Author Topic: Good exhaust fan plus PWM control  (Read 4769 times)

Pawpawpaw85

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Good exhaust fan plus PWM control
« on: December 11, 2016, 07:47:56 AM »
I built a custom enclosure from Masonite board and used a 80x80 regular 12V PC fan (usually around 2W) for exhaust and a flexible tube for it. However the power to extract the fumes and smoke was not good, getting a strong wind against the window forced smoke the wrong way.

With that in mind I decided to search for a better fan, and luckily Delta company is still going strong. I was able to find an 18W 12V fan (80x80) named Delta FFB0812UHE that can provide a huge amount of airflow and pressure for its size. It cost around $30 on eBay and you usually need to strip the "extra" components from its mounting brackets they usually come mounted on for a SUN system.
The downside is that at full speed, it's very noisy, and very seldom will need all the power it gives running it at 12V (only on very windy days).

So I purchased a cheap PWM controller from Banggood and run it from that, it's a great way to control fan speed of these powerful fans ( http://www.banggood.com/Low-Voltage-DC-1_8V-3V-5V-6V-12V-2A-Motor-Speed-Controller-PWM-1803B-p-961010.html ).
The fan speed scaling is not linear but I'm able to set the fan speed to a decent flow vs noise level with it.
I also made a custom 3D printable housing for the PWM controller that one can find here if having a similar idea: http://www.thingiverse.com/thing:1958914

I can highly recommend this setup, it's great!
You will also want to use a fan grill with this fan, getting a finger or similar into the spinning fan blades of this fan is very dangerous.



« Last Edit: December 11, 2016, 07:57:22 AM by Pawpawpaw85 »

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Re: Good exhaust fan plus PWM control
« Reply #1 on: December 11, 2016, 07:49:37 AM »
Sweet...!!!
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Zax

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Re: Good exhaust fan plus PWM control
« Reply #2 on: December 11, 2016, 08:28:33 AM »
Very nice!

I wish I had your skills at creating 3D models, as always thanks for sharing your design.

Agastar

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Re: Good exhaust fan plus PWM control
« Reply #3 on: December 11, 2016, 10:07:49 AM »
Yes, ditto on the skills and thanks :)

Pawpawpaw85

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Re: Good exhaust fan plus PWM control
« Reply #4 on: December 11, 2016, 11:56:33 AM »
Just keep practicing Zax :)
I design things like this for a living as well so it's quite easy, but if you spend time with the programs I'm sure youll be able to make great things too!
And since you now got a 3D printer you can test things out quickly too :)

Thanks guys. I think if you dont want to go with a huge exhaust fan a 110V or 230V, this is a great fan to use. Just make sure not to connect it through the Eleksmaker board, not sure it can handle the load at fan outlet :) (the PSU I got in the kit cant, had to use a separate 12V one :)

Agastar

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Re: Good exhaust fan plus PWM control
« Reply #5 on: December 11, 2016, 06:03:05 PM »
This is not my design but it's a pic that best resembles what I want to do. It adds an activated carbon filter to reduce the smell. I'll have to work up a model :)

Pro Tip: designing for 3D printing is a little different than just creating a 3D model. :)

Pawpawpaw85

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Re: Good exhaust fan plus PWM control
« Reply #6 on: December 11, 2016, 09:22:34 PM »
Wont active carbon get saturated very quickly by the smoke from our lasers if being so small volume?

Agastar

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Re: Good exhaust fan plus PWM control
« Reply #7 on: December 12, 2016, 04:32:49 AM »
Not sure but I want the box to have two slots in it so that you can slide in two carbon filters and then a space between the filters where you can fill it up with activated carbon that you can get online or from a pet store.

Either that or make a tube based one that would hold a lot more activated carbon.

Pawpawpaw85

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Re: Good exhaust fan plus PWM control
« Reply #8 on: December 14, 2016, 09:06:31 AM »
Do you have any source of these filters and active coal you are going to be using? What kind of vaccum is needed to push air through it do you think?
Perhaps I could help designing something? Do you have a 3D printer available as Agastar?

Agastar

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Re: Good exhaust fan plus PWM control
« Reply #9 on: December 14, 2016, 11:06:30 AM »
My plan is to use a 120mm server case fan that has a high CFM that I'm planning on using. This fan is loud and probably overkill but I'll dial it down with a fan controller like you have.

I picked up this filter from Amazon and I'm going to cut it into squares that I can insert into the filter housing.

For the activated carbon, I have a jar of this that I picked up from my local pet store but here is a link to the same stuff on Amazon. Activated Carbon

If the square design doesn't work, I want to do a tube shaped one that can be 3D printed as well.

I welcome any design help you are willing to give :) I have done several 3D models for printing but I'm still a little slow :) I had an Ultimaker 2 but had to sell it last year to replace the transmission in my truck. I sold it to a friend of mine that does this stuff for a business and he already had 3 Ultimaker 2s. I gave him a good price on it and he prints my stuff for free now so I do have access to one.

Pawpawpaw85

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Re: Good exhaust fan plus PWM control
« Reply #10 on: December 14, 2016, 11:36:31 AM »
I think for such dense filters, axial fans may not give enough pressure if I understand you correctly, you want to run the airflow through both plain dense filters, and "loose" active carbon as well?
I guess it depends on how dense the filters are, one may have to stack several axial fans to get a good airflow through them.

Agastar

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Re: Good exhaust fan plus PWM control
« Reply #11 on: December 14, 2016, 12:08:44 PM »
Yeah, I need to find some scrap plywood and put a test rig together to see if it will even work the way i'm thinking lol.

pedwards2932

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Re: Good exhaust fan plus PWM control
« Reply #12 on: January 17, 2017, 04:08:22 AM »
I am getting ready to make a ventilation cover for my engraver.  I was looking at this: https://www.amazon.com/Attwood-Quiet-Blower-White-4-Inch/dp/B003BMATFK/ref=pd_lpo_200_bs_t_2?_encoding=UTF8&psc=1&refRID=DFE9MTKFBZ6BNJ1GXPRP as a cheap alternative for ventilation....I could power it with my battery charger.  They also have this https://www.amazon.com/POWERTEC-70150-Rectangular-Dust-4-Inch/dp/B00M3JFNOO/ref=pd_sim_200_3?_encoding=UTF8&psc=1&refRID=CS6BFZPRQMQ18PZ7XMAG for the hose connection.

The enclosure I haven't totally figured out yet but there were some plastic storage boxes I saw at walmart that looks like they would work.  Wonder if there is something I could paint them with that would make it so they would be safe visual protection?  If not I'll just build something but for $9.00 it would be a cheap alternative.  This looks like it may work: https://www.walmart.com/ip/Hefty-72-Qt-Hi-Rise-Clear-Latch-Box-Teal-Sachet-Lid-and-Handles/49660495
« Last Edit: January 17, 2017, 04:59:25 AM by pedwards2932 »

Agastar

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Re: Good exhaust fan plus PWM control
« Reply #13 on: January 20, 2017, 02:37:31 PM »
Yeah! Those are pretty cool looking :)