conny_g
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Posts posted by conny_g
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Success - the 16dB low noise fan with 1,7 mm H2O pressure and 80 m^3/h airflow is enough!
Temperature the same and stable for long term prints.
Dotted lines are last test with the more powerful fan.
Problem resolved, project "cabinet" done, printers "in production" again.
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Test successful, the temperatures behave exactly as before. See diagram.
In terms of openings I have now:
- bottom / inlet: 57 holes of 10mm which results in a opening area of 4.500 mm^2
- top / outlet: 3 holes of 45mm = ~4.800mm^2
- as a reference: a 120mm fan has an area of 11.300mm^2, so inlet/outlet are about half of that area
Next test: use quieter fan, the BeQuiet Silent Wings 3 one with 30% less pressure/airflow but only 16 dB of noise.
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4 hours ago, Julian2801 said:
Could you give me some more information about what Octolapse does? Is it slicing the STL and in the GCode the head moves to the top left position after every finished layer and then the camera takes a picture? Or do you have to give Octolapse the sliced GCode and then it is being processed?
Octolapse is a Octoprint plugin that hooks into the „gcode stream“ of octoprint and modifies it slightly to move the head to a certain position between layers to take the picture.
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Laser cut a drilling template and did some drilling for a few hours - 57 holes through 19mm MDF is quite time consuming.
Also added a 3rd hole on the top side (not on the photo, did that later).
As a first version of the bottom holes I did shape the area of a 120mm fan, which results in 57 holes and 4.500 mm^2 of opening, which is half of what a 120mm fan has.
The idea is: if the airflow is enough with that, without a fan, I am happy and it's done.If the airflow is not enough I can choose to either drill more holes (2-3 times as many) or add a fan on the bottom side of the cabinet to push air in. While the 2nd fan on top pulls the air out. Resulting in twice the pressure and probably enough airflow.
Another print test to check "level 1" of the above is running just now.
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Started another 10 hours print right after this one to see if the temperature stays stable in the long term.
And it does, even after 7 more hours the temp stays at these values.
Interesting that you can see that I lowered the extruder temperature to 190 C instead of 200 C - the temperature in the cabinet decreases by 0,5 C.
Summary for all who want to build something like this:
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120mm fan with high static pressure (3mm H20 = 30Pa) on top of the cabinet.
I used this: https://www.bequiet.com/de/casefans/270
2,5-3mm H2O of pressure are the ones with the highest available in the regular PC fans area.
There is just industrial ones like this with >7 mm H2O:
https://noctua.at/de/nf-f12-industrialppc-3000-pwm
But they have 40dB. -
Inlet and outlet holes of at least 4.000mm^2. One of them larger, more in the area of the fan >10.000mm^2.
Ideally inlet/outlet would be the same area the fan has = 10.000-11.000mm^2, but my experiment shows that either inlet of half or outlet of half are already working. But both half or less does not work, that were my earlier experiments. - Inlet/outlet ideally positioned diagonally across the box, i.e. in at the front, out at the back, to ensure flow across the hole cabinet
I thought a moment about retrying the 2 50mm fans. But if you compare their technical data to the 120mm, they are too weak to achieve the same result and temperature will be higher:
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Air flow:
120mm: 120m^3/h
2x50mm: 23m^3/h -
Static pressure:
120mm: 2,7mm H20
2x50mm: 1,2mm H20
120mm: https://www.bequiet.com/de/casefans/270
50mm: https://www.blacknoise.com/datas/downloads/datasheets/TData_BSF50_122012_de_en.pdf
Both are silent fans, the 120mm produces 29dB and the 50mm only 16dB of noise. I think I will try another one of Bequiet with 16 dB next that has half the RPM and some 30% less static pressue and airflow, but still much more than the 50mm.
https://www.bequiet.com/de/casefans/718
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120mm fan with high static pressure (3mm H20 = 30Pa) on top of the cabinet.
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Now we're getting there!!
In the diagram you see the test with the fan "off" as dashed lines and the newest one with the carton door with ventilation slit as solid lines.
Now the "exhaust" cabinet where the heat is pulled to goes 2 degrees above the printer cabinet, the printer cabinet stabilizes at 28 C and the 2nd extruder (which reflects the top of the inside of the cabinet) is at a max of 32 C - which is almost 6 C lower than before.
The exhaust line is now above the cabinet line which means there is more heat pulled outside than stays inside - that's perfect.
So clearly the air inlet is the most important bottleneck for now and is way too small, I need to drill additional holes into the bottom and then it works as it does here and absolutely hits the goal that I was planning for - to stay around 30 C.The area of the carton slit is some 20x530mm = 10.600mm^2.
If I use 500mm of the width to drill a grid of 10mm holes with 10mm space in between I get 16 holes in each row.
And I need 4 rows to meet a total of 11.300 mm^2 - that's what I am going to do tomorrow.
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Here’s my carton test door with ventilation slit.
Nice what you can do with a laser cutter ?
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On 9/13/2018 at 1:02 PM, geert_2 said:
For comparison, my printers are sitting in the fume extraction cabinet in my laboratory. This extraction cabinet has an exhaust pipe diameter of 200mm. And the rectangular front opening is ca. 1100mm x 50mm. All this to get a smooth equal air flow.
Although this is designed for extraction of chemical fumes, it is just standard lab equipment, I guess the concept can be ported to extraction of heat too, since both are about getting enough air flow, and good equal distritbution.
I have no idea what fan is in there, since it is a huge central fan on the roof for all cabinets. But you can really hear and feel the airflow.
Yes, you could disassemble a mini-fridge (like those in hotel rooms), put the cooling radiator inside and the heat radiator outside. But then you are going to have that constant compressor rattle. Or you could disassemble a cooling box based on peltier-elements and use these. But I doubt if this has enough capacity? It has to remove 100 up to 200 Watt of heat. And you may get condensation and corrosion. Probably a big fan is still easier...
It seems your ventilation is a whole dimension stronger. But likely also much louder?
Good idea to place a carton at the front and test with variations of ventilation holes.
Before I buy the expensive duct vents I should do that.
And regarding active cooling... that's all too much hassle and I think it's not that much heat to be removed, a reasonable airflow should really do it. In the end I think it's not too much more heat a good desktop processor would produce. And the case fans can handle that as well, just that there is better ventilation holes in the case. -
Just now, Julian2801 said:
Looking really nice! I'm planning to build something similar (only for one printer though). Are you using some noise-canceling materials or is the wood cabinet doing the job alone?
No noise cancelling materials - foam or similar. Just the wood cabinet is enough, works perfectly well, no foam needed.
It's built from 19mm MDF material, so it's quite heavy and I think that is essential so that the printer vibrations do not make the cabinet a speaker ?.
The doors are 16mm and have 6mm glas inserts. Needs good hinges to carry the weight. And 160+ degrees hinges are helpful.
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Yes, you are absolutely right. The fans and holes are too small. Did the control test with fan off yesterday and to my surprise and frustration the temperature values don’t differ too much. Maybe 1 degree.
It seems it has much more impact if the test was run right after another one or after 10/12 hours of break, the curves are very different in these cases. Means they are 2-3 C higher if there was a test right before, even if the starting temp is the same ~25 C. Logical, the hole cabinet stored heat and will absorb less right from the start.
Looking into datasheets of fans some more I am finding that real house ventilation duct vents have 10-20 times the static pressure vs the best pressure optimized PC fans to get air through the 10cm holes in the wall. And for that they are 50dB mostly instead of 20-25 ?
Thats the key issue here why not too much air is taken from the cabinet. It needs to be 5-10 times as much air to make a real difference.
Thinking about making a test with a duct fan now ?
Or with a vacuum cleaner, they are designed for strong pressure resp. suction ?
Alternatively I build a small A/C into the cabinets, i.e. active cooling....
But on the other hand even this last print was successful. So it seems that the reduction of the feeder motor current brought the level of the filament temperature in the feeder to an acceptable level and there is no issue with the air temp of 35 C at all.
I should just keep on printing and watch out for symptoms before spending more time on this.
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Not exactly "thrilled" by the result ?
The 120mm fan did perform slightly better, but more in a negligible range.
The cabinet temperature increased slower and stayed 2-2,5 C below the temperature with the 50mm fans.
And the cabinet above increased slightly quicker and higher, so more heat was put there.
But 2-3 degrees does not really make a big difference. Now it would be interesting to do a final test without any fan.
(And btw, there is another difference in that last diagram: the temp curve of the 2nd extruder - gray line - is very different, goes up rather steep in comparison the the last test. That's probably because I had the 120mm fan in the cabinet to mix the air and avoid layering of the air temperature and that fan I used for the next test. And it seems there the temperature up in the cabinet at the height of the 2nd extruder was higher than for the thermometer at the bottom, 4 degrees of difference.)It seems that it needs more / larger ventilation holes to make this work with PC fans.
The problem is obviously their low static pressure - their airflow decreases drastically with pressure they have to build up, that's at least telling me value of static pressure and the corresponding diagrams "pressure vs. airflow".
But I don't really want to make the case that open, that will harm the noise reduction effect which is the key reason why I have them.
Another option would be a test with a real 230V ventilation / duct fan. They seem to have higher air flow (2-5x of the 120mm) and like 100x the static pressure. That should also work with small holes for ventilation. But they are much noisier and much more expensive. The quiet ones (25db and less) are beyond 100 Euros.
Or would anyone know a duct fan that is like 12V/24V and low noise, i.e. a small variant of the 230V building installation duct fans?
I think I will do a final test without fan to know the difference. And if the 50mm or 120mm fans do make a notable difference I will just keep that until I run into any issues with longer prints. A temperature of 33-35 C does look doable at this time, will just collect more experience and react if necessary.
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2 minutes ago, tinkergnome said:
Perhaps a silly question:
While you use the fan to extract the warm air, is there also an inlet for fresh air somewhere? I guess this is quite essential...
And +1 for the 120mm fan!Yes, there's a hole at the bottom back, underneath the sliding table for the cables going into the cabinet. It's not that big (50-60mm) and one of the next optimization steps. But first I want some indication that this principle works at all. Don't want to put lots of holes into the expensive & nice cabinets before having some proof of concept ?. So I am trying to approach it in small steps carefully.
For this I now want to see the two lines to change their profile: the printer cabinet line needs to stay lower and the "exhaust cabinet" one needs to go steeper.
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2 prints of this girl successful. But I am not completely happy with the temperature curve yet - see image.
The "exhaust cabinet" temperature (the cabinet above the printers where the fans are sucking the heat) is not going really high and the temperature in the printer cabinets is not really much lower than before.
I think so far the feeder current was the dominant driver as this generates more than 5 C more heat directly at the feeder. I think that this plus the +10C air temp caused the filament to become too soft to feed.So I am trying the other thing I had in mind. Put an enclosure on the two holes for the small fans, but use a 120mm fan with 2x the static pressure and 5x the airflow of the two small ones.
(Hehe, that's fun: use a laser cutter to improve the 3D printer enclosure ?).If this has slightly better performance as an indication I would drill another hole for more airflow or even make a complete cut-out of 200x50 which is about the same area than a circle of 120mm diameter.
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On 9/5/2018 at 6:20 PM, foehnsturm said:
Hi guys, holdays are over here now.
Any experiences with the sensor to share so far?
I am back from vacation for a week now, but have a lot of work at the moment. Will take a few more weeks until I get to test the sensor. ?
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After 5 hours the temperature in the printer cabinet stabilizes at 31 C, the 2nd extruder shows 36 C, the cabinet above the printer it's 28,9 C.
Print successful so far, 5 hours of 7 are done.
So it seems the fans and lowering the extruder current did the job.
But it feels kind of tight at the limit - the temperatures are not very much lower. So I will do another test with a 120mm fan which has double the air pressure and 5x the air volume than the two small fans.
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Mounted 2 pieces of 50mm fans in one cabinet for a test. That should extract some 24 m^3 per hour of warm air to the the cabinet above it - that has holes to the outside anyway (IKEA already has these type of cabinets open for any electric devices you might put there). As the warming of the cabinet was very slow - 10 degrees in 2 hours - I would hope that's enough to keep the temperature down enough for PLA.
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This is what happens to the feeder with PLA if the environment temperature is too high:
The filament is torn and it starts to wrap around the feeder wheel...
Wanted to print some quick mounting bracket today and for that change the filament to silver. And somehow it wouldn’t move at all. So I dismantled the feeder and found this.
But also found that the feeder motor was rather hot even with the cabinet door open, checked the motor current and it was set to 1.200mA which is unnecessary much.
I think to remember that they recommend 1000mA.
My 50mm Fans arrived, will add them to the cabinet this weekend and test. Have a plan B with 120mm fan if that does not work.
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2 minutes ago, owen said:
Try one of these thermal switches. https://www.ebay.com/itm/9-C-99-C-DC-12V-Intelligent-Digital-Led-Thermostat-Temperature-Controller-/321723841989
You just need to hook up 12V and a good fan.
I've been using one with a 4cm fan for a while and it works great but on a hot day it's hard to keep the temperature down for the lower temp filaments so now I have hooked up an 8cm fan.
I set it to 45C for ABS and 30C for Ngen. I take my my enclosure off for PLA but if I had to use it I'd set it for 10C to 20C to that the fan is on all the time.
I was planning with one or two ultrasilent 50mm fans per cabinet with 12m^3 / h each, that should do it. The increase in temperature was very slow, so there does not seem to be much air I have to remove to keep the temp down.Would mount it/them on the top or top back side, back bottom there is already a hole for the cables where cool air can be pulled in.
http://www.blacknoise.com/site/de/produkte/noiseblocker-it-luefter/nb-blacksilentfan-series/50x50x10mm.phpThanks for the tipp with the temperatur controller, looks like a good option. Was thinking about something I can integrate in Cura / G-Code or Octoprint like a self-made circuit attached to the Raspberry Pi (Octopi) that would be controlled by an Octoprint plugin that looks for a certain thing in the G-Code, which is configured in Cura in some way. But the Cura part is even optional, it's not much effort to open Octoprint and set the fan temp.
But maybe simple solution first and nice second and your proposed controller for the start... ?
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After the 2nd try these learnings:
- After a few hours the temperature stabilizes at 35 C air (outside UM) and 40 C 2nd (unused) nozzle
- Together with the heat from the feeder motor the PLA is too soft for the feeder and the prints fail for underextrusion resp. "non-extrusion"
So I need ventilation for PLA.
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Ok, the first thing that was happening after 2,5-3 hours is that the feeder stopped feeding.
The thermometer in the cabinet showed 32 C and the 2nd extruder had 38 C.
So it's very well possible that the 32-38 C air temperature plus the feeder motor temperature (it's a BondTech) made the PLA too soft to be extruded.
As the PLA is in the printer unused already for 2 months I forwarded it by 50cm and restarted the print.My expectation is, though, that the same will happen and it will stop feeding at some point.
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8 hours ago, gr5 said:
For PLA it will get too hot - you want the air temp below 30C. But for ABS (or anything other than PLA) it should be great. You want air temp around 35C to 40C. This will work great for CPE/nGen/PET and nylon, etc.
Just testing this, longer print in PLA.
After some 2 hours of printing the temperature in the cabinet reached 30 degrees, now let's see what happens in the remaining 3 hours.With that slow increase of temperature there will not be much ventilation required to keep it down.
Some two 40mm fans on the back top of the cabinet pulling the warm air outside should be far enough.
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No extraction / cooling yet. As the ones who print ABS (me not yet as most tries failed) close their cases to increase the temperature I am assuming / hoping that the printers do not mind a slightly increased temperature. In case this is not true for PLA and other low temp materials I can still add ventilation.
Did the first short test print today and the noise reduction is phenomenal:
The Synology disk array in the cabinet next to the printers is louder than the Ultimaker!
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Here’s my new printer cabinets to keep noise in my office down and to store them in a neat & tidy way.
Made by my favorite furniture maker.
PSU, cables, Raspberry Pi with OctoPrint are stowed in the drawers underneath the printers.
The printers can slide out for filament change or other maintenance.
The doors have gaskets so the noise can’t escape.
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Don't have much time at the moment, but I left a few points here how I did it, have a look:
Printer cabinet
in Third party products & modifications
Posted
Currently the inlet is without fan. But I designed the inlet holes so that I could put a fan there. The last results showed: no need to do so.
But who knows - maybe next summer if the office has 28 C I want to put a fan there to push the temperature even lower.
I had to decide between a large slit of 10-11.000mm^2, like i had it in the carton door.
But I voted for the holes and for just the amount that are needed for a 120mm fan because the larger any kind of opening there, the more noise can escape the cabinet.
So I thought about rather having a few holes and put a push-in fan there than to create a large opening - in the end the key purpose of the cabinets is to keep the noise inside.