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Why I’m falling out of love with my Sigma

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    Apologies in advance for this post being a bit of a downer. Let me just start on a good note before I delve any deeper. I love the look and design of the sigma. I love the concept behind the company – open source etc. I’ve also made some badass dual material prints which is the reason I got the printer in the first place and the reason it still remains surprisingly un-thrown out of my window.

    But…. O my God, the problems I’ve had with it!!

    I put my successful prints somewhere in the 20% range. That means that out of every ten prints I start, about eight of those will fail!

    The single biggest problem I’ve had is with slipping in the y-axis. After going around the houses with what could be the issue here I am still no closer to understanding the situation. I have of course adjusted the tension of the belts many many times, lubricated the sliding mechanism and very other thing I could think of.

    The second biggest problem I’ve had is with grinding of the filament. I tried everything suggested – adjusting the tension of the ‘grip’. Adjusting the heat of the print. Lowering the retraction. Changing to a different supplier of filament. Adding the thermal compound. Still the problem remains.

    Other issues I’ve had, whilst numerous, have been relatively minor and have not affected too many prints before I’ve been able to fix them.

    The latest I’ve heard is that I need to sent the whole printer back to Spain which I’m guessing will have to be done at my own expense. I say latest because support seems to have gone on holiday and even though I have messaged them back twice I haven’t heard anything in nearly a week.

    The reason for this rant is that I think I cannot be the only one having problems and wanted to remind BCN3D that after sales care is more important that sales. The ones who’ve already purchased your machine are fans already – you should treat them right. Every forum post on here should be looked at by someone from your team – I’ve seen quite a few people with problems who are just ignored. I think you initially shipped an amazing product but it had issues. You should take responsibility for these issues willingly and enthusiastically, not begrudgingly.

    So in summary, I’m falling out of love with my printer but I still have a big soft spot for it even though it does not really deserve it at this point. Please put more stock in customer support – you made something really cool, make sure it stays really cool when it is in the hands of the people you sell it to.

    end of rant.


    Your y-axis problem sounds familiar to me. It was the first issue with our Sigma, instantly recognized during the first print. In our case one of the y-rails had multiple tiny cracks. This caused the pulley to stick and therefore the stepper skips more or less arbitrary. The sticking could be felt when slowly moving the axis. (If you move the axis by hand, the required force must almost be constant. Otherwise something is odd.) First we tried all the maintenance advices (belt tension, cleaning, lubricating, axis alignment) As nothing helped we removed the (left) rail and discovered multiple scratches on the shiny surface. Under a magnifying glass these scratches turned out to be cracks. Since the BCN3D-support did not respond, we turned to the vendor of our Sigma. After this BCN3D sent us two new linear bearings that solved the y-slipping problem. Further, we were informed that we had risked our warranty by removing the bearings unauthorized.
    Beside this we have currently some let’s say minor issues with our Sigma too. For example, the poor x-y-resolution which I mentioned in another thread. We have the hunch, that in the Sigma the micro stepping is inactive. Probably because the stepper motors would be otherwise too weak to run the machine properly.
    And has anyone noticed, that with the actual firmware the front right sector of the build plate (glass) is 0,1 mm too high after calibration? In the current firmware source code, the z-offsets for the left and right probe differ by 0,1 mm. Unfortunately, the machine does run with the self-compiled firmware, so we stick to the pre compiled version for now. Is there anyone who did a firmware update with the source code (not the pre-compiled) available on GitHub?


    Even though all the above is me being honest, I still feel a bit dickish to have posted that publicly. Can’t see where to delete it so if you’re a mod on this forum feel free to do this for me. In the meantime please get back to my support enquiry. Thanks.


    lukel, you are absolutely right and don’t have to be sorry for this.
    It is a great printer for a very competitive price. And for its features Sigma is definitely far ahead than the others.
    BUT you can clearly see that it is just too raw and has a lot of childhood diseases. And one has to wait until the company overcome these problems and improve it to a reliable machine as for instance Zortrax M200 is.
    And here unfortunately I don’t see a lot of progress and feedback from BCN. A lot of ignored issues, a lot of answers like – “I don’t know, it works for me…”.
    BCN, can you please turn Sigma from a cool toy for enthusiastic tinkerers to a solid professional grade 3D printer?


    Thanks for backing up my experiences guys. Maybe I should actually retract my retraction. I guess I just don’t want to come across as mean or vindictive or trying to shit on someones business – especially as 3D printing is just cool and I want every honest company to do well in this space. Perhaps though these problems with both the sigma, and how BCN seem to be resolving these issues need stop be brought to the fore. Maybe airing dirty laundry is not so bad as it gives them a chance to do something about it.


    Hello Luke,
    I’m sorry to hear all the issues you had to go through with the printer.
    We have not recived any answer since our last response on septembre 2. If you see there’s no respone from us in 24h don’t hesitate to contact us again at, or send another ticket.
    Hope we can solve the issues you are having so you can have your printer up and runing again.


    You might have an issue with your email as I replied on the 2nd, and sent a follow up on the 7th. Both are showing as successfully delivered from my end. I have sent the replies to the email address you suggested and thanks for getting back on here.

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