The Sigma has two hot ends each on their own carriage which eliminates most of these challenges. Calibration becomes much easier and the opportunity to ooze material from the inactive nozzle is completely eliminated.
This feature is called the IDEX System.
Large touchpad control screenSigma is outfitted with a large built in touchpad and an SD card reader. This allows for easy printing without being connected to a computer and also allows for some nice visual cues for the calibration process.
Optimized Calibration Process
Setting up your printer so that the first layer sticks properly can be tricky especially for new users. Many printers are starting to incorporate z-axis compensation, also referred to as auto-leveling, where the printer probes several points on the bed to define how to adjust the axis to print. The problem with this is that it moves the z-axis up and down within a layer. For a cartesian style printer, you do not want the z-axis moving within a layer as it can introduce movement related quality defects (and who wants another source of defects in a 3D Printer?) .
The BCN Sigma uses a really cool process where each head probes the bed at several locations and provides a simple easy to read visual indication on the touchpad for you to adjust a certain number of notches on a dial under the bed.
It then prints a pattern. You simply pick the best pattern to align the heads and enter it into the touchpad just like you do with a high quality color paper printer. Easy.
Bigger and more complex pieces and a Removable build plate
The printing volume is 210x297x210mm (~8.25x11.7x8.25in) will allow you to print some pretty sizable objects in a single print.
In addition, the flat glass printing bed is magnetically attached in a no-interference mounting scheme that allows for the bed to be removed when you change prints and replaced without requiring recalibration.
BCN3D Sigma works with the BCN3DNozzle v3, a fully metallic Hotend capable of operating at high temperatures up to 280ºC. Its standard nozzle is 0.4 mm and it can work at a minimum layer high of 50 µm. It can be fitted with available larger diameter nozzles for printing of specialty materials and faster print completion times or smaller nozzles for higher detail.