CPAP blower fan?
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@clearlynotstef Not sure about that specific motor and driver, but I designed a blower based on a CPAP impeller that uses a HDD motor and a $10 driver board from ebay. See https://drmrehorst.blogspot.com/2018/04/the-mother-of-all-print-cooling-fans.html and the original post on the topic here: https://drmrehorst.blogspot.com/2018/01/the-mother-of-all-print-cooling-fans.html
The driver accepts the PWM signal from the fan output on a Duet board to control the speed, so you just configure it as a normal print cooling fan.
I'm not sure why the guy in the video was concerned enough to put the input for the blower inside the print chamber- you're not going to use a print cooling fan when printing ABS (maybe his chamber gets hot enough that it can be made to work- mine doesn't at 50C).
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@mrehorstdmd Simon is going hardcore for speed and doing speedruns (talking 100mm³/s+ flowrate) - hence the CPAP and his side cooling ducts.
I'd say the only thing to be cautious about is the input voltage tolerance of the control board. 3.3V vs 5V.
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@clearlynotstef i used a "UMLIFE DC 6-60V 400W BLDC Three-Phase DC Brushless Motor Controller PWM Hall Motor Control Driver Board 12V 24V 48V" i got from amazon and tested a cpap motor i plan to use for my hotend cooling. It tested fine using potentiometer control (since i simply want the fan always on). The pwm control on that unit is stated to work 2.5V to 5V in case i wanted to try using it for cooling. This seems unlikely though since my berd air pump can change the print finish from glossy to flat if it goes above 50%, so i have headroom to pipe more cooling if I need to. My delta can't chase those high speeds too though... until i get to work on a 3 arm per tower mod to add the constraint/rigidity (more triangles!).
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@clearlynotstef I use this one for a year now: https://fr.aliexpress.com/item/32980201709.html?gatewayAdapt=glo2fra&spm=a2g0o.order_list.0.0.d6a85e5btB7sTs
I use PWM Duex port to generate the 5V signal + RC filter to smooth the signal (not mandatory) .
The fan start at 17% (0% if you set up the minimum PWM in the config)
I limited the fan to 0.7 of the PWM in the config, too noisy for me above.Powerfull enought in most cases.
Just keep in mind to take "hot" air from the inside of the printer for ABS or shrinking filament, for PLA you can take "cold" air from the outside.
You can use a multiplexer if you use multiple tools:
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@jackantubis What is the chamber temperature when you use the blower with ABS?
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@mrehorstdmd No chamber actually, struggle to print ABS or ASA
. I'm working on full enclosure. And I take the air away from the bed so, big temperature difference between part and air, good for PLA, bad for ABS/ASA. -
@jackantubis If I understand plastics and print cooling correctly, unless you're blowing 100C air (glass transition temp of ABS), you will want to leave the print cooler off when printing ABS.
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Its advisable to have some cooling - ABS prints in simple enclosed machines like troodon/voron need 50-70% flow from the single 5015 on my machines that use them.
Even my "open air" printer (in reality, the room is ~95deg f) printing ABS at 600mm/s / 15k mm/s/s with a nozzle temp of 280C needs a touch of air for the perimeters to prevent droop on the overhangs, but the infill and bridge features are perfect.
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@mrehorstdmd I'm thinking about adding heater for the part cooler to modulate the air temperature, just to explore new ideas
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@mrehorstdmd for what it’s worth, I don’t think his concern is air temperature, but rather keeping equal or negative pressure in the chamber so as not to vent particulates into the room via positive pressure in the chamber
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@luke-slaboratory When you're printing at 600 mm/sec, are you printing in super thin layers? If you print in "normal" layers, say, 0.2 mm, at that speed the nozzle is going to come around and dump more hot plastic on top of the still hot previous layer. The resulting print is going to look like a mushroom- unless you run a print cooling fan, in which case the print is liable to crack/warp. Unless maybe you're blowing pretty warm/hot air (100C?) with the "cooling" fan.
My limited experience with printing ABS with a print cooling fan in a 50C chamber has always been equivalent of printing on an open machine- layers peel/crack and the print warps. As a result (of this very limited experience) I print without using the print cooling fan at all when I print ABS and even bulky parts come out without warping, cracking, etc. At the end of the print I kill all the heaters and let the bed cool to 40C before removing the prints, which typically takes 30-40 minutes in my printer due to the masses involved.
I've seen some high speed test videos of printing ABS and they seem to mostly print single walled cylinders which is a poor test of print quality except for precision of layer stacking. You can print single walled ABS vases on any open printer without problems unless the walls of the print are straight (like a box). Straight, thin walls will warp. The real test is printing an object bigger than your fist that has some infill and multiple walls, or long, narrow objects that maximize the forces produced by the cooling, shrinking plastic. In such prints the forces produced by the shrinking plastic will pull the print apart or warp it if you don't have a heated enclosure. That is my experience, FWIW...
How are you getting such speed/acceleration- servomotors?
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Ok so stuff came in to set this up. I use VIN hotend fans so I can’t use a fan output to drive this (need a 5v pwm signal for this driver board). Duet WiFi 2. Fw 3.3.x, new to the new firmware so not super familiar with how to make this work… can I grab a 5v pwm pin from the unused expansion header and define it as a part cooling fan such that my slicer will turn it on and off and such? Which pin? What’s that gcode look like?
Thanks in advance for any help!
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undefined clearlynotstef referenced this topic
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I'm printing .2mm layers, but this is with a 400x400 machine on a full plate - I heavily rely on autofan to control cooling - increase with lower layer times, etc.
No cracking here - once I figure out the combination for that material (bed temp, nozzle temp, and % fan needed, (all abs brands I use require fan, especially in enclosed setups) I hit print and go.
A fair portion of the parts printed are larger than my fist, same as the ones that have a narrow aspect ratio - while unenclosed, these can be risky, but i haven't experienced issues with my full-volume prints on my 350x350x300 volume.
No speed benchies here - real production values.
As for the motors - They're 2504AC's - super low inductance while still keeping high torque.
I'll have step-servos by MRRF.
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@jackantubis what dose your config file control lines look like for your Cpap blower? I’m using a duet 3 mini 5+ so I was told my 5v laser output is Shaired with out_6
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; Fans
M950 F0 C"duex.pwm2" Q2000 ;CPAPFAN
M950 F1 C"fan1" ; Fan 1, Dragon HF hotend fan on Tool 0
M950 F2 C"duex.fan4" ; Fan 3, Dragon HF hotend fan on Tool 1
M950 F3 C"duex.fan6" ; Fan 5, Dragon HF hotend fan on Tool 2
M950 F4 C"fan2" Q20000 ; Fan 6, cooling duet board 20000Hz
M950 F5 C"duex.e4heat";lightsM106 P0 X0.7 C"Part Cooler" ; CPAP
M106 P1 S1.0 T45 H1 ; Dragon HF Tool 0 Hotend Fan
M106 P2 S1.0 T45 H2 ; Dragon HF Tool 1 Hotend Fan
M106 P3 S1.0 T45 H3 ; Dragon HF Tool 2 Hotend Fan
M106 P4 H5 L100 X150 B0.05 T32:40
