerful tool, but it may not always produce perfect results. In some cases, manual adjustments may be necessary to fine-tune the traces. After applying glossing, review the traces and make any necessary manual adjustments to ensure optimal performance.

3. Consider Signal Integrity

When glossing traces, pay close attention to signal integrity. High-speed signals, in particular, require careful routing to avoid issues such as reflections and crosstalk. Use the glossing parameters to ensure that the traces maintain consistent impedance and avoid sharp corners that could degrade signal quality.

4. Test and Iterate

After applying Track Glossing, it’s essential to test the PCB design to ensure that it meets all performance criteria. Use simulation tools to analyze signal integrity, and make any necessary adjustments to the traces. Iterate the glossing process as needed to achieve the best possible results.

Advanced Techniques for Track Glossing

1. Differential Pair Glossing

Differential pairs are commonly used in high-speed PCB designs to transmit signals with minimal noise and interference. Altium Designer 17 offers specialized glossing options for differential pairs, ensuring that both traces in the pair are smoothed and optimized together. This helps maintain the required impedance and minimizes skew between the two traces.

2. Length Matching

In designs where trace length matching is critical, such as in DDR memory interfaces, Track Glossing can be combined with length matching tools. After glossing, use the length matching feature to ensure that all traces meet the required length constraints. This ensures that signals arrive at their destinations simultaneously, reducing timing issues.

3. Interactive Glossing

Altium Designer 17 also offers an interactive glossing mode, where you can apply glossing in real-time as you route traces. This allows you to see the effects of glossing immediately and make adjustments on the fly. Interactive glossing is particularly useful for complex designs where precise control over trace routing is essential.

4. Custom Glossing Rules

For advanced users, Altium Designer 17 allows the creation of custom glossing rules. These rules can be tailored to specific design requirements, such as unique trace geometries or specific signal integrity constraints. Custom rules can be saved and reused across different projects, ensuring consistency and efficiency in the design process.

Common Challenges and Solutions

1. Over-Glossing

One of the most common challenges with Track Glossing is over-glossing, where the software removes too many vertices or over-simplifies the traces. This can lead to traces that no longer meet the design requirements. To avoid this, start with a weaker glossing mode and gradually increase the intensity as needed. Always review the glossed traces and make manual adjustments if necessary.

2. Signal Integrity Issues

While Track Glossing can improve signal integrity, it can also introduce issues if not used correctly. For example, rounding off corners too aggressively can lead to impedance mismatches. To mitigate this, use the corner smoothing parameter carefully and ensure that the traces maintain consistent impedance throughout.

3. Manufacturability Concerns

In some cases, glossed traces may not be manufacturable due to the complexity of the smoothing algorithms. To address this, work closely with your PCB manufacturer to understand their capabilities and limitations. Adjust the glossing parameters to ensure that the traces can be reliably manufactured.

4. Performance Trade-offs

Track Glossing can sometimes lead to performance trade-offs, particularly in high-speed designs. For example, smoothing out traces may increase their length, which can affect signal timing. To address this, use length matching tools and carefully balance the benefits of glossing with the need to meet timing constraints.

Conclusion

Track Glossing in Altium Designer 17 is a powerful feature that can significantly enhance the quality of PCB designs. By smoothing out traces, removing unnecessary vertices, and optimizing routing paths, Track Glossing improves signal integrity, manufacturability, and aesthetic appeal. However, it’s essential to use this feature judiciously, combining it with manual adjustments and careful consideration of design requirements.

By following best practices and leveraging advanced techniques, designers can harness the full potential of Track Glossing to create high-quality, efficient, and visually appealing PCB layouts. Whether you’re working on a simple board or a complex high-speed design, Track Glossing in Altium Designer 17 is a valuable tool that can help you achieve your design goals with greater ease and precision.