PWM possible for AC Aquarium pump?

papilio

My guess is that it would fail on the noise front compared to what I've found, but the servo flow valve idea has been my backup concept ... in which case I'll need assistance from the group in figuring out the means of regulating it via PWM I suppose. Or SOME means of variable actuation via the Duet -- not something I've thought through yet.*

Just for fun I've now turned on the aquarium pump right next to me at my desk, and I can easily forget that it's running.

I'm assuming that the servo would need to be controlled by the Duet's fan control, is this true? Would be nice to have not just on/off but variability for bridging and such.

DocTrucker

I'm watching this with interest as both the noise and reliability of the brushed DC air pumps did concern me. My current two-pronged radial solution is a chunky beast at best.

DocTrucker

Industrial solution for noisey compresor being put the noisey bit somewhere else!

papilio

Yes, even the low low hum of my pump would presumably be placed in a sound box ... might as well!

I'd be interested in reading of your current solution, clearly you're a very clever chap!

papilio

Incidentally, my "tusk" cooling system ...

https://photos.smugmug.com/Icarus-Delta/i-5W7cSD7/1/a43834b5/XL/DSC09079_cp-XL.jpg

sigxcpu

Most aquarium pumps are solenoid vibrators, not motors. I think decreasing frequency will make them very hot or burn them.
The DC pumps for medical devices (used by Berd-Air) are not noisy if under powered. I have a 24V one used on 12V mounted on a rigid leg on the extrusion and the loudest sound is the hiss from the outlet.
There are spring mounts on thingiverse that will make it totally silent even at 24V but I didn't bother.

papilio

Thanks very much @sigxcpu! Seems I'd read that they were quite loud so I hadn't investigated further, but I'll be sure to check their pump out. I'm guessing that "under powered" is still plenty.

I did discover that the exhaust can indeed be the noisiest bit, by fiddling around with tight airflow routes I was able to get the sound muffled to the point of near-inaudibility.

sigxcpu

Search for 555 pump on aliexpress. That is the motor/pump combo I am talking about.
I am not using 3mm OD tube because that restricts airflow too much. Mine is 4mm OD/3MM ID.
Depending on the nozzle (squash the tube at the end) size, shape and position, you need to reduce the cooling from 100% (yes, even at 12V) because the plastic will cool down too quickly and it will reduce inter-layer adhesion. It is THAT powerful.
I have made an ABS job but selected PET-G in slicer by mistake. I usually print PET-G with 100% cooling, noticed it likes it like that. Didn't stop but forced 0 cooling from DWC. At some 2-3cm above the bed, with my UI set at 1 second update, that near second of 100% cooling resulted in an instant inter-layer crack
One more overlooked advantage of the cooling pumps: near instant output. I've never had/seen a fan based solution that cools when it is really needed, except maybe for big bridge layers. This thing ouputs even for short overhangs (slic3r PE enables bridge cooling when it detects overhangs).

papilio

Sounds like good news! And thanks for the search tip.

I've not yet actually experienced air-pump cooling in use, but the theory sounds good and I love getting rid of fans ... if things go as planned not one of them will be on the machine. That's why I'm so concerned about eliminating any noise I can -- running the printer now in air-print mode, everything is eerily silent.

papilio

@sigxcpu, this one look okay?

Also, for a given output which is likely to be quieter ... 12V or 24V? In any case, as mentioned earlier, don't mind building a sound box for it.

fma

@papilio said in PWM possible for AC Aquarium pump?:

Incidentally, my "tusk" cooling system ...

https://photos.smugmug.com/Icarus-Delta/i-5W7cSD7/0/cb142ea0/O/DSC09079a.jpg

Nice! Could you give us more details of your system (maybe in a new thread)?

papilio

Thank you @fma! As my entire printer design is still quite a way from being operational, I might for now best refer you to my inspiration for the tusk concept ... Michael Hackney

http://www.sublimelayers.com/2017/03/the-tusk-fan-shroud.html
http://www.sublimelayers.com/2017/10/tusk-part-cooling-for-titan-aero-and.html

fma

Thanks! Very interesting concept.

sigxcpu

@papilio said in PWM possible for AC Aquarium pump?:

@sigxcpu, this one look okay?

Also, for a given output which is likely to be quieter ... 12V or 24V? In any case, as mentioned earlier, don't mind building a sound box for it.

This one is ~3x "ok-ier" (it is the one I've bought) https://www.aliexpress.com/item/24V-DC-Diaphragm-555-Vacuum-Pump-Air-pump-High-Pressure-Micro-Vacuum-Pump/32823455502.html?spm=a2g0s.9042311.0.0.27424c4dVaBLzC

(for some reason I don't see my AliExpress link. Search for item 32823455502).

The pump itself is not so noisy, but it vibrates a bit so the attachment to the frame will make a big difference. Both my pumps are 24V, one running at 24, one running at 12. Both are attached using a rigid printed part to a 2020 frame (both printers CoreXY). The one connected to 12V is almost quiet at full power. The one connected to 24V sends a noticeable vibration sound throughout the frame and acrylic panels. They act as speakers. The main noise is the hiss sound at the outlet.

If you really want it quiet, go for this mount: https://www.thingiverse.com/thing:2849793
I was too lazy to make it.

c310

@papilio said in PWM possible for AC Aquarium pump?:

Incidentally, my "tusk" cooling system ...

wow! more text and pictures please!

papilio

Hey @sigxcpu, my new pump's on its way ... thanks for the tip, can't wait to check it out!

papilio

Thank you @c310! As my printer's yet to be commissioned I think I'll hold off on an in-depth discussion until the tusk setup as I've adapted it has proven itself in my experience, but please check out these posts by the concept's developer Michael Hackney

http://www.sublimelayers.com/2017/03/the-tusk-fan-shroud.html
http://www.sublimelayers.com/2017/10/tusk-part-cooling-for-titan-aero-and.html

Another yet-to-be-proven idea which is evident in that photo is something I'm rather excited about. I'm attempting to implement MakerGear's V4 hot end into the design. A fairly novel approach by MakerGear and welcome in my goal of eliminating all fans from the printer, this hot end is passively cooled. This is achieved by having a short, very thin-walled heat break just above the heater block. My tests upon receiving the unit, having placed a thermistor into a hole just next to the clamping collar in the custom-machined bracket, indicated that the top section of the hot end never goes above warm-to-the-touch (max temp reached was 43°C) during a two-hour run with the hot end at 260°C.

I'm not aware of the V4 having been used as a stand-alone unit previously, and quite likely never on a delta. As this hot end relies on short retractions to avoid jams it must be fed by a direct extruder, not a Bowden tube. The Zesty Nimble remote drive extruder allows this, and users find that retractions can be kept well under 1mm.

The adoption of both the tusk cooling system and this MakerGear hot end have really helped me to keep the effector assembly clean and minimalist. I've striven to keep the view to the nozzle as unobstructed as possible since I love watching what's going on. Sometimes it's fun looking back at the state of the printer's design in previous incarnations, here are a couple of images showing the massive effector head with its three hovercraft fans as I'd envisioned just one year ago!

https://photos.smugmug.com/Icarus-Delta/i-CkhbZmT/0/bcc6fe44/X3/_DSC3951-X3.jpg

And if anyone's as mesmerized by watching the Delta Dance as I always am, here's a short clip of the printer doing a first layer air-print

https://youtu.be/xSomneczjoI

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