BCN3D Sigma R19 – working with CURA software

CURA is one of the most popular programs dedicated to FDM / FFF 3D printers in the world. It is developed and made available under an open-source license by the Dutch Ultimaker, who took over the program and the team that developed it almost 9 years ago, at the very beginning of its activity. Although for some time CURA has been developed primarily in terms of the manufacturer’s own products, it still makes software available to other companies that can customize them to their own needs.

One of the wide range of these manufacturers is the Spanish BCN3D, which offers 3D printers using the system of two independent IDEX printheads. At the moment, there are three models of devices available: Sigma R19, which we have been using for several weeks, Sigmax R19 with an enlarged work area and Epsilon dedicated to work in an industrial environment, with a closed work chamber and the highest work area among all three.

The software is downloaded from the BCN3D website – it is available in versions for all three operating systems in the 64bit version: MS Windows (from Vista upwards), Mac OS (from 10.11 upwards) and Linux / Ubuntu (from 14.04 upwards). There are no demanding hardware requirements – officially all you need is an Intel Core 2 or AMD Athlon 64 processor and 4GB of RAM, however, I know from experience that 8GB guarantees easier and faster work, especially when cutting into layers of large or very complex details. The program needs 205 MB of free hard disk space.

After installation and start-up, choose which 3D printer we want to work with? In our case it was the Sigma R19 model, which we choose from the list of available devices. You can always find 3D printers in the top menu, in the SETTINGS tab – click PRINTER and Add Printer, or in the drop-down bar in the upper right corner.

The software consists of three sections:

• a bar on the left with tools for positioning the model on the table and its simple modifications (e.g. zooming or rotating in XYZ axes)
• the main screen, where the 3D printer work table is displayed and the models that we will print on
• section on the left, where we will find tools for setting individual parameters of 3D printing – starting with the selection of the filament, through the management of the heads, to setting the whole mass of advanced parameters.

We open files for 3D printing either with the first icon in the left toolbar or with the CTRL + O shortcut. CURA opens all major formats for 3D printing: .STL, .3MF and .OBJ. By default, it is not possible to open native CAD-class files (Autodesk Inventor, Solidworks, Solid Edge, Blender etc.) – you need a dedicated plugin, which you install from the Plugins menu, from the top bar. Let us remember, however, that CURA has certain limitations and the export of assembly models does not always have to succeed as we would expect.

The program also allows us to upload GCode files – i.e. cut 3D models ready for printing (a useful function when we generated several files with similar names and got lost what is under which or what settings we used in a given variant?). You can also open graphic files (.JPG, .PNG, .GIF etc.) that are immediately transformed into a simple spatial model. An interesting function, but it significantly limits work – such projects are better prepared on a dedicated program – for example on Windows 3D Builder.

When we upload the 3D model and highlight it, the tools on the left bar will activate. We have at our disposal in turn:

• moving the model on the table
• modification of its size in XYZ axes (checkboxes indicate if the changes are to be symmetrical or whether we will change the detail only in one of the axes)
• axis rotation
• mirror images
• different settings for individual models (inactive).

At the very bottom there are two circles with numbers (1) and (2) – they correspond to the printheads. In the left section, we choose the filament which will be / will be applied to them (this is described below) and assign a head with a filament to a given model. If we duplicate our little Yoda and select a different color for the middle one – it will look like this:

We go to the main screen. When you right-click on the model, an additional menu will open:

Most often we will use the option of copying / multiplying models (also available after CTRL + M). Please note that in the copy window enter the number of copies, not the total number of models. Two useful things that many people do not know or forget – the table view is changed with the mouse and the right mouse button. To move the camera around the table we have to press SHIFT. In turn, when we rotate models relative to the axis, by default they rotate every 15°. By pressing CTRL you can rotate the models every 1°.

The right section consists of three sections:

• upper where we choose filaments and heads (we can also change the 3D printer)
• middle where we set 3D printing parameters
• bottom, where we will find information about the print after cutting it (total working time of the 3D printer and filament consumption).

The first section is quite obvious – from the drop-down lists we can choose which filament to use. We have three options to choose from:

• generic – filaments of external suppliers
• BCN3D Filaments – manufacturer’s filaments
• colorFabb – selected colorFabb filaments (metallic, wood and special engineering).

The materials are divided into specific groups (ABS, PLA, PETG, nylon, etc.) – additionally, when we choose some BCN3D and colorFabb material, the model will change color. Of course, this is not the same color as on the spool – it is only to simulate it.

The principle is the same as for all manufacturers: using dedicated filaments, the user does not have to set any print parameters themselves – they are already adjusted by the manufacturer. By choosing the “generic” option, there is generally no such necessity – unless it appears … And it will appear when the printout does not meet expectations.

Thus, we go to the most important section of the program – 3D print parameter settings. The section is divided into two tabs: Recommended and Custom. In the first case, we choose only the most basic parameters:

• profile – three are available:
  • High quality – very accurate (and long!) On a 0.1 mm layer
  • Standard quality – on a layer of 0.15 mm
  • Draft – fast and not very aesthetic on a 0.2 mm layer
• 3D printing mode:
  • Regular – ordinary
  • Mirror – mirroring (described here)
  • Duplication – copy mode (described here)
• infill – range from 0% to 100%; 20% is set by default
  • the “Enable gradual” option turns on the interesting mode, where models are minimally filled (2-5%), while the closer to closing the upper layers, the filling automatically increases, not allowing holes to appear on its surface, caused by low filling
• Generate support – enables generating support structures
• Support extruder – choose which head the supports will be printed from; if we put water-soluble material – PVA on one of them, we must remember to choose the right head
• Build plate adhesion – we enable printing of an additional substrate for the model (raft, brim etc.).

Switching to Custom mode opens up a whole new range of possibilities. CURA allows you to configure virtually any parameter – for example, there are 28 possible settings just for infill of the model. The vast majority of them concern really small nuances, but their range is gigantic. By default, the user sees only a small part of these parameters – when you click on the gear wheel on the beam a window will open in which you can set the visibility of each of them.

When all the parameters are set, click the “Prepare” button in the bottom right corner. The program starts cutting the model according to our settings and after a short or long time returns the result to us. For example, our Small Yoda measuring 7 x 8 x 10 cm, in High quality mode on a 0.1 mm layer, 20% filling, printed with PLA BCN3D will print for 18 hours and 46 minutes. We will use 83 grams of filament for this. When we switch to the print preview view option on the main screen, CURA will show us how it generated the support.

When we launch a second head to generate supports, we load the water-soluble PVA into the working time will be significantly longer – it will take 1 day, 14 hours and 43 minutes. In addition to the model, the 3D printer will print an auxiliary tower, with the help of which it will prepare heads and materials for printing, before applying the next layer.

The above settings are the default. We can modify them to a large extent using custom settings. Theoretically, with the right approach, the above model can be printed just as correctly, but with much less filament consumption and in a shorter time.

If we decide that the model is suitable for 3D printing, click “Save to file”, which appears in the “Prepare” place. The work with CURA is finished and we can work witch our Sigma R19 again…