The 3D printer Z offset refers to the distance between the nozzle and the print surface. The Z offset plays a crucial role in determining the quality of the first layer in your print.
The filament won’t flow properly if the nozzle is too close to the print bed, leading to print failure. The filament won’t adhere to the build surface if the nozzle is too close to the print bed.
Calibrating the Z-offset is necessary to maintain the correct distance between the nozzle and the print bed, ensuring first-layer adhesion and setting the foundation for a successful 3D print.
Mastering the art of Z offset calibration requires a mix of technical knowledge, precise measurements, and meticulous testing. But the patience is worth it when you achieve outstanding print quality.
Table of Contents
Understanding Z Offset
Z offset determines the distance between your 3D printer nozzle and the print bed when the build plate is at the Z home position. A proper Z offset height ensures that your first layer sticks well to the print bed, forming a solid foundation for the rest of your print.
If the Z offset is too high, the nozzle will be too far from the print bed, causing the filament to have poor adhesion and increasing the chances of a failed print. On the other hand, if the Z offset is too low, the nozzle may scrape the build plate, damaging both the build surface and the nozzle.
Ideally, the Z offset should be the factory setting without requiring adjustments. However, Slight variations in the limit switch position, build plate thickness, homing probes, manual bed leveling, and auto bed leveling can throw off the Z offset.
It’s essential to adjust the Z offset when changing build plates. For example, if you switch from a spring steel print surface to a thicker glass print bed, you must raise the Z offset to accommodate the thicker material.
It’s important to note that adjusting the Z offset doesn’t replace proper bed leveling. Unless you change build plate materials, you should only need to calibrate the Z offset once. After setting the Z offset, it’ll never need adjusting.
Calibrating The Z Offset
There are three ways to adjust the Z offset of your 3D printer. Let’s look at each option to see what works best for you.
Adjust Z Offset on Your 3D Printer Display
Most 3D printers allow you to calibrate the Z offset directly from the printer’s display. Any 3D printer using Marlin firmware, like the Ender 3, can adjust the Z offset from the display.
Adjusting the Z offset through the display is our preferred method of calibrating it because it is permanent. The Z offset remains calibrated even when you change slicing software.
Here’s how to adjust the Z offset using your 3D printer display:
- Home the printerto position the nozzle at the origin. The origin is usually either the front left corner or the center of the build plate. The homing function on my Anycubic Kobra 2 is at Menu > Leveling > Auto Leveling.
- Disable the motors to manually move the print head. I find it easiest to move the hot end to the middle of the build plate.
- Lower the nozzleclose to the build platform, but not touching. Use the display to lower the nozzle carefully.
- Slide a piece of paperbetween the nozzle and the build platform. You should feel slight resistance when sliding the paper under the nozzle. The nozzle shouldn’t be so low that it interferes with the paper’s movement.
- Adjust the Z offset value until you feel a slight drag on the paper. The nozzle shouldn’t be so far that the paper is loose but also not so close that the nozzle drags on the paper. The options on my printer are at Menu > Leveling > Z Offset.
- Save the Z-offset settingsto save your new Z value.
Some 3D printers allow you to adjust the Z offset while the printer is printing. You can change the Z value while the first layer prints to tune the Z finely offset value. But I prefer the method above.
I don’t like making adjustments while the machine is printing the first layer because it’s challenging to be accurate, and there’s a risk of creating other issues.
If you notice issues with your first layer, it’s best to stop the print and calibrate the Z offset adequately.
Tip: If your 3D printer runs Marling firmware, you can find the Z offset in the “Control” section of the interface. Navigate to the “Control” menu and make the necessary adjustments to the Z offset.
Adjusting With Your Slicer
Slicing software programs allow you to configure your Z offset directly.
For example, you can visit the marketplace in Cura, which features dozens of downloadable plugins. After installing the plugin “Z Offset Setting,” you can adjust your 3D printer’s Z offset under the “Build Plate Adhesion” dropdown.
Setting the Z offset value in your slicer settings is a simple process. But if you change the slicing software, you’ll need to re-configure the Z offset in the print settings before slicing your model.
Adjusting With G-code
You can also calibrate your 3D printer’s Z offset using G-code commands. Changing the Z height using G-code is the most challenging way to adjust the height of your 3D printer nozzle. Like the previous method, you must re-adjust the G-code whenever you switch slicing programs.
Use the following commands to adjust the Z offset with G-code:
- Look for the G28 command in your Gcode and “Z0.” The Z0 command homes the printer. After adding the command, the line should read, “G28 Z0.”
- Find the command that sets the initial Z position, “G92.” After the G92 command, add Z0.1 to give the Z offset a value of 0.1mm. After adding the command, the line should read “G92 Z0.1.”
- Save the Gcode and send it to your printer.
You can raise the Z offset using a negative value like “Z-0.1.” The negative value increases the nozzle by 0.1mm.
You can lower the Z offset using a positive value like Z1, which raises the Z offset by 1 mm.
Remember that if you change slicing software, you must reset the Z offset value.
Fine Tuning the Z Offset
After adjusting the Z offset on dozens of 3D printers, I’ve found trial and error to be the best way to fine-tune the Z offset. It’s a tedious process that requires a bit of patience, but it’s well worth the time and effort for better printing quality.
Start by creating a simple test print, ideally with a single layer and a consistent thickness. I like the Z offset calibration print from Printables for this type of testing.
Another option is to add a cube to your slicing software. Stretch the cube to be the same width and length as your print bed, but set the height to be the same as your layer height. If you’re printing with a 0.2mm layer height, set the height of the cube to 0.2mm.
I prefer using a cube because it allows me to fill the entire 3D printer bed to check for inconsistent layer height.
Editor Note
Before you begin the test print, ensure your printer is properly leveled and the build plate is clean.
Once your test print is complete, carefully examine the first layer. The filament extrusion should be slightly squished but have an overall flat appearance.
Raised ridges indicate that the nozzle is too close to the bed, and you need to increase the Z offset. Gaps between nozzle paths suggest that the print head is too high, so you must decrease the Z offset.
After each print, make minor adjustments to the Z offset and rerun the test print. When you adjust the Z offset, you want to be careful, as significant changes can damage the print bed if the nozzle is set too low.
Remember that negative values raise the distance of the print head from the build surface while positive values lower the print head.
If your nozzle is too close, decrease the Z offset. Lower and negative Z offset valuesmove the nozzle further away from the build plate, preventing the print from being squished.
If your nozzle is too far from the print bed, increase the Z offset. Increasing the Z offset if the nozzle is too close to the print bed. Higher and positive Z offset values move the nozzle closer to the build plate, allowing better print adhesion. Be cautious not to increase the Z offset value too much, as the nozzle can drag on your build plate, causing damage.
