One of the main factors affecting 3D printing quality is the position of the nozzle and its distance from the bed.
Cura Z offset helps adjust the Z-axis position of your printer by the provided offset value. In this way, you can adjust the height of the first layer and print on top of an existing model or added materials, such as a glass or magnetic PEI plate placed on the bed.
What Is Z Offset In 3D Printing?
Obtaining perfect prints mostly depends on bed leveling. However, there are times when you have to add a pane of tempered glass or a magnetic PEI bed right after you’ve calibrated the printer’s build plate.
Whatever you add, the plate on top of the bed will add thickness and shorten the distance between the bed and printer’s nozzle. Even a sheet of paper can alter the default distance.
While this may not seem as much, the truth is that a 3D printer’s nozzle is designed to extrude very close to the bed surface.
Thus, any alteration could result in extrusion difficulties and a less-than-perfect first layer. Not to mention that the nozzle could scratch or damage the added pane.
A way to prevent that is by re-leveling the build plate. However, we all know that process is tedious.
This is where the Z offset steps in.
The Z offset setting allows you to change the distance between the nozzle and build surface so that you can make up for the added thickness.
Generally, the Z offset should be equal to the thickness added to the bed. Thus, if the plate you’ve added has a thickness of 0.2mm, that’s the value you should input into Cura’s settings.
However, the Z offset doesn’t have to be a positive value, nor is there a limit to the thickness you can add.
This means that you can add a higher offset value if you want to print on top of an existing model, for instance. A negative offset is useful if you want to position the print head closer to the build plate than true zero.
How To Configure Z Offset In Cura
The Z offset value can be adjusted automatically by the printer’s auto-leveling switch. If your printer doesn’t have such an option or you don’t want to use it, follow the steps below to adjust the value manually.
1. Install Z Offset in Cura
Cura is known as an all-round 3D printing slicer, but most versions don’t have all functions and settings preinstalled.
The Z offset is one of those settings that users might have to install themselves.
You can find a Cura Z offset plugin directly on Ultimaker’s marketplace, or you could download one from a different source, such as GitHub.
Installing a plugin from the marketplace is the quickest way:
- Open Cura and click on Marketplace (top right corner)
- Scroll through the various plugins until you find Z Offset Setting
- Open and click Install
A pop-up window will let you know when the plugin is installed. Close it, then go to Settings and type Z Offset into the search box whenever you have to use this function.
Top tip: Switching your preferences to Advanced or Expert can help you display Z offset in settings. This is the quickest way to find the function and pin it up if you don’t want to search for it every time.
2. Adjust Z Offset Settings
To adjust the offset settings in Cura, you must first know how much thickness is added to the build plate.
The only way to find out the exact thickness is by measuring the additional build surface or the thickness (height) of the object with a caliper.
You can then input this value into the Z offset setting box in Cura.
As a rule of thumb, positive values in this box will raise the print head by the specified distance. For instance, if you insert 0.15mm in the box, Cura will increase the distance between the nozzle and build plate by 0.15mm.
A negative value in this box will lower the nozzle – this is helpful if you want to squish the first layer of material.
Note: You can also calibrate Z offset from the G Code or your printer’s settings. To change Z offset from G Code, set the Z-axis height for linear movement and insert a command so that the printer considers that height as 0 position until the axis is homed.
- G1 Z0.1
- G92 Z0
In the code above, the first line tells the printer to set the Z-axis height at 0.1mm. The second line tells the printer to consider that position as 0mm until the axis is homed.
The exact procedure for adjusting the Z offset directly from your printer’s screen varies from printer to printer. You should check your user manual to learn how to calibrate it.
3. Check Calibration
If you’ve measured the additional build surface or object correctly, the Z offset should be right. The only way to verify this is by starting a print.
Watch the extrusion of the first layer after adjusting the Z offset. In case of over-extrusion, the Z-axis is set too high and must be lowered. Z banding is another sign of over-extrusion and a telltale that you must lower the Z offset.
In case of under-extrusion, the Z-axis is set too low and the nozzle struggles to extrude material correctly. You should raise the nozzle.
Benefits Of Using Cura’s Z Offset Feature
Setting a positive or negative Z offset in Cura comes with multiple advantages over adjusting this setting from the printer’s screen or the G Code.
Simple Offset Calibration
Undeniably, the main advantage of adjusting the Z offset in Cura is the straightforward method of calibrating this setting.
All you have to do is to install the plugin and input the desired negative or positive value. You don’t have to understand the G Code nor alter any default Z-axis settings on your printer’s firmware.
Easier Bed Leveling
As explained, changing the Z offset in Cura can help you level the bed without actually recalibrating it. This can save you time, especially if you’re in a hurry or if you’re a beginner.
Improved Print Quality
An unleveled bed is one of the main reasons your prints don’t look as good as they should.
However, the problem could be a change in the bed position prior to printing, such as a sudden lowering of the bed for some reason or a decision to use an additional build surface.
In these circumstances, adjusting the Z offset can help you mitigate the issue and create higher quality prints.
The Z offset can also help when you can’t set the nozzle close enough to the build plate. In this case, a negative offset can solve the problem.
Printing On Top Of Objects
While Z offset adjustments are usually made to compensate for bed leveling issues or the thickness of an additional build surface, you can also use this setting to print on top of already printed objects.
For instance, you may want to change the offset if you’ve decided to switch to a different type of filament mid-print.
Printing Process Control
Ultimately, Cura Z offset offers unparalleled control over the printing process.
You can decide to raise the axis if you want to over-extrude material. If for some reason, you’re aiming for under-extrusion (for instance, if you’re printing with particularly difficult filaments such as PETG), you can lower the axis through Z offset and avoid problems like elephant foot.
Since you won’t have to change the firmware code, you can easily revert to the original settings whenever you wish.
Commonly Encountered Issues With Z Offset
Cura’s Z offset comes with multiple advantages, but that doesn’t mean it’s error-proof. Here are some of the most common issues and how to solve them.
Cura Z Offset Not Working
Firmware incompatibility is one of the main reasons the Z offset setting is not working in Cura. That’s because the slicer and firmware can’t communicate properly.
Updating your 3D printer’s firmware can usually solve the issue.
If your firmware is updated and the Z offset is still not working, check the Cura version that you’re using. If necessary, update to the latest version.
Incorrect Z Offset Values
Incorrect Z offset values rarely happen when inputting a positive offset. In this case, the printer will simply raise the print head to the specified value.
However, a negative offset can trigger errors.
This is usually due to a negative that is lower than the Initial Layer Height as set in your 3D printer.
For instance, if your initial layer height is 0.3mm, you can enter a Z offset as low as -0.3mm. With this value, the printer lowers the nozzle so that its tip touches the build plate.
However, if you set -0.6mm, for instance, the firmware’s G Code will simply ignore the value or trigger an error.
To avoid this problem, check the Initial Layer Height before setting a negative Z offset.
Nozzle collisions are the result of an incorrect Z offset setting.
If you adjust the Z offset and then add another layer to your build plate, the nozzle will likely collide with the new material. An incorrect measurement of any additional thickness can result in the same problem.
Mistakenly setting a negative offset rather than a positive one can result in nozzle collision.
An easy way to avoid issues is by paying attention when calibrating this parameter.
Should Z offset be negative?
The Z offset should only be negative when you want to lower the nozzle and diminish the distance between it and the bed. If you want to raise the nozzle, the offset value should be positive.
How far should the nozzle be from the print bed?
For most materials, the nozzle should be around 0.1mm from the bed. You can check if this is the right distance by printing the first layer. If the nozzle plows through the material causing a rough, uneven surface, you should raise the Z offset.
Cura’s Z offset comes as an alternative to Z-axis offset changes from the G Code or printer’s screen. The function is easy to use once the plugin is installed and enhances your control over the printing process. Hopefully, this guide can help you install, use, and troubleshoot Z offset in Cura.