BCN3D Sigma Review 2017: A Fantastic 3D Printer

Last updated, May, 2017

Although Dual extrusion 3D printers are capable of printing different materials and colors, most 3D printing enthusiasts shy away from them. Their reputation has mostly been ruined by claims that they are extremely complicated to use.

The BCN3D Sigma therefore took the world of 3D printing by shock when it quickly escalated to the very top of the list on the best 3D printers. Its fast popularity resulted from its ease of use, which seems to have been its main focus.

Our curiosity was sparked not by the fast rise in popularity of the Sigma printer, but by the fact that  it has managed to be on the top of the list for 3 months now…without much competition.

Overview of the BCN3D Sigma Printer

This BCN3D printer was designed and manufactured in Barcelona, Spain. It’s 100% open source. This means all the hardware, software, and supporting documentation is hackable, tweakable, and can be modified under the terms of a General Public License. This is an attractive aspect of this printer, and makes it stand out from other printers in the market.

What this BCN3D Sigma Review will cover

  • A brief history of BCN3D Sigma
  • Design, Features and Specifications of the BCN3D Sigma
  • Assembling the BCN3D Sigma
  • Reviewing the BCN3D Sigma Software
  • Filament and the BCN3D Sigma
  • Printing with the BCN3D Sigma
  • Merits of the BCN3D Sigma
  • Demerits of the BCN3D Sigma
  • Addressing Concerns
  • Verdict

History of BCN3D Sigma Printer

BCN3D Technologies is not an actual company but a special division of Fundació CIM, a non-profit educational foundation of the University Polytechnic of Catalonia. Because of this, the group is deeply rooted in the RepRap movement. This group has been researching and exploring the possibilities of additive manufacturing for more than two decades. It has also been sharing its experiences and milestones achieved with the 3D community as a way of promoting and commitment to open source.

The group’s desktop 3D printing blue-chip were DIY kits like the BCN3D+. The chips are structured in an easy way such that they can be assembled at home. After creating the chip, the group decided to follow the trial and error approach. This resulted in development of the Independent Dual Extrusion (IDEX)

The IDEX system uses a different methodology in operation. It separates the hotends and extruders such that each print-head can operate independently from the other. This is unlike the usual way of mounting two extruders and hotends, which is popular with most dual extrusion machines. This unique approach of IDEX enables the machine to undertake single extrusion jobs. Genius, huh?

bcd3d printer dual extruders

The BCN3D Sigma printer can also impressively print complicated two-tone models on the very first attempt. The printer is reliable and the quality of the prints is just unrealistic! (Pun intended). When we tested the IDEX, we were mesmerized with almost every single bit of it.

Design, Features and Specifications of the BCN3D Sigma

This cutting edge machine measures 465mm x 440mm x 680mm, is aluminum-framed and power-coated. The printer has an exclusive design. Its angles are sharp, the front and top are open, and its semi-open frame has sweeping curves. Both its sides have transparent plastic inserts.

Among the 3D printers that we’ve tested, the BCN3D printer’s build area is one of the biggest, following the E3D Bigbox and the Ultimaker 2 Extended. The BCN3D measures 210mm x 297mm x 210mm. The printer has a resolution ranging from 300 microns down to 50 microns (a micron is 0.001mm).

The Printbed of this machine is made of glass, overlaid on top of a PCB heatbed. There are magnets that hold the glass in position. Both the Printbed and the IDEX assembly are constructed on movable motorized carriages. Whereas the two extruders move on the y and z (horizontal) axes, the print bed moves on the x axis (vertical).

The Printbed is easy to maintain and  clean due because it’s held by strong magnets. The magnets are designed with cut-outs on the angle that sit flush with the heat bed. This makes them resistant to heat and also keeps them from weakening with time.

The BCN3D Sigma printer is also designed with an SD card slot. Unfortunately, it lacks wireless connectivity. Instead, a color touchscreen display is used for managing the machine. This touchscreen is averagely responsive, except for some little wobbly to the touch.

The machine is bulkier due to the positioning of the filament inside it. Each of the spools sits on the side of the machine, in a lower recess shelf. However, you will be feeding the filament under, behind and from the bottom of the printer until you see it peeping from the top in a sweeping curve through the guiding tube and into either of the two print heads. When you look at the filament from the front, what you will see resembles a grasshopper on steroids.

What might worry you is what to do should the filament breaks. However, we haven’t experienced this yet.

Read more about the design evolution of the BCN3D Sigma here.

design evolution of the bcn3d sigma printer

Assembling the BCN3D Sigma

The BCN3D Sigma is not an overly complicated machine. In fact, setting it up is rather easy. Moreover, there is a fully illustrated quick-start guide to help you out. The guide is available in both Spanish and English. There is also online support material with more elaborate documentation, if you need more support.

When your BCN3D Sigma package arrives, lift the printer from the box and remove the available packing foam and security tapes. In the package, you will also find the instruction sheet, cables, a box of tools and a can of adhesive spray for the print bed. With these, you’re set for to begin set-up.

Setting Up the Printer

There are roughly six steps to follow when setting up the printer.

  1. Pop in the glass bed
  2. Add the two filament spools and insert the ends to the feeding unit
  3. Attach the guide tubes for each filament and clip them to the hotend cables
  4. Insert the “cleaning rubbers” for the hotends
  5. Slot in the SD card and the power cable
  6. Load the filament and start calibration

Most users get nervous about the calibration stage. However, there is really nothing to be scared of as there’s a step-by-step guide on the touchscreen interface. You will also receive a guide on how to prepare a model for printing using the slicing software on your computer. The BCN3D Sigma printer comes with Cura application. However, you are also free to use any other applications you prefer.

Basically, the time it will take you from unpacking your BCN3D Sigma to doing your first print is about 15 minutes.

bcn3d printer instructions manual

BCN3D Sigma Software Review

There are various 3D printing slicer software that the BCN3D Sigma is compatible with. These include:

The main objective of a slicer is to convert STL file into layers based on your chosen resolution and supports. The slicer further splits the STL file into GCode format for printing.

The slicer software that we chose in our case was the Simplify3D. It was our best option not just due to its ease of use, but also because it has more features. The first thing that appears when you open Simplify3D on your computer is a virtual print bed. There is a menu on the left side of the window where you import your process settings and your model to be able to tinker with the resolution. There are five options available for the print quality; Strong, High, Fast low and medium quality.

There’s an option for specifying the type of filament that you’re using. When you select this, a further list of presets for optimizing the printing process will appear. Here, there is a range of infill styles you can choose from, perhaps because you want to use your filament sparingly or want lightness or stability.

Also, if you want to hold overhang parts of your object in place as printing continues, you can select the option for adding custom supports on any part of the model. Other options are available with this software. These options come handy when you are experiencing difficulties of the print in your first layer sticking to the bed. The options include:

  • A brim
  • A raft
  • A thin extension of plastic around the base of your object to hold it firmer

One thing to note about dual extrusion is that you have 2 STL files intersecting each other. Luckily, Simplify3D has a nifty wizard that groups the models and then aligns them correctly. This makes it easier for you to go through the setup process.

There’s also a fast-forward animation preview that will help you see how printing will be performed. When you’re ready to print, export the file to the included SD card, slot it into the Sigma and select it from the print menu and then wait.

simply3d user interface

Filaments for the BCN3D Sigma

The BCN3D Sigma uses the 2.85mm filament instead of the 1.75mm that is common in FFF (fused filament fabrication) 3D printing. The printer does not restrict its use only to the PLA (polylactic acid) or ABS (acrylonitrile butadiene styrene) materials. Other filament materials that the machine supports include: HIPS, ABS, TPE, ColorFabb co-polyesters, and polyvinyl alcohol (PVA).

bcn3d sigma printer

The Sigma does not limits your imaginations and creativity. Physical things like bridging and overhang, which are usually limited to the scope of designs, are not a bone of contention with this machine.

The secret with dual extrusion printing lies with using the right material and quality of filament. The material we used for our test run was the white PLA and the Colorfila black, which we chose based on other reviews. These materials come in perfect colors and can make two-tone prints for aesthetic purposes. However, if you want a primary material for building your object and a dissolvable secondary material for support, you can pair HIPS with ABS or PVA with PLA.(See pictures below).

pva 3d printer models

Printing with the BCN3D Sigma

We had no trouble printing a number of test objects on the BCN3D. We printed about 5 objects at a “Strong” quality setting (200 microns), then another 5 at “fast low quality setting” (250 microns) and finally 3 at “high quality prints” setting (50 microns). We had no real difficulty printing a majority of these and the outcome was satisfactory. The lower the value of the resolution, the finer the outcome (in resolution), since resolution is a measure of layer height.

However, to ensure the first layer was smoothly executed, we did some initial tweaking on the extrusion multiplier and the temperature. We were happy we did this because we attained phenomenal print quality; especially with the single extrusion.

Our test prints for single extrusion was with a Rook chess piece, a 3DBenchy, and a Marvin mascot. All these were printed at high quality. The outcome was so fine we could literally compare them to selectively laser sintered (SLS) object. If you placed the two side by side and viewed them on low light, you might fail to differentiate them.

3d models printed by bcn3d sigma

So, did we have any disappointment with any of the prints? Yes we did. When we printed a two-tone 3DBenchy using fast-low quality setting on single extrusion, it came out a little lousy in quality compared to its monochrome counterpart.

Our test prints for the dual extrusion was a traffic cone by R3ND3R, a puzzle draudi by BCN3D, and a striped frog by nervous system. The outcome for all of these was explicit on the very first try. However, we had to do some post processing to remove stringing threads from the model that had resulted from constant hopping between the two print-heads.

dual print by sigma bcn3d printer

On the plus side, the surface layering was visibly accurate. We were tempted to switch to a higher quality setting for finer resolutions. However, we feared that the prints would take more time to be completed and we really were not ready to be patient.

quality of the bcn3d printed model

Merits of the BCN3D Sigma

  • Setting up is relatively easy and fast
  • Magnetic build plate
  • The design is attractive and ergonomic
  • The filament feeding system is simple and efficient
  • The printer works with various slicing software including Simplify3D and Cura
  • Automatic calibration probe
  • Open source innovation has come with Independent dual extrusion
  • Quality tools provided
  • Excellent print quality

Demerits of the BCN3D Sigma

  • There are some bugs on the touchscreen interface
  • Lacks wireless connectivity
  • It’s difficult to estimate timings for dual extrusion print jobs
  • Is massive in size, and hence bulky and hard to transport
  • It’s not a very silent printer. However, the noise levels are acceptable
  • The dual extrusion settings tend to lead to a lot of wastage

Addressing Concerns

We performed test projects for both the single and the dual extrusion. With the single extrusion, there were not many issues to be worried about. However there were a few issues with the single extrusion that caused concerns. These include:

When the extruder is not in action, a small amount of filament is still ejected. This causes a big mess even when doing medium sized print as the waste fills the cleaning rubber container fast. The color calibration column that the IDEX creates to maintain printing consistency also contributes to waste. We assume this continuous extrusion, even when not in use, is for maintaining constant flow and temperatures. However, we did not get used to it.

The printer does not display the expected print job completion time on the touchscreen. Instead, a percentage estimate (that’s not very useful) is what’s given. However, comparing this problem with that of Simplify3D, we think that maybe the issue is not with the BCN3D Sigma, but with the slicer software that we used. Although the slicer software we used with the Simplify3D provided an estimated time for completion of the print job (12 hours for one model), it actually took longer(16 hours) for the model to be completed.

The touchscreen interface was not stable and navigating menus was a huge frustration. We experienced a major halt when tweaking the settings in the middle of a print for the dual 3DBenchy. Moreover,there was little we could do when the menu froze. We hope that a firmware update will be able to fix this problem.

We were very happy with the fume emissions and the noise levels on the BCN3D Sigma. These are almost similar to those of any desktop 3D printer. The noise was 56 decibels, which is still somewhat loud but pretty much within the acceptable standards. Working in a well-ventilated area is recommended when printing with this machine if you don’t want the noise to disturb neighbors or colleagues.

sigma printer filaments

Another impressive feature was the auto-calibration probe. This technology consists of a sensor that checks the level of the print bed before operations begins and that the IDEX height is adjusted accordingly.

Should You Buy the BCN3D Printer Sigma?

Setting up the Sigma BCN3D is simple and can be compared to setting up Ultimaker 2 series. Thus, the printer can be owned by any person. The BCN3D printer is designed of a large, semi-open framework that makes it perfect for use by both professionals and hobbyists.

The BCN3D Sigma is a reliable and versatile gadget. It is the dream desktop 3D printer for people interested in fused filament fabrication. It is capable of printing large objects with reasonable detail and small objects with intricate details.

We loved the IDEX system, which is an excellent innovation by the open source community. This technology makes it easy to alternate between single and dual extrusion effortlessly. The dual extrusion might however be a bit challenging for beginners. Beginners  may have more fun and satisfaction from using the single extrusion.

On the negative side, inability to reliably estimate the print time was a disappointment. This is mainly based on the confusion between the percent completion indicator on the machine and the slicer software. The problem is made worse when printing more intricate or bigger jobs. We hope future software updates will provide a solution to this problem.

The BCN3D is priced between that of the Lulzbot Taz 6 and the Ultimaker 2+. However, compared to the two printers in build volume machines, the Sigma takes the day due to the IDEX capability that it’s endowed with.

bcn3d printer review


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