Cooling tube compensation?



  • Okay so this one is not a big deal for me right now, I was trying to think of this on my own and see if I could modify the code I needed to, I just haven't printed the parts I need yet to actually begin testing this.

    So a friend at my local FabLab told me about this: http://www.themakerhive.com/shop/viewitem.php?productid=47

    It's a lot like the fan ducts that people print from thingiverse, the difference is the use of a (crappy) air pump. The air pump and the control circuit is terrible, however, the concept is not. I have a Kossel mini so I am always thinking of ways to lighten and speed up my cycle, or print, times. We use pneumatic tubing to guide our filament, why not our air too?

    So here is the turbine fan, with a quarter for reference, that is likely to be my air supply for my next Kossel build.

    Since this would be a long plumbing tube, I was honestly thinking of a very similar system to how sports cars spool up the turbochargers in an AntiLag system. In order to prevent a gap between when the turbine begins to rotate and the amount of air pressure being effective, the turbine will have to either begin early, or already be charged.

    I was thinking of simply having a similar type of compensation to "Pressure Advance" which would know the inner ptfe tube diameter, length of the tube, and the amount of potential air the turbine blower can output, and quickly calculate the volume of air with Bernoulli's equation integrated into it. On any printer system, it would simply just be an added Bowden tube and less fans that can look ugly (in my opinion).

    It's scalable and would be efficient, lighter, and cleaner looking.

    I'm going to do the calculations tomorrow for the step down to know what tubing I should use to have the most efficient and fastest flowing volume of air with the few fans I have here.



  • I'm researching the same thing right now. Did you test the fan with and without a tube?
    Its output pressure drops a lot when something is attached to it (I'm using a big washing machine exhaust tube now, 21mm ID).
    I have small 5015-like fans (but better quality) and some really big ones (about 100x100mm) and all of them have the same huge pressure drop issue.
    The biggest one is about 120mm and without any tubing pushes a huge amount of air even run at 12V (they are all 24V fans).

    A small 5015 fan moves more air and has more pressure when directly attached to the hotend vs any stationary fan+tube combination, regardless of the fan size, based on my very accurate wet finger/direct eye shooting sensors 🙂



  • In very simple terms, you need high pressure to move air down a small diameter tube - a fan won't do it. Consider a small compressor, such as a fish tank air pump. It might work but it'll likely be far noisier than a fan.



  • The Berd Air pumps that the op originally linked to are in fact of the type used in Blood Pressure monitor Machine and as such are designed to shift air at a very high Pressure.

    I have yet to actually run mine up to check on the noise it generates?



  • @Dougal1957:

    The Berd Air pumps that the op originally linked to are in fact of the type used in Blood Pressure monitor Machine and as such are designed to shift air at a very high Pressure.

    I have yet to actually run mine up to check on the noise it generates?

    Yes I'd have thought that would be a better proposition. Wonder why the OP called them "crappy"?

    Let me know how you get on with the Berd as I'm thinking of doing something similar. I guess pressure won't be an issue but volume air flow might?



  • Will do Ian i have never had to resort to part cooling in the past but I can see the benefit of it for large overhangs etc



  • I've been doing a bit of research and am homing in on using a pond air pump. They are designed to push air through small bore tubing which is just the job. I looked at airbrush compressors but they aren't particularly high flow.



  • My apologies for the late response, I've been crazy busy with school and forgot what section I posted this under…

    The pump from makerhive, does do the job, make no mistake, the circuit they sent with it...it's not ideal. It is noisy, very noisy in comparison to my entire printer, I can hear it from rooms away when I cannot even hear my printer when outside my door with the door shut. As of right now, my printer is either in my kitchen or in my room, I have to get up early nearly every day, so noisy interrupts sleep...plus it is bulky and inconvenient (relatively).

    The engineers I asked at my local science center said the same thing, "They are meant to move a high volume of air, they are not designed for pressure.....at all."

    And I pretty much stopped there with that idea. The style of pumps used do work, I do not like the motor choice, the motors are heavy, cheap, and the contraption is larger than it needs to be for this application.

    Honestly....since I own a 3D printer, my first thought is "Make one?"

    Think a hard drive motor would work? It's fairly low profile, not sure if it would be good with pressure, worth a try though. The type of impeller that would have to be attached to it....now that is an interesting design, I'd prefer to ask a mechanical engineer (or at least someone with a more mechanical mind than I) to design a system to mount to it. It would need to be inexpensive, easily accessible to people in all countries and environments, and could be 3D printed. It would have to be as simple as possible.

    I'll be honest...I cannot think of another motor that could be common in a lot of households that would do a better (potential) job than a HDD motor without completely creating another one.

    I also want to try changing the motor on the air pump I have or copying it to and attaching one of the Faulhaber motors I have to it. That solution would not help everyone....although we do have a lot of those motors haha.



  • Seems to me this may be an attempt to solve a problem that doesn't exist.

    Is there any evidence that the weight of a typical fan is a significant impediment to performance?

    Bowden tubes allow relocating the weight of the stepper motor plus the associated hardware - all of which weighs a good deal more than a fan.

    Frederick



  • @NoSkillzEngineer:

    My apologies for the late response, I've been crazy busy with school and forgot what section I posted this under…

    The pump from makerhive, does do the job, make no mistake, the circuit they sent with it...it's not ideal. It is noisy, very noisy in comparison to my entire printer, I can hear it from rooms away when I cannot even hear my printer when outside my door with the door shut. As of right now, my printer is either in my kitchen or in my room, I have to get up early nearly every day, so noisy interrupts sleep...plus it is bulky and inconvenient (relatively).

    The engineers I asked at my local science center said the same thing, "They are meant to move a high volume of air, they are not designed for pressure.....at all."

    And I pretty much stopped there with that idea. The style of pumps used do work, I do not like the motor choice, the motors are heavy, cheap, and the contraption is larger than it needs to be for this application.

    Honestly....since I own a 3D printer, my first thought is "Make one?"

    Think a hard drive motor would work? It's fairly low profile, not sure if it would be good with pressure, worth a try though. The type of impeller that would have to be attached to it....now that is an interesting design, I'd prefer to ask a mechanical engineer (or at least someone with a more mechanical mind than I) to design a system to mount to it. It would need to be inexpensive, easily accessible to people in all countries and environments, and could be 3D printed. It would have to be as simple as possible.

    I'll be honest...I cannot think of another motor that could be common in a lot of households that would do a better (potential) job than a HDD motor without completely creating another one.

    I also want to try changing the motor on the air pump I have or copying it to and attaching one of the Faulhaber motors I have to it. That solution would not help everyone....although we do have a lot of those motors haha.

    I wouldn't think a modern HDD spindle motor would be powerful enough. My guess would be they are 4 watts? Also, aren't they usually 3 phase brushless motors that would require a driver that interpolates the standard PWM fan signal?

    I would think a VCR capstan or head motor would be quiet and powerful enough but once again require driver circuitry.

    Widely available brushless motors and controllers for RC are not expensive and if I'm not mistaken take a PWM control signal?

    I had thought of a screw compressor design like the Autorotor I adapted to one of my vehicles only much smaller, but dont know if the tolerances required would be achievable with fused filament 3d printing.



  • @fcwilt:

    Seems to me this may be an attempt to solve a problem that doesn't exist.

    Is there any evidence that the weight of a typical fan is a significant impediment to performance?

    Bowden tubes allow relocating the weight of the stepper motor plus the associated hardware - all of which weighs a good deal more than a fan.

    Frederick

    I think it's more a question of saving space than saving weight. It can be difficult to get air to where it's needed with a fan, but may be easier with a tube.


  • administrators

    It may also be easier to get cooling from all directions around the nozzle with a tube.



  • I had this laying around

    https://www.aliexpress.com/item/NEW-DC1 … 3c4f61837d

    I wounder how much air The Berd Air pumps move? mine says 3.2LPM and if i place it it in my enclosed printer i don't hear it over the brush less fans.

    So with the pump i have i just need to follow the directions on the wiki since my pump is only 7w at 12v?

    Caution: the fan outputs do not have built-in flyback diodes, because standard brushless fan motors do not need them. If you connect a brushed DC motor to a fan output, you must connect a flyback diode in parallel with the motor. A 1N400x diode (where x = any digit in 1..7) is suitable. Connect the cathode of the diode (the end with the stripe) to the positive fan wire (the V_FAN terminal on the Duet) and anode to the negative fan wire (the FANx- terminal on the Duet). The PWM fan outputs are rated to 1.5A max current draw.

    I wouldn't need the makerhive YJ-PAD V3?

    I have a IN4007 Diode but it says its only good for 1 amp.
    Would a IN5399 diode work that i have also which is stronger?


  • administrators

    1N4007 will be adequate as a flyback diode for a 7W motor.


Log in to reply