bl touch only probs once

3 min read 01-10-2024

The BLTouch is an advanced auto bed leveling sensor that has become popular among 3D printing enthusiasts. However, users occasionally encounter the frustrating problem where the BLTouch only probes once during the leveling process. This article will explore the potential causes of this issue and provide solutions, backed by insights from the community on GitHub, as well as additional tips for optimizing your 3D printing experience.

What is BLTouch?

The BLTouch is an electronic auto bed leveling sensor that helps ensure the first layer of your print adheres correctly to the print bed by compensating for any irregularities. It achieves this by probing several points on the bed's surface, creating a height map that the printer uses during the printing process.

Common Issue: BLTouch Only Probes Once

When users report that their BLTouch only probes once, it can result in uneven first layers and poor print quality. Here are some common questions and answers related to this issue, along with practical insights.

Q1: Why does my BLTouch only probe once?

A1: The BLTouch may only probe once due to incorrect firmware settings or wiring issues. Users often find that their configuration files, such as Configuration.h, need to be adjusted. Additionally, any loose connections or damaged wiring can disrupt the sensor's ability to function correctly.

Q2: How can I troubleshoot this problem?

A2: To troubleshoot the problem, follow these steps:

Check Wiring: Ensure that the BLTouch is correctly connected to the mainboard. Inspect the cables for any damage or loose connections.
Inspect Firmware Configuration: Verify that your firmware is correctly set up for the BLTouch. Look for lines in the Configuration.h file that pertain to the Z probe and ensure they match the correct settings for your sensor.
Testing with the Command Line: Use commands like G28 (home all axes) and G29 (auto bed leveling) through your printer's terminal to test if the sensor responds correctly.

Q3: What are some potential firmware settings to check?

A3: A few key firmware settings to verify include:

#define BLTOUCH: Ensure this is uncommented to activate BLTouch features.
#define Z_PROBE_OFFSET_FROM_EXTRUDER: This should be calibrated to account for the height difference between the extruder and the probe.
#define AUTO_BED_LEVELING_BILINEAR: If you're using bilinear leveling, ensure that this is set correctly to allow multiple probing points.

Q4: What if I've checked everything and it still doesn't work?

A4: If your BLTouch still only probes once, consider the following:

Firmware Reflash: Sometimes, a firmware issue can cause unexpected behavior. Reflashing the latest stable version of your firmware might resolve the problem.
Factory Reset: Restoring your printer to factory settings may clear out any unknown variables that are affecting performance.
Community Help: Check forums, such as those on GitHub, or 3D printing communities to see if others have faced and resolved similar issues. Sometimes, community-contributed solutions can lead to quick fixes.

Additional Tips for Optimizing BLTouch Usage

Regular Maintenance: Regularly clean the probe and surrounding area to ensure accurate readings. Dust and filament debris can affect performance.
Level Your Bed Manually First: Performing a manual bed leveling before using the BLTouch can sometimes help improve overall accuracy, especially in the initial runs after installation.
Use High-Quality Filament: Sometimes, the issue might stem from the print material itself. Using high-quality filament can lead to better adhesion and fewer print failures.

Conclusion

The "BLTouch only probes once" issue can be a common but frustrating problem for many 3D printing enthusiasts. By understanding the potential causes and implementing the troubleshooting steps discussed, users can often resolve the issue themselves. Leveraging community knowledge, such as contributions found on GitHub, can also provide additional insights. Remember, regular maintenance and firmware updates can significantly enhance the performance of your BLTouch, leading to improved print quality and a more enjoyable 3D printing experience.

For more troubleshooting tips, community forums, and documentation related to the BLTouch, consider checking GitHub Discussions for the latest updates and user experiences.

By incorporating a mix of community insights, practical advice, and additional tips, this article aims to equip readers with the information they need to effectively solve the "BLTouch only probes once" issue while optimizing their 3D printing endeavors.