One of the core steps in 3D printing is slicing. A good 3D printing slicer software must have a high degree of freedom to fully utilize the designer's ingenuity and the 3D printer's performance. Cura, published by Ultimaker's official team, is one such software. It not only allows for initial settings but also has an advanced mode for users to fine-tune various printing parameters and details, such as layer height, supports, infill density, print speed, etc. All kinds of settings can be found, allowing 3D printing enthusiasts to unleash their maximum creativity. Below is a tutorial for Cura 15.04, the most widely used version, which I'd like to share with everyone!
Installation
Please download and install Cura 15.04 from the official website. Before installing, remember to check the following points to ensure your computer system is compatible!
Operating System
• Windwows Vista and newer
• Mac OSX 10.7 and newer
• Linux Ubuntu 15.04, Fedora 23, OpenSuse 13.2, ArchLinux and newer
Processor
• OpenGL 2 compatible graphics chip
• Intel Core 2 or AMD Athlon 64 or newer
File Types Supported
• STL (most common 3D print file format)
• OBJ
Interface Configuration
The first time you open Cura, you need to select the 3D printer you are currently using. If you are using Ultimaker Original or Ultimaker Original+, you must complete the "configuration wizard" for interface setup.
Original and Original+ Configuration
The “configuration wizard” will assist you with machine calibration and preparing for your first print. It basically performs the following checks:
- Connect to computer via USB
- Heat nozzle
- Check homing sensors
You will also be guided by the “bed leveling wizard” to set the print bed height. After setting, you can print a small cube on the bed to check the calibration.
Operating Interface
The image below shows Cura's operating interface and some of its most important functions. You can set your preferred print parameters in Cura and then slice your object.
1. Menu bar: Access various preference and machine settings.
2. Quick Print menu: Preset print options.
3. Support structure: Choose whether to add supports.
4. Load object: Open your 3D object file with Cura.
5. Save sliced model: Save the sliced object to your computer or SD card (default to SD card).
6. YouMagine button: Share your file with the YouMagine.com community.
7. View mode: Use view mode to check the feasibility of your design and print path.
8. Rotate: Rotate your object along the X, Y, and Z axes.
9. Scale: Adjust the size of the object.
10. Mirror: Mirror the object along the X, Y, and Z axes.
Preparing Print Files
The first time you open Cura, you will see an Ultimaker robot in the center of the platform. You can save it as a printable g.code file or right-click > "Delete object" to remove it.
File Slicing
Here's the process for slicing a 3D object using Cura:
1. Click "Load" to import a 3D object (STL, OBJ, DAE or AMF file).
2. Select a "quickprint" preset print option, or click "Expert" > "Switch to full settings" to control more parameters.
3. After setting the parameters, Cura will slice in real-time. Then click "Save toolpath" to save the g.code file to your computer or SD card (default).
4. Finally, remove the SD card from your computer and insert it into the Ultimaker to start printing.
Below the "Save toolpath" icon is the print information. Cura estimates the print time, filament usage, and object weight based on the print parameters.
NOTE: You may notice a slicing progress bar. Whenever parameters are changed or an object is reloaded, a slicing progress bar will appear below the "Save toolpath" icon, showing the slicing completion status.
Quick Print Configuration
Here are the four settings for quick print configuration:
Fast print
Layer height: 0.15 mm
Shell thickness: 1 mm
Infill density: 10%
Normal quality
Layer height: 0.1 mm
Shell thickness: 0.8 mm
Infill density: 20%
High quality
Layer height: 0.06 mm
Shell thickness: 0.8 mm
Infill density: 20%
Ulti quality
Layer height: 0.04 mm
Shell thickness: 0.8 mm
Infill density: 20%
Adjusting Objects
Cura provides several methods for adjusting objects before printing. This doesn't mean you can change the object's actual shape, but you can change its position and size.
Rotate
The leftmost icon at the bottom left of the interface is the rotate function. Clicking the rotate function allows you to rotate the object along the X, Y, and Z axes. By holding down the left mouse button on one of the axes, you can move it 15 degrees at a time; or, by simultaneously holding down the "Shift" key, you can move it one degree at a time.
Click the "Rotate" icon, and two other icons will appear above it: "Reset" to return the object to its original position; if your object doesn't have a clear flat surface or is loaded at the wrong angle, you can click "Lay flat": Cura will automatically place the flatter side of the object on the print bed.
Scale
The middle icon at the bottom left of the interface is the scale function, which allows you to scale the object along the X, Y, and Z axes. Here are a few ways to operate it:
• Drag the small square on any axis of the object to scale it.
• Directly adjust the size values in the "Scale" function.
• Adjust the percentage in the "Scale" function to scale it.
The default scaling is uniform scaling along the X, Y, and Z directions. You can uncheck "Uniform scale" to adjust the dimensions of each direction independently.
Above the "Scale" icon, there are also "Reset" and "Scale to max" icons. "Reset" returns the object to its original size; "Scale to max" scales the object to the maximum printable size within the printable area.
Mirror
Click on the object, and the rightmost icon at the bottom left of the interface is the mirror function. Clicking the mirror function allows you to mirror the object along the X, Y, and Z axes.
View Mode
Clicking "View mode" in the top right corner of the interface will display multiple options for viewing objects.
Normal
This is the default viewing mode, showing the object's design, size, and shape.
Overhang
In this mode, if your object has overhanging or sloped parts, these parts will be displayed in red, allowing you to easily determine if they need supports. You can select "Expert" > "Switch to full settings" > "Basic" > "Support type" > "Overhang angle for support" to set the degree of overhang that requires supports. The default is 60 degrees (0 degrees is vertically upward), meaning supports will be generated for overhangs greater than 60 degrees. Setting it to 0 degrees means all overhangs will get supports, and 90 degrees means no supports will be generated.
Transparent
This mode allows you to observe the internal structure of the object.
X-Ray
This mode helps you identify if the object has fractured surfaces (which might be due to improper design). The red areas are where printing problems might occur.
LAYERS (Layer View or Slicing Mode)
Layer mode (or slicing mode) is a very practical mode where you can view each sliced layer. It is recommended to open this mode before printing to check for any issues after slicing the object. Note: In layer mode, moving the slider on the right up and down allows you to view each layer.
The different colors you see in layer mode represent different meanings:
• Red: Outermost perimeter of the object (outer wall)
• Green: Second layer of the outer perimeter (inner wall)
• Yellow: Infill
• Blue: Support structure / Brim / Raft
Firmware Update
From time to time, new versions of Cura (including new firmware versions) are released on the official website. It is recommended to regularly check the official website to keep Cura and the machine's firmware updated to the latest version. Please follow these steps to update the firmware:
1.Connect
Connect your computer to the Ultimaker with a USB cable. Remember that Ultimaker 2 series and Ultimaker Original+ machines must be powered on and connected.
2.Update Firmware
Open Cura and go to “Machine” > “Install default firmware” (please ensure the correct machine is selected in the “Machine menu”). Cura will automatically update the latest firmware version to the machine.
Basic Print Parameters
Under the Basic tab, you'll find some of the most frequently used parameters. These parameters are the primary factors determining the print quality and strength of your object.
Quality
Layer height is probably the most commonly changed setting. The default layer height is 0.1mm. You can, of course, use a finer layer height for increased quality, or a thicker layer height to shorten print time.
You will also see the "Enable retraction" option checked by default. Retraction means that when the nozzle moves to a space where it doesn't need to print, the filament is automatically pulled back a small distance. For example, when printing two pillars with a certain distance between them, retraction ensures that the nozzle only moves and does not extrude any plastic, preventing "stringing" (fine plastic strands between different parts). The image below shows stringing that occurs if retraction is disabled.
Usually, enabling retraction yields good results, but you might still occasionally see some stringing. In such cases, you can try lowering the nozzle temperature to reduce the amount of plastic flowing out of the nozzle, thereby preventing stringing. However, please note that lowering the nozzle temperature also means you (possibly) need to slow down the print speed to ensure the plastic is fully melted when it leaves the nozzle.
Fill (Infill Density)
Infill density is most related to the strength of the printed object. Higher infill density means more plastic infill inside the printed object, resulting in a stronger object. In some specific cases, you can also print completely hollow objects.
Bottom/Top thickness determines how many layers are printed for the bottom and top of the object. It is usually set to 0.6mm, but in some special cases, it may be necessary to increase the thickness. For example, if you are printing a large, flat top surface, or if your object requires a low infill density, a thicker top layer is needed to seal the object.
SPEED AND TEMPERATURE
Print speed and temperature have a significant impact on plastic extrusion, and their settings largely depend on the filament used. Print speed basically refers to the nozzle's movement speed during printing, and the amount of plastic to be extruded is calculated based on this speed. The default print speed is 50mm/s, and you can, of course, increase it to speed up printing. Remember that print temperature should also be increased with print speed to ensure a sufficient amount of plastic is melted.
If you select Ultimaker Original or Ultimaker Original+ as your machine in Cura, you will also see the "printing temperature" option. Please adjust the setting according to the filament being used. For the Ultimaker 2 series, all filament settings have been moved to the machine itself.
SUPPORT
Some objects have overhanging parts, meaning you will need to add support structures to prevent these parts from sagging or falling. Cura offers two support placement options: "Touching buildplate" and "everywhere". "Touching buildplate" supports only connect to overhanging parts that can directly touch the print bed. "Everywhere" supports not only connect to overhanging parts that can touch the print bed but can also be generated on the object's surface or within it.
If the bottom of your object is uneven, or if you want to increase adhesion between the object and the print bed, you can choose one of the platform adhesion types: Raft. A Raft creates an additional grid-like structure between the object's bottom and the print bed. This function is very suitable for printing objects with uneven bottoms or small contact areas to ensure adhesion between the object and the bed. Brim refers to printing several additional plastic lines extending outwards from the first layer of the object. These extra printed plastics are attached to the object and serve to increase the object's bottom surface area to enhance adhesion between the object and the print bed, reducing warping.
FILAMENT (ONLY UMO/UMO+)
If you have selected Ultimaker Original or Ultimaker Original+ as your machine in Cura, this option will be available for adjustment. Ultimaker's own brand filaments are all 2.85mm in diameter. If you use filaments from other suppliers, you may need to adjust the filament diameter setting in Cura. You can also further adjust FLOW, which regulates the amount of plastic extruded based on print speed and filament diameter. Unless you are specifically testing, it is generally recommended to keep this setting at 100%.
MACHINE
This option allows you to adjust the nozzle diameter. Ultimaker defaults to a 0.4mm nozzle diameter. If your Ultimaker uses an Olsson block and you have other nozzle diameters available for change, remember to modify this setting to match the nozzle currently in use.
Expert Settings
For experienced users, there are also some expert settings available for adjustment. General users typically won't need to use these, but if you are an advanced user, you might be interested in more advanced settings.
You can find small "..." squares next to some options under the Basic and Advanced tabs. Clicking these squares allows you to adjust expert settings.
RETRACTION
In this section, you can adjust settings related to filament retraction. Generally, the default values work well, but for better quality, you might need different retraction settings when using different filaments.
SKIRT
A skirt refers to printing a contour around the first layer of the object. This function helps the nozzle prime and checks bed leveling, filament adhesion, and extrusion status. In some cases, you might want to adjust the skirt's expert settings, for example, when printing an object with a base the same size as the print bed and repeatedly checking bed leveling.
COOL
After printing the first few bottom layers, Ultimaker defaults to full cooling fan speed. However, you can adjust this in Cura, which might be helpful especially when printing with different materials that require different temperatures and cooling levels.
INFILL
In addition to setting the infill density and bottom/top layer thickness, more advanced settings can be modified, with "Solid infill top" and "Solid infill bottom" being the most commonly used. If you uncheck either of these, the bottom or top cover of your object will not be printed. For example, unchecking "Solid infill top" and setting infill density to 0% allows you to print a vase.
SUPPORT
In some special cases, it is advisable to use support settings other than the default, but not too far off from the default values. Adjusting different support structures, overhang angles, and distances between supports can generate more or stronger supports, which can yield better results depending on the object.
BLACK MAGIC
Generally, the print bed lowers slightly after each layer is printed, allowing you to print the next layer. Alternatively, you can check "Spiralize the outer contour" in this option. This function allows the bed to lower slowly and at a constant speed, like printing a spiral object. It's particularly useful when printing single-walled objects.
BRIM
You can modify the Brim; more lines mean a larger Brim area and better adhesion with the platform. In most cases, the default 20 lines are sufficient.
RAFT
A Raft is an additional grid structure built between the bottom of the object and the print bed. This function is very suitable for printing objects with uneven bottoms or small contact areas to ensure adhesion between the object and the bed. Raft's expert settings have many parameters that can be adjusted, and they will not be introduced one by one here. If you frequently use Raft, experimenting with these settings will be very helpful.
FIX HORRIBLE
If an object is designed incorrectly, the Ultimaker's output may not be exactly what you intended, for example, if some objects have gaps or overlaps. The Fix horrible setting is usually used to repair these errors on objects. You may need to try different combinations of options and check them through the Layers view.
Advanced
Settings under the Advanced tab typically only need to be modified when default values are insufficient to meet your specific needs.
RETRACTION (ONLY UMO/UMO+)
This option shows the retraction speed and distance of the filament. Generally, the default values work well, but for better quality, you might need different retraction settings when using different filaments.
QUALITY
Some settings related to layer separation and quality of the printed object. "Initial layer thickness" refers to the thickness of the first layer of the printed object. The default is a somewhat thick 0.3mm, but it makes the first layer easier to print and adheres better to the platform. "Cut off object bottom" is a very convenient function that allows you to print without starting from the first layer. If your object has an uneven bottom or if you only need to print a portion, you can use this function.
SPEED
In addition to the basic speed set under the Basic tab, you can set the print speed for specific parts here. For example, you can set separate print speeds for infill structures and bottom layers.
COOL
Plastic cooling is very important, so there are several cooling-related parameters that you can adjust as needed. The fan is set to turn on by default during printing. "Minimal layer time" is defaulted to 5 seconds, which you can modify. "Minimal layer time" refers to the minimum time required to print a single layer, ensuring that the extruded plastic has enough time to cool before the next layer begins printing.