Scanner Fans: AC or DC?

[thesk8nmidget]

i have read a little on fans here but still have a few questions.

can you get away with using just fans blowing air out? or is the fan blowing in and also out needed for proper cooling?

also do you guys have a link to some quiet 12v dc fans?

[carmangary]

Most catalogs specify the dB level of the fans so you can tell how noisy they are.

You can just blow air out or in as long as you have hole in your case for air to flow in/out. Think of your enclosure as a straw. If you try to suck on one end with your finger on the other, what happens?

If you want to keep it clean inside, the best way is to have positive pressure with a filter on the fan blowing in. If you have negative pressure it will suck dust in through every crack in the enclosure. Positive pressure prevents that.

[thesk8nmidget]

gotcha that makes perfect sense! thanks gary!

now i just need to find some good fans and filters.

are there any kind of filters or style of filters that you guys suggest?

[James Lehman]

Yep - that's what I used; still not a lot of fun, though!

Never realized sheet metal and thin plate aluminim could generate so many frickin' chips!!

Maybe you could go to a shop that does industrial machine and panel wiring. I use to work for one. There are these nifty tools that cut holes with a hydraulic hand pump. You just need to drill a little hole and put the cutter pieces on each side of the metal sheet and pull them together with the hand pump. It's pretty neat.

James.

[Stuka]

Maybe you could go to a shop that does industrial machine and panel wiring. I use to work for one. There are these nifty tools that cut holes with a hydraulic hand pump. You just need to drill a little hole and put the cutter pieces on each side of the metal sheet and pull them together with the hand pump. It's pretty neat.

James.

THAT would definitely be an improvement - I might have to check ihto that if I need to cut anymore holes bigger than standard drill bits!

For the folks using filters on the inlet side -
Do the thin foam air conditioner filters work okay, or are you using something else?

[DZ]

I use two AC fans in my projector: http://www.mouser.com/Search/Product...Vcp5zjww%3D%3D

They are only rated for 11CFM, so with two, maybe doing around 20CFM is plenty for my projector. The amount of CFM you need really depends on how you have your projector layed out and if you've sorta planned your "air flow path".

[Pitts]

Hey Josh..

Here are two sites you can visit they have world wide delivery ( I think)..

They sell all sorts of electronic and electro related mechanical items including fans.

Take a look at the Decibel ratings.. bigger the number worse the noise,

Some are very quiet like 27dbA etc.. watch the 40 + ones as the noise gets bad real quick.

You need to also look at voltage and airflow to suit..

Anyway try theses sites..... even if you just use it to get the model etc.. neither are the cheapest in the world but do offer excellent service.

WWW.Farnell.com

WWW.Radiospares.com

See how you get on..

cheers

Ray

[Miss A.]

Hi all,

With a (completly) closed laser case you MUST have one fan blowing IN and one fan blowing OUT. Two fans blowing in (or out) will give NO airflow in your case! Think about the draft in your home. This can only be done if you have two open windows or doors.
Another good thing to use two fans instead of one: if one of them is broken during laserscanning, the second one will continue cooling!

About the AC-DC fans: more important is to use fans with good bearings!
Sheap ones are making a lot of noise after a year because dust is comming into the bearings. The dB-value mentioned in the spec's are only with new fans, not after some years.
Most important thing: buy brushless fans! DC fans with brushes will spark inside the fan and can create electrical noise on your laser signals.

We had this problem a couple of years ago with our scanset. After using a scope attached to the X-Y signals, we found out that the fans produced the electrical noise.

Keep this in mind!

Xxx Audrey

[Laser Zone]

Get the fans with filters on them to reduce the amount of dust that enters the enclosure !!

[carmangary]

With a (completly) closed laser case you MUST have one fan blowing IN and one fan blowing OUT.

I essentially agree with everything you said but you don't necessarily need two fans. As long as you have one fan and a hole (or holes) you will be OK. This is basically how computer cases work that have no fans other than the power supply fan.