So, you have a 3D model in the STL or OBJ file format – either from a platform such as Thingiverse or one you designed in a software application such as FreeCAD or SketchUp. What next?
Before you can have your 3D model output on your 3D printer, the model has to be translated into a format that the printer can handle. This process is called slicing as the model is divided into small layers – the slices.
You need a special software to do the slicing. In this tutorial, we use Cura, the free software created by the makers of the Ultimaker printers. Cura allows you to import a STL (or OBJ) file and prepare it for your printer model (each model has its specific settings).
In Cura, you set a number of settings that depend on your printer, on your model and the print material used. The most important settings are layer height and layer thickness. Next, Cura calculates the outline of your model layer by layer and determines the path the print head has to take in order to print your object.
Cura not only slices your model: It creates the commands your printer interprets and executes while printing. This code is called the G-code. When Cura is finished, you save this code to a file on a SD card that you feed into your printer.
Cura Tutorial – Lesson 1: The Basics
In lesson 1 of this Cura tutorial for 3D printing beginners, you’ll learn the basic steps needed to turn a 3D model in STL or OBJ format into a file your 3D printer can use, a G-code file.
Cura Tutorial – Basics – Step 1: Installing Cura 3D
1. Get the installation file for your operating system from the Ultimaker website and install the latest version of the software. In this tutorial we use Cura 15.04 (dating from November).
2. Launch Cura.
3. Select your printer model.
Cura Tutorial – Basics – Step 2: Quick overview
This screenshot shows the basic features:
1 Open file: Use this button or the File > Open command to open your STL or OBJ file.
2 View Mode: This button lets you switch between Layers and Solid view.
3 Print Setup: From here, you open the printer-specific settings.
4 Mode: In Simple mode only very basic settings can be changed, in Advanced mode you have access to all printer settings. We’ll start in Simple mode and switch to Advanced mode in lesson 2.
5 Save to Disk: When you’re finished, save the G-code to your hard disk or SD card for the printer.
Cura Tutorial – Basics – Step 3: Handling your model in Cura
1. So, now load a 3D model into Cura using the Open button or the File > Open command.
Hint: For this Cura tutorial we use a STL file you can download for any web for 3D design. It is a simple adjustable clip-on stand for a tablet.
2. Now explore the two views: Solid view and Layer view. In Solid view, you see the entire object the way it will look when printed. In Layer view, there is a scrollbar to the right through which you select an individual layer; alternatively, you can go through layer by layer using the Up/Down arrow keys on your keyboard.
When switching to Layer view, it may take a while before the layers are calculated and displayed (depending on the model and on your computer hardware).
When switching to Layer view, it may take a while before the layers are calculated and displayed (depending on the model and on your computer hardware).
3. After loading your model, you can scale, rotate or mirror it on the build platform using the three buttons to the left. Just play with these three functions (you can undo the changes later).
Hint: We recommend, you switch to Solid view before rotating the model as it takes a while to recalculate the layers in Layer view so you may find rotating to be quite sluggish.
4. When you select the model, a green and a red arrow appear. Using these arrows, you can move the model to the front/back and left/right on the workspace.
5. When you wish to see more details, click the Scale button and enter a higher percent value – keep the Uniform Scaling setting, otherwise the printed model will be distorted. To close the Scale dialog box, click theScale button a second time.
6. Right-click the model to open the context menu. From here, you can undo the changes to the model and center it on the platform again.
You may also duplicate the object, if you wish to print several copies of the model.
You may also duplicate the object, if you wish to print several copies of the model.
Cura Tutorial – Basics – Step 4: Cura settings
For now, we work in Simple mode. Here, there are only two setting available: You may select print quality and you may have support structures printed together with the model:
1. Check the Enable Support option (in our case, no supports are needed). But most 3D models require support structures. So it’s best to always have Enable Support checked.
Supports are needed when your model has overhanging parts or parts floating in the air.
Supports are needed when your model has overhanging parts or parts floating in the air.
2. Use the slider to set the print quality. Cura displays the print duration for minimum and maximum print quality. The field above the Save to Disk button displays estimated print time and material required for the currently selected quality.
For a quick print of a draft, pull the slider to the left. If you need maximum quality and time is not as important as quality, move the slider to the right – to Maximum Quality.
For a quick print of a draft, pull the slider to the left. If you need maximum quality and time is not as important as quality, move the slider to the right – to Maximum Quality.
Cura now calculates layer height, print speed and other settings according to the quality you selected.
And: Cura remembers these two settings and defaults to them when you open a new model.
Cura Tutorial – Basics – Step 5: Generate a G-code file
For this first lesson we are almost finished. The last step is saving the model in a printable gcode file.
1. Click the Save to Disk button or select File > Save.
2. Enter a file name and the folder where the file is stored. You may store the file on the SD card you use to transfer the file to your 3D printer; we usually first store the file on the hard disk and then copy it to the SD card.
3. Select GCode File (*.gcode) and click Save.
4. Copy the file on a SD card and insert that in your 3D printer’s SD slot.
Cura Tutorial – Lesson 2: Cura Settings
In lesson 2 of this Cura tutorial for 3D printing beginners, you’ll learn how to finetune the Cura settings: quality, material, speed, cooling, support & platform adhesion.
While the basic print settings are fine to start with, the Advanced Cura settings give you more control over the output. Basically, there are two ways to access the Advanced settings:
1. through the tabs in the Print Setup pane on the right-hand side of the Cura window,
2. through the Preferences > Machine settings.
The Print Setup pane contains the most important settings, while in thePreference > Machine dialog you have access to all the print settings – and you can select to have some of these settings displayed on the Print Setup pane, too.
Let’s start with the Print Setup pane.
Cura Tutorial – Settings – Step 1: Quality settings
1. In the Mode field, select Advanced instead of Simple. Below Print Setup, a number of tabs for Quality, Material etc. settings are displayed.
2. Click Quality to define the surface quality of your 3D printed object.
3. Layer Height is by default 0.1 mm. If your printer supports thinner layers, you decrease the height to get smoother surfaces – that will increase print time, however.
4. The Shell Thickness setting of Cura determines the thickness of the walls of the object. It has to be an integer multiple (1x, 2x, 3x, etc.) of the nozzle diameter. A thickness setting of 0.8 mm means that walls will be 2 lines wide (as the nozzle of our Ultimaker 2 printer has a diameter of 0.4 mm).
5. The Bottom/Top Pattern can be either Lines or Concentric.
6. The Bottom/Top Thickness is usually also set to 0.8 mm. If you print an object with a large flat top, you may want to print more layers in order to close the top surface completely. This avoids the unwanted „pillowing“ effect. As the Bottom/Top Thickness setting is not by default in the Print Setup pane, you first have to open Preferences > Machine and check Bottom/Top Thickness – now the setting will be displayed in the Print Setup, so you can increase the value (again in integer multiples of the nozzle diameter)..
Cura Tutorial – Settings – Step 2: Material settings
1. Usually, there is only the Retraction option in the Material section. We recommend that you leave Retraction turned on. Retraction means that the filament will be retracted, i.e., pulled back, when the printer nozzles moves over an area that is not printed. This way, no filament will come out of the nozzle. There will be no „stringing“ – no thin threads of plastic between the printed parts of your object.
2. If you wish to change other material settings, open Preferences > Machine and check the settings you need to change. When you use a Ultimaker Original or Original+ you need to set the correct Printing Temperature and Bed Temperature (if you have a heated print bed). For the Ultimaker 2 series, you set the temperatures through material profiles in the printer itself (not in Cura).
The recommend temperature settings for PLA are a Printing Temperature of 210 Infill Thickness C and a BedTemperature of 60°C; for ABS set the Printing Temperature to 250°C and the Bed Temperature to 90°C.
The recommend temperature settings for PLA are a Printing Temperature of 210 Infill Thickness C and a BedTemperature of 60°C; for ABS set the Printing Temperature to 250°C and the Bed Temperature to 90°C.
3. Usually, there is no need to change the default Diameter and Flow values. If you have to do so, enable the settings underPreferences > Machine.
Original Ultimaker filaments have a diameter of 2.85 mm. If you use filament from other providers, the diameter may differ. Measure the diameter using a caliper and enter the value in the Diameter option.
Flow is the entire amount of material that needs to be extruded for your object. The Flow value is usually set to 100%, so the extruded amount equals the amount of material required. You only need to increase this setting if you use very soft materials.
Original Ultimaker filaments have a diameter of 2.85 mm. If you use filament from other providers, the diameter may differ. Measure the diameter using a caliper and enter the value in the Diameter option.
Flow is the entire amount of material that needs to be extruded for your object. The Flow value is usually set to 100%, so the extruded amount equals the amount of material required. You only need to increase this setting if you use very soft materials.
Cura Tutorial – Settings – Step 3: Speed settings
1. If you wish to print faster than the default (and recommended) 50 mm/s, you may increase the value Print Speed. In this case, we recommend you also increase the Print Temperature value so that the plastic is properly melted.
2. The Travel Speed setting determines how fast the print head moves when it is not printing (e.g., when moving from one wall to the next). The default 150 mm/s is fine for most cases.
3. In the Preferences > Machine dialog, there are other speed settings that let you control the speed for specific parts of the print. In case, you wish to change any of these speed settings, set them to integer multiples of Print Speed – this makes accelerating and decelerating smoother when changing e.g. from infill to shell printing.
Cura Tutorial – Settings – Step 4: Infill settings
1. Infill Density determines how much plastic is printed inside the object. A higher value means that more plastic will be printed – which will result in a stronger object. Typically, 10% to 20% are sufficient to build strong objects. In case, you wish to print the object completely hollow, set the density to 0%.
2. If you wish to change other infill settings, first select them in thePreferences > Machine dialog to make them accessible on the Print Setup pane. The Infill Thickness and Infill Layers settings (which are new in Cura 15.06) allows you to reduce print time when the quality of the infill is less important: sparse infill is printed in fewer layers to save print time. Infill Thickness sets the thickness of the sparse infill; the value has to be a multiple of the layer height. Infill Layers allows you to combine several layers to form sparse infill.
Cura Tutorial – Settings – Step 5: Cooling
1. Turning of the Enable Cooling Fan setting is not recommended as it will result in warping and other ugly surface effects.
2. In order to control the cooling fan more precisely, enable the Cooling settings in the Preferences > Machine dialog, e.g. the Fan Speed settings in order to increase Maximum Fan Speed when it is very hot in the office or to decrease it when the fan is too loud.
3. When you want to make sure a layer has enough time to cool before the next layer is printed above it, set the Minimal Layer Time. Increasing this value also increases print time.
4. Through the Minimum Speed setting you can make sure the printer does not slow down too much as that means that the nozzle will be on the same spot for a longer time – keeping the plastic at that spot hot. A Minimum Speed below 100 mm/s will reduce print quality.
5. When you print an object with a small top, we recommend you use the Lift Head option. This removes the print head from your object so it can cool down (otherwise, you may end up with a blob at the top of the object).
Cura Tutorial – Settings – Step 6: Support settings
1. Do not turn the Enable Support option off – otherwise floating or overhanging parts cannot be printed.
2. The Placement option determines where supports are attached:Touching Buildplate means the supports are based only on the build plate; Everywhere means the support structures can also be built on the model or inside the model.
3. The Overhang Angle value determines how much overhang a part has to have to be supported; the default is 60°. Note that setting the Overhang Angle to 90° will create no support structures at all.
4. New in Cura 15.06 is the Use towers setting. These „towers“ are special support structures that have a larger diameter than the supported parts and that are smaller at the top. This way, these supports can be removed more easily, there will be less traces of the supports on the printed object.
Cura Tutorial – Settings – Step 7: Platform Adhesion settings
In order to improve bed adhesion or in case your object does not have a flat bottom, you can add a brim or a raft. If you don’t, Cura automatically adds a skirt around the object. The skirt is a line around the print on the first layer that helps prime the extruder. A brim is made of a few lines attached directly to the object’s bottom; this increases the bottom surface and minimizes warping. A raft is a thick grid underneath the model and helps the object stick to the build plate.
* In case, you simply want the skirt printed, set Type to None and select the number of skirt lines and the distance to the object.
* If you want a brim printed, select Type: Brim and set the Brim Line Count, i.e., the number of lines to be printed.
* To have a raft printed, select Type: Raft and adjust the margin, the thickness and other settings.
We hope you enjoyed reading this Cura tutorial.
License: The text of "Cura Tutorial for 3D Printing Beginners" by All3DPis licensed under a Creative Commons Attribution 4.0 International License.
