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3D Printing

Guide to support students using 3D printers in the Innovation Lab

Importing Files into Cura

There are three quick ways to load your file:

  •  Click on "File" and "Open File(s)" and select your file from the location it is saved. This feature can open model and project files.
  • Use the in-program "Open File" icon to add models to the build plate.
  • If Cura software is already open and you have your .stl (from desktop or other local file location), you can click and drag the .stl file onto the virtual build plate.

Basic Overview to Print in Cura

The image below is of the background of the corresponding computer station for our Ultimakers. You will see it has an image of each machine this computer is able to print to as well as the program icons below to indicate what programs to use. Use this background image to help determine if you are at the right machine or not. The RED boxes on the image indicate the program icons that you can click to start the program(s).

 

For Ultimaker 3D printers you will use the Cura windows pictured below. These windows are prepared at the beginning of the day to provide a consistent experience and understanding of which window to use. If you do not see the windows, please look to the taskbar since they may be minimized by other users. DO NOT CLOSE THESE WINDOWS!!

 

ONLY IF YOU CANNOT FIND THESE WINDOWS, then double-click the "Cura" icon to start the Cura software.

 

After your model has loaded into the 3D plane (see above section,"Importing Files into Cura" for loading a model), the left toolbar icons for Move, Rotate, Scale and Mirror will appear. They will be greyed out until you select the model on the virtual build plate. Use the "Print Settings" panel to adjust settings. Common default settings are .15 mm line height (resolution), 20% infill, support "checked" and adhesion "checked". Adjust these settings as your model requires.

 

When you are ready to print you can click the "Save to Removable Drive" button in the lower right. Making sure Ultimaker printer you intend to use is not printing, remove the USB drive and plug into the appropriate workstation to reveal the "Save to Removable Drive" option. If you are wanting to save your project so you can print it another time, go to File -> Save project -> which will show a dialog box of the settings of your project. Click "Save" and in the following "Save to File" dialog box navigate to where you would like to save your file. When you are ready to print, open this file and the model/settings you saved will be loaded into Cura.

Basic Overview - Video

Left Toolbar Instructions

Adjusting the model

Cura offers several tools to adjust the model before printing. This allows you to easily position models on the build plate in the most efficient way. Below all the adjustment tools are described.

Move tool

Selecting the model (3) automatically opens the move tool (1). The coördinate system (2) can be used to set the specific place of the models. Three arrow handles (4) appear connected to the center of the model, one arrow for each axis.

  • The object can be moved freely by ‘click-and-drag’ anywhere on the object (3).
  • Clicking one of the arrow heads (4) allows the model to be moved on one axis at a time.
  • Note: Removing bottom of object is done by setting a negative Z-value in the coordinate system(2).

 

 

  1. Move
  2. Coordinate system
  3. Model, click-and-drag move
  4. Arrow handles, move per axis

 

Scale tool

Select the scale tool (1) to bring up three handles and a tool panel. The model can be scaled on three different ways:

  • Drag one of the handles (4) to scale the object.
  • Use the ‘shift’ key on the keyboard to disable snap scaling (6).
  • Use the ‘control/command’ key on the keyboard to enable uniform scaling (7).
  • Set a specific dimension in the tool panel (2), for the X,Y or Z axis.
  • Set a scale percentage in the tool panel (3), for the X,Y or Z axis.
  • Reset the object to its original dimensions (5).

 

 

  1. Scale tool
  2. Object dimensions in millimeter
  3. Object scale as a percentage
  4. Scale tool handle
  5. Snap scaling
  6. Reset the object to its original scale
  7. Uniform scaling

 

Rotate tool

Select the rotate tool (1) to bring up a tool panel and three rings around the object, one for every axis. The model can be rotated in the following ways:

  • Drag one of the rings (4) along the axis. While dragging, the rotate angle (5) is displayed next to the mouse pointer.
  • Use the ‘shift’ key on the keyboard to disable snap rotating (6).
  • Reset the object rotations (2) back to the original state.
  • Lay the object flat (3) on the build plate. (Rotate the object close to this position for the tool to always work correctly.)

 

 

  1. Rotate tool
  2. Reset
  3. Lay flat
  4. Rotate rings
  5. Rotate angle
  6. Snap rotation

 

Mirror tool

Select the mirror tool (1) to bring up a tool panel and six arrowheads, two for every axis. To mirror the model:

  • Click one of the arrowheads (2) of the desired direction.

 

 

  1. Mirror tool
  2. Mirror arrowheads

 

Per model settings *Only available on dual extrusion machines

With this tool it's possible to adjust settings per model.

Select ‘per model settings’ (1) to bring up a tool panel. The model in the 3D viewer (3) gets highlighted to show which object is being adjusted.

  • Add a custom setting to the object by clicking select settings (10).
  • Choose the extruder to print this model with (3).
  • Select the custom setting in the settings panel (7).
  • Change the value of the setting or remove it with the '-' button (9).

 

 

  1. Per model settings
  2. Normal model
  3. Model
  4. Setting filter
  5. Show all
  6. Close
  7. Active setting
  8. Remove setting
  9. Setting values
  10. Select settings

Left Toolbar - Video

Right Panel Instructions

Below you will see screen shots of the settings you can adjust to refine your model print as needed. These settings have default values that can be obtained by clicking the counter-clockwise arrow next to the field value.

Fields below that should generally not be adjusted are:

Material - Diameter, Flow, Enable Retraction
Speed - Travel Speed, Print Acceleration, Travel Acceleration, Print Jerk, Travel Jerk
Build Plate Adhesion - Initial Layer Z Overlap
 

 

These categories of adjustments are explained in further detail below.

Quality

 

Layer height

The layer height - one of the most often changed settings - is the thickness of one printed layer (in mm). With a thinner layer height you will increase the quality of the print, leading to a smoother surface and more detail visible in the Z-direction (height) of the model. On the other hand, by using thicker layers you can decrease the print time substantially.

There are 3 typical settings for indication:

  • 0.06 mm: A high resolution, at which the layers are barely visible.
  • 0.1 mm: Used for most prints. The golden mean between a fast print and good quality.
  • 0.15 - 0.2 mm: Used for fast prints. At this speed the layers still create an overall usable part while minimizing the print time.

Read More on Quality Settings in Cura


Shell

 

Wall thickness

This setting adjusts the thickness of walls of the model. Cura will approach the value set here as much as possible by calculating how many walls should be printer with the given nozzle. A value of 1mm, results in 3 walls of 0,35mm = 1,05mm wall.

In general a wall thickness of 2 or 3 times the line width is sufficient. A higher value will create a sturdier model and decreases the chance of leaks, while a lower value can significantly decrease the print time and filament costs.

Wall Line Count
Instead of setting a thickness in millimeter of the walls, you can also set a number of walls. When you set the wall line count, the wall thickness is calculated and will grey out.

Read More on Shell settings in Cura


Infill

 

Infill density

The infill density defines the amount of plastic used on the inside of the print. A higher infill density means that there is more plastic on the inside of your print, leading to a stronger object. An infill density around 20% is used for models with a visual purpose, higher densities can be used for end-use parts.

Infill line distance

Instead of setting the infill density as a percentage, it’s also possible to set the line distance. This determines the distance between each infill line, which has the same effect as changing the infill density.

Read More on Infill settings in Cura


Material

 

Default printing temperature

This is the printing temperature of the materials as found in the materials panel, without any corrections applied to it.

Printing temperature

This is the temperature of the nozzle that is used during printing, calculated by the flow of the material. Each printing profile has a slightly different printing temperature to create the best print result.

Printing temperature initial layer

This is the printing temperature of the layer that adheres to the build plate. Printing slightly warmer increases the adhesion between the build plate and the model.

Initial printing temperature

This setting is only used in dual extrusion machines. When switching nozzles, the inactive nozzle cools down to the standby temperature. During the warm up, the nozzle is allowed to start printing when this temperature is reached. The temperature is slightly lower than the printing temperature since the filament already obtained heat from the nozzle for a longer period of time.

Read More on Material settings in Cura


Speed

 

Print speed

The print speed defines at which speed (in mm/s) the print head moves while printing. Based on this setting, Cura will also calculate how fast the filament must be extruded. A higher print speed will lead to a shorter print time. But keep in mind that increasing the print speed means that you might have to increase the temperature as well, to ensure the plastic is properly melted.

Although you can choose one overall print speed for the complete print, it’s also possible to use different print speeds for specific parts of the print:

  • Infill speed: The speed at which the infill material is printed. Since (visual) quality of the infill is not important, you could use a higher speed for the infill. But keep in mind that this might affect the strength of your print.
  • Outer wall speed: The speed at which the outer walls are printed. Printing the outer wall a bit slower usually results in a better surface finish.
  • Inner wall speed: The speed at which the inner walls are printed.
  • Top/bottom speed: The speed at which the top and bottom layers are printed. A lower speed increases the reliability of closure of the top layers, especially on large area prints.
  • Support infill speed: The speed at which support structures are printed. The quality of the support is usually not that important, so a higher value can often be used here.
  • Support interface speed: The speed at which support roofs and bottoms are printed. Since these need to adhere to the model properly, they are printed quite slow.

Read More on Speed settings in Cura


Cooling

 

Enable cooling fans

With this setting you can enable or disable the print head fans during printing. The print head fans will make sure that the material is properly cooled before the next layer is placed on top of it. Especially on layers with a short layer time and layers with bridges/overhangs, cooling will increase the print quality.

Read More on Cooling settings in Cura


Support

 

Generate Support

Some models have overhanging parts, which means that parts of the model float mid-air when you would print the model. In this case, you must print a support structure under the model to prevent the plastic from falling down. This can be achieved by enabling generate support.

Support extruder

Dual extrusion machines provide the possibility to create water soluble supports. To make use of that feature, you can specify which parts of the support are printed with wich extruder. The setting is split up in:

  • Support infill extruder
  • First layer support extruder
  • Support interface extruder
  • Support roof extruder
  • Support floor extruder

 

Placement

This setting defines where the support structure is printed. It has the following options:

  • Touching build plate: Support material is only printed from the build plate up.
  • Everywhere: Support material is printed below every part that needs support, which means that it can also be placed on or inside a model.

 

support, placement, chair
This model of a chair has support touching build plate on the left and support everywhere on the right.

Overhang angle

The overhang angle is the maximum angle of overhangs for which support material is added. A smaller angle leads to more support. This means that at a value of 0° all overhangs are supported, while at 90° no support material is added.

Support_angle

The model on the left has a support angle of 50°, the model on the right 70°.

Read More on Support settings in Cura


Platform adhesion

 

Enable prime blob

This setting is for dual extrusion machines only. The printer normally starts with a blob of material, to prime the nozzle. Disable this setting to use the skirt or brim to prime the nozzle instead.

Build plate adhesion extruder

This setting determines which extruder prints the selected build plate adhesion. This setting is only available in dual extrusion machines.

Brim

Brim adds a single layer flat area around the base of the model to prevent warping. The brim is connected to the model and will thus make the bottom surface area bigger. This means that it can better stick to the build plate and in case of warping the corners of the model are less likely to curl up because of the brim attached to it.

Especially materials that have a high shrinkage (e.g. ABS) can benefit from using a brim. But also models that either have a very big base or very thin parts at the bottom will stick better to the build plate with a brim.

There are multiple options available for the brim setting:

  • Brim minimum length: The length in millimeters here is the amount of filament that is extruded, no matter the other brim settings.
  • Brim width: This setting adjusts the width of the brim in millimeters.
  • Brm line count: This setting overrides the 'brim width', setting the width by the number of printed lines.
  • Brim only on outside: This setting ensure that models with holes on the initial layer, like a donut shape, only have brim on the outside of the model.

 

Raft

A raft adds a thick grid with a roof between the model and the build plate. This can especially be useful when the bottom surface of a model is not completely flat or has little adhesion to the build plate. With a raft you make sure that the model will stick better to the build plate in this case.

The raft options in Cura are quite overwhelming, since the raft is divided into 3 parts: Top layers, middle layer and base layer. The image below tries to visualize all the possible raft settings available. The following information is important to know in advance:

  • Initial Z overlap: This setting lowers all layers of the model except the initial layer, to press the initial layer against the raft.
  • Raft base layer: This layer is meant to be pressed against the build plate, therefor it looks oversized.

Skirt

A skirt is a line printed around the object on the first layer, but not connected to the object. This helps priming the extrusion and can also be a good check for bed leveling before the print starts.

If you select skirt, you can adjust the following parameters:

  • Skirt line count: The number of skirt lines printed around the model.
  • Skirt distance: The distance between the model and the skirt.
  • Skirt minimum length: The total length of the skirt. This will override the skirt line count when the minimum length is not reached yet.

Right Panel - Video

Dual Print - Video

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