There is no denying that installing an auto bed leveling sensor to a 3D printer, such as the BLTouch, is one of the most significant additions to the consistency of the prints and the 3D printing experience of the users, as automatic bed leveling is superior to manual bed leveling in almost every way.
On the other hand, that is not to say that automatic bed leveling does not have some problems of its own either, as correctly installing the sensor and configuring it to get it to work as optimally as possible can have some challenges along the way, similar to many other things in 3D printing.
Today, we will go into the problem of the nozzle remaining too high after automatically leveling the bed with the BLTouch sensor, causing the printing process to fail due to bed adhesion issues resulting from the 3D printer extruding the plastic too far above the build plate.
So, what can cause the nozzle of your 3D printer to stay too high after automatically leveling the bed with the BLTouch sensor?
The most likely reason behind the nozzle positioning itself too high above the build plate after automatically leveling the bed with BLTouch is an incorrectly configured probe Z offset value, which is the parameter that determines the nozzle’s position on the Z-axis.
Moving forward, we will take a deeper look into the reasons that can cause the nozzle to remain too high above the build plate after leveling with BLTouch, how to fix this problem depending on the reason causing it, and quickly take a look at what the optimal distance from the BLTouch to the nozzle should be.
Why Is the Nozzle Too High After Leveling with BLTouch?
As the nozzle starting from a position that is too high above the build plate after automatically leveling the bed is a problem that will cause the printing process to fail, it is vital to find out the reason behind it as soon as possible.
An incorrectly configured Z probe offset value is the most likely culprit behind the nozzle starting the printing process from a position that is high above the build plate after leveling with the BLTouch sensor.
Since the printhead will always position itself according to the position of the Z limit switch after the auto homing process, configuring the Z offset value is necessary to correct the positioning of the nozzle and bring it to its precise position on top of the build plate.
As this behavior is intended, we can consider the probe Z offset configuration process a part of the 3D printer’s initialization process required for the 3D printer to operate correctly.
How to Fix the Issue of Nozzle Being Too High After Leveling with BLTouch?
Fortunately, the process of fixing problems where the culprit is apparent is usually straightforward as it doesn’t require you to spend the time and effort that goes into finding out which one of the potential culprits is causing the issue in your case, which applies here.
Below are the steps we recommend following to fix the issue of the nozzle being too high after automatically leveling the bed with the BLTouch sensor:
- Reset any pre-configured Z offset. You can either do this by using the M851 G-code and passing the Z0 flag to it or in the section that allows you to configure the Probe Offsets through the LCD panel of your 3D printer.
- Bring the printhead to the home position. You can utilize the auto-home functionality through the LCD panel or the G28 G-code, which will automatically bring the printhead to the home position.
- Disable the software endstops. Passing the S0 parameter to the M211 G-code will conduct this process and allow you to set the Z offset to a value that the software endstops might not have allowed.
- Heat the nozzle and the bed to their usual temperatures. You can use the M190 G-code to heat the bed and the M109 G-code to heat the hotend.
- Place a piece of paper under the nozzle, and move the Z-axis down until the nozzle touches the paper. We recommend moving the Z-axis down through the LCD panel as it’s the most straightforward method.
- Note the Z-axis position of the printhead.
- Set the probe Z offset value to the value you have noted in Step 6. You can use the M851 G-code or the LCD panel for this step.
- Re-enable the software endstops. Utilizing the M211 S1 G-code will do the job.
- Save the new probe Z offset value to the EEPROM. You can use the corresponding LCD panel option or use the M501 G-code.
After following the steps above, you can confirm whether the process has been successful or not by homing the printhead again with G28 and using the G1 Z0 G-code to bring the Z-axis to the zero position, where it will start the printing process.
How Far Should the BLTouch Be Positioned from the Nozzle?
Positioning the BLTouch sensor correctly relative to the nozzle of the 3D printer is a vital factor for the BLTouch to operate correctly, as a distance that is too great will cause the BLTouch not to be able to reach the build plate, causing the auto bed leveling process to fail.
The Z-axis distance between the tip of the BLTouch in its stowed position and the 3D printer’s nozzle should be 8 to 8.5 millimeters, and the XY distance between the heater block and the BLTouch’s body should at least be 15 millimeters.
Mounting the BLTouch in a way that doesn’t fulfill these two criteria will prevent the automatic bed leveling function from working correctly and even potentially result in damage being caused to both the BLTouch and the 3D printer.
The nozzle positioning itself at a point that is too high above the build plate after automatically leveling the bed with the BLTouch is definitely a frustrating problem since it causes the entire printing process to fail by preventing the first layer from sticking to the build plate correctly.
To quickly recap, the primary factor that can cause the nozzle to be positioned high above the build plate after conducting the automatic bed leveling process with the BLTouch sensor is an incorrect probe Z offset value, which requires fine-tuning for the nozzle to be positioned correctly.
Fortunately, fine-tuning the probe Z offset value is a pretty straightforward and non-technical process that won’t take much of your time and effort, meaning that you can get your 3D printer back in working condition in no time.