COMPLETE "Project Whisper" Making BigBox Quiet

Discussion in 'Guides, Mods, and Upgrades' started by JvdP, Mar 26, 2016.

  1. JvdP

    JvdP Well-Known Member

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    Intro
    BigBox is a fantastic printer, but it definitely isn't quiet. It's the loudest printer I've owned so far.

    This is the first post part of a project I call "Project Whisper". Although it's impossible to get the BigBox to be whisper quiet (30 dBa) I will try my best to get close ;-)

    Quick overview for reference:

    1. PWM Fans + Controller
    1.1 The BigBox Fans
    1.2 Control; The Quick 'n Dirty way
    1.3 Control; The fan controler way
    1.3.1 4-wire PWM fans
    1.3.2 Getting the 12V​
    1.4 Control; The Arduino way
    1.5 Mounting the fans​
    2. Stepper Motor Dampener
    3. Enclosed cabinet
    4. Dampening feet

    1. PWM Fans + Controller
    All together, my Dual has 7 fans and even with just 3 of them running at idle it's pretty uncomfortable to sit next to the printer for more than 10 minutes. So lets do something about these fans!

    1.1 The BigBox Fans
    BigBox has the following (2-wire, 24v) fans:
    • Inside Power Supply 60x60x??mm
      Has temperature control already from the PSU and is therefore already quiet.

    • Case Fan Next to Power Supply 60x60x11mm
      Between the power supply is only 26mm of space, so we need a slim fan here if we want to replace it. 25mm would be too thick and would make noise since it would be too close to the PSU.

    • Case fan RUMBA 50x50x12mm
      This little monster is probably to blame for most of the fan noise, at least during idling. Replacing it with something bigger (80mm) would be a really good idea. However here aswell we have very little space. A 15mm thick fan would fit, not bigger.

    • 2x Hotend cooling
      I'm not sure why these are so loud, but they are noticably louder than my other v6 hotend fans that I have. Is it the 24v? Well, for now we will leave them as is since these are quiet important!

    • 2x Print Blower
      Obviously, we need these to go fast when we want, not much we can do. However, perhaps that making the 90 degree bend slightly less abrupt would benefit the noise...?

    1.2 Control; The Quick, Dirty and Cheap Method

    You can keep your existing fans and tone them down in a few ways. However, if you set it too low and the printer gets too hot, bad things can happen. Is that worth it? I don't think so. I would hop over this section and look at a more sophisticated way.
    1. Voltage regulator
      You can simply add a voltage regulator to take the 24v of the fans down, works on the existing 2-wire fans. They will run slower and you can control the speed by changing the voltage on the fly with a simple buck converter like a simple LM2596.

      Here's an example on eBay, it will run you just $1.39 €1.25 £1.

    2. Manual PWM Controller this controller simply controls the voltage to the fan by PWM so it works on normal 2-wire fans. This does not work with brushless fans (thanks Ulrich!). Also, this gives no temperature control, so then you might as well go for the buck converter...

      ($4.5 €4 £3.2) example on eBay
      s-l400.jpg

    1.3 Control; The better way, the fan controller way
    With PWM fans (also called 4-wire fans) we get control over the speed in a nice way because the fan reports its speed back to the controller. If you want to learn more about 2-wire, 3-wire or 4-wire fans, check out this article. You could even detect broken fans this way. However, since the BigBox fans are just 2-wire fans this upgrade will require you to buy new 4-wire fans!

    Look for a 4-wire PWM controller. There's loads of fan controllers out there. Here's 2 examples that you could choose from:

    1. Simple Temperature PWM Controller, up to 3 fans, 1 thermistor, does only simple settings with a dipswitch.

      ($5 €4.5 £3.5) example on eBay
      3DCACF56462366CA633CD299267363D29DC826C799D2CA9E0326D2BE469A3363733663CC8B93CACE9DF5CD.jpg

    2. Advanced Temperature PWM Controller, up to 2 fans, 2 thermistors, display and very accurate settings.

      ($8.5 €7.6 £6) example on eBay
      s-l500.jpg

    Here's my finished setup with the advanced temperature PWM controller.

    5d2329a3-9059-421d-9bf3-87409fae987b.jpg

    1b0821be-2cec-436d-ad17-1984a0e457e3.jpg

    One thermistor is attached to the power supply and will operate the fan next to it between 20C (10% speed) and 40C (100%). The other probe is next to the RUMBA and controls the cover fan between 20C (10%) and 35C (100%).

    1.3.1 4-wire PWM fans
    • Case fan near Power Supply
      Was 60x11mm, replaced with 60x15mm PWM
      Example from eBay ($5 €4.5 £3.5)

    • Case fan over RUMBA board
      Was 50x12mm, replaced with 80x15mm PWM
      This one is more difficult. I didn't find any 50mm PWM fans. You need a very thin fan here. In the end I found a 80x80x15mm fan, but it was rather expensive... To save money you could look for a 60mm or 70mm that would fit.
      Example on eBay ($13 €11.6 £9.2)

    1.3.2 Getting the 12V
    Remember that buck converter from earlier? Well you can use it here too. You can also buy a fixed 12V converter, but I just had this variable converter lying around so I used it. It's rated up to 2A without heatsink so it will do fine.

    LM2596 DC-DC Buck converter ($1.39 €1.25 £1)


    1.4 Control; The Arduino way
    @Rob Heinzonly Has also been working on a fan controller, but he is stepping it up a notch, with an Arduino. Here's a quote from him explaining it. Lets hope he will keep us up to date!


    1.5 Mounting the fans
    Keep in mind that any vibrations that are transferred to the frame will be amplified. If you prevent this from happening you will reduce noise. Luckily, there are readily available solutions for this! Rubber fan mounts are cheap and easy to get on eBay.

    Here's an example, ($3.4 €3 £2.4)

    s-l1600.jpg


    2. Stepper motor dampener
    The Y-axis is most noisy at least in my case. I think it's because it's mounted to the backplate of the printer and therefore it resonates the whole printer. I've already had these dampeners on other 3D printers and had great success with them. I've installed on on the Y-axis motor between the motor and it's bracket. It made a big difference! I haven't seen any print quality degradation either, so all in all an easy and cheap upgrade.

    By the way, I wouldn't trust eBay on this one. They might use a different shore hardness on the rubber. You want the original Astrosyn one in this case. Do a Google search on where to get them, I got them straight from Astrosyn themselves.

    $_1.JPG

    3. Enclosed cabinet
    An enclosed cabinet is great for many things:
    • Prevent drafts during ABS printing
    • Increase chamber temperature resulting in better quality and stronger prints
    • Reduce noise
    • Hide the printer if you don't want to see it.
    Since I don't print with ABS much I did it mostly for noise reduction. I used the existing wardrobe that I had and made space for the BigBox and then lined the inside with noise dampening pyramid foam. When the door is closed you can hardly hear it!

    IMG_3068s.jpg

    4. Dampening Feet
    I know RichRap gave the tip of using the foam that came with the BigBox to dampen vibrations onto the surface. However, I found a way that is much more effective; squash balls! They are a small investment but really worth it. I added some electric tape so they move with the printer when I need to move it around. The tape does add some stiffness but since the balls were too soft to begin with works out pretty good. I based my idea off this Thingyverse part.

    Other ideas
    • Upgrade to a 32-bit controller with more microstepping
    • Replace hotend fan with better quality one?
    • Stiffen back panel to reduce Y-motor resonance
     

    Attached Files:

    #1 JvdP, Mar 26, 2016
    Last edited: Jan 4, 2017
  2. PsyVision

    PsyVision Moderator
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    Excellent! Thank you so much for the writeup!
     
  3. UlrichKliegis

    UlrichKliegis Well-Known Member

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    When shopping for new fans, spend some attention to their genuine noise level.

    There are el cheapos with straight blades, friction bearings, poor manufacturing that can drive you up the wall.

    Then there are fans with specially shaped propellers, quality bearings etc. Better already.

    And then there are fans driven by brushless motors. Stop! Although they run superquietly at any analogue voltage, they stop immediately when fed a PWM signal. That's too much for their simple electronics which is a voltage to frequency converter plus some amplification to get the coils under juice.

    Also important how you mount them. Fix them tight with screws on a rigid frame, and they will transfer all noises (whenever a blade crosses one of the carrier beams, there is a short compression of the air between them, disseminated as noise). So, a soft, flexible mounting plus some measures to steady the airstream (condenser principle) will be helpful for your ears. Mount them between rubber bands instead of a rigid fixation, and you gain several dB of relative silence.

    Tangentially working fans are generally much softer than the axial ones - although bulkier.

    You can get them to whisper, but it's always a combination of techniques.

    Alternately, get a good set of headphones, and put on some good music.
     
  4. JvdP

    JvdP Well-Known Member

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    You're right Ulrich, however it's not exactly easy to find a good fan for a reasonable price when you're just buying one-offs. I have to rely on Aliexpress, eBay and the likes here in Norway. Please share your findings here if you have anything better?

    I've bought a few Arctic F8 rev.2 fans off eBay and I find them to be really good bang for buck. However, this fan is too deep to fit between the cover and the RUMBA board and a slim version is needed.

    With regards to the rubber fixing, thanks for reminding me! I used these fan rubber mounts. I've added this to the main post with links to eBay.
     
  5. mike01hu

    mike01hu Well-Known Member

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    I am wondering whether putting a small electrolytic capacitor across the PWM output would offset the problem with brushless motors so that there is a little electrical energy available during the PWM's OFF period to keep the fan's on-board electronics alive. I can't try this myself at the moment.
     
  6. elmoret

    elmoret Administrator

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  7. UlrichKliegis

    UlrichKliegis Well-Known Member

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    The C would have to be small enough to save the DC content of the integrated pulse chain. Then, you have a smoothed yet still pulsing DC voltage. Make the C too large, then it will charge up to the maximum voltage and feed the fan at full revs.
    Unfortunately, the Arduino lacks a direct analogue output. Some more or less sophisticated circuitry is necessary to re-convert a PWM signal into a steady analog DC voltage.
    I 've found that hooking up a fan like this to one of the fan outputs of a rumba will only move air at 100% CW feed.
     
    mike01hu likes this.
  8. UlrichKliegis

    UlrichKliegis Well-Known Member

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    Here is a link to the fan department of reichelt, a german shop that ships worldwide - Norway should not be a problem. I order most of my hardware items there. So far, I have never been disappointed by them.
     
  9. JvdP

    JvdP Well-Known Member

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    Brushless fans work fine on the controller, I can confirm that they work fine. Ulrich, remember that 4-wire fans work with a control signal that is PWM, the actual power supply is separate. The fan itself will regulate it's speed depending on the PWM signal coming from the controller.

    Please stop the discussion regarding brushless fans. I feel it's off topic. I'd be really happy if other people share their projects in making their BigBox quiet!

    Thanks for that link, I'll nose around there a little. Really miss amazon here in Norway and other online shopping opportunities.
     
  10. UlrichKliegis

    UlrichKliegis Well-Known Member

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    Jos, you raised the topic of using different fans. I contributed my experience with brushless fans on a rumba's pwm output. When I discussed that several months ago in the german usenet ng de.sci.electronics, I got several confirming replies.

    But I will refrain from now on from commenting in this forum. Meet me on G+

    Cheers,
    Ulli.
     
  11. mike01hu

    mike01hu Well-Known Member

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    Not "off topic" as this is in "Guides, Mods and Upgrades", exactly where it should be ;-)
     
  12. mike01hu

    mike01hu Well-Known Member

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    That one has a good blade shape too that should run quieter. C of about 0.5uF may be adequate.
     
  13. gearmesh

    gearmesh Well-Known Member

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    I am following this. I like where it is going
     
  14. R Design

    R Design Well-Known Member

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    @JvdP nice work....

    Big question is, how much time does BB now spend being whisper quiet?

    Is it during printing if the room is at 16C?

    For the first 15mins of printing?

    Or only when on standby?
     
  15. JvdP

    JvdP Well-Known Member

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    I think we had a miscommunication, that's also the reason why I said we shouldn't continue the discussions whether "can you control a brushless fan with a PWM signal?". Let me clarify what I meant with PWM, for more information check out this post on PCBHeaven. There are 3 types of fan wirings:

    • 2-wire fans: Ground and Vcc
    • 3-wire fans: Ground, Vcc and a Tacho signal wire from an hall effect sensor that measures fan speed
    • 4-wire fans: Ground, Vcc, Tacho and a Control PWM signal which sends the "wished" speed to the fan from the controller.
    You guys are talking about 2-wire fans and controlling their speed with PWM. I'm talking about 4-wire fans, also called "PWM Fans".

    To make matters even more confusing, the first controller I showed in my examples is of the first kind (2-wire fans) and the other 2 controllers require 4-wire fans. That's also why it is difficult to find the right fan, because there are not a whole lot of 4-wire fans out there.

    I will make this clear in the main post.
     
  16. JvdP

    JvdP Well-Known Member

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    The temperatures never reach the upper threshold (maybe in summer?) and thus it stays pretty quiet. My room is about 21C at the moment.

    I think the story of fan noise has several aspects. The controller obviously takes the speed down which lowers the noise, but also I think my 60mm fan is a lower wattage thus displaces less air.

    You could argue that moving less air is bad. Less air, higher temps, right? Well that's where the fan controller steps in. I'm confident to reduce the fan speeds because I know that it is controlled.

    That little 50mm fan above the Rumba is probably to blame for most of the noise (especially while idling). It's a little monster of a fan! Replacing it with a bigger fan shows drastic improvements so I think this would be a good place to start.

    I shall write a little more about fans in the start post.
     
    #16 JvdP, Mar 27, 2016
    Last edited: Mar 27, 2016
  17. Rob Heinzonly

    Rob Heinzonly Well-Known Member

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    @JvdP : That is funny, I'm working on the same project, but with a slightly different approach. I will mount an Arduino Uno in the base of the BigBox. The Arduino will PWM the fans. I will install two DS18B20 temperature sensors. One measuring the incoming air and one measuring the air going out of the case fan. I can't use a fixed temperature to control the fans, because the summers can get quite hot and we don't have air conditioning.

    Currently, when the case fan is running at 100%, the exit temperature is about 7-12°C above room temperature. I think I will let the Arduino do a PID on the temperature difference and I will PWM the fans with the output signal.

    And maybe in the future let the Arduino chat with the Pi or the Rumba. So much to do, so little time :)
     
  18. mike01hu

    mike01hu Well-Known Member

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    Sorry JvdP, no offence! I've taken these fans apart for other purposes to try and work out effective control in that application. As Uli says, the 2-wire fans (and 3 wire) are not happy with PWM but, because 2-wire are readily available, we can try to circumvent the worst of the limitation. I'm still playing by ear, so to speak o_O
     
    #18 mike01hu, Mar 27, 2016
    Last edited: Mar 27, 2016
  19. elmoret

    elmoret Administrator

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    It is not a problem to use PWM with a 2 wire fan - that's what the BigBox does with the print cooling fan.

    Also, UlrichKliegis: A brushless DC fan is does not have a voltage to frequency converter. It has a hall sensor for detecting rotor position and energizing the appropriate motor winding as a function of motor position. The speed of the motor is a function of the voltage as increased voltage produces additional current through the winding, which results in increased torque with which the fan blades can be driven faster.
     
    #19 elmoret, Mar 27, 2016
    Last edited: Mar 27, 2016
  20. JvdP

    JvdP Well-Known Member

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    Wow, that's a great way to do it!

    On my controller I can set the lower and upper thresholds for both fans individually. For example set the lowest speed (10%) at 20C and the highest speed (100%) at 30C. This way you can compensate for warmer ambient temps. However it can't do a "X degrees above room temperature PID loop" so I'm excited to see what your Arduino project will bring.

    I'd love to have your project to be part of this. When you get the time, please do a short write-up. I will then put a summary with a link in the main post.
     
    #20 JvdP, Mar 27, 2016
    Last edited: Mar 27, 2016
    Rob Heinzonly likes this.

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