Air filtering for Laser cutters a big must have

I will be working on making an open source Air filter that will include a hepa type filter. Tthe only component I have not located a source for yet is the charcoal bits used to remove the nasty stuff. The charcoal bits are (5-6mm long and 3mm in diamiter) thousands and thousands of short / broken charcoal drawing sticks. Roughtly the equivalen of 1.5 to 1.75 B&Q orange buckets full of cabon bits.

From Blogger Pictures

I have also been experimenting with an old Dyson vortex chamber off of a DC01 hover to pre filter the heavy particles before the cloth filter that gets clogged up with laser soot from cutting MDF and Plywood.

First stage filtering is a simple 8-10 section 300mm square concertina joined at their centers with a 75mm apature.

Second stage filtering is a 300mm square x 50mm paper filter similar to a standard carbereter filter.

Third stage filtering is a 300mm x 300mm x 250mm box filled with those charcoal bits .Without an Air filter the smell and nasty hydro carbons emited along with other nasty stuff from the laser cutter would cause complaints from your neighbours I'm sure. You would not realy want a visit from enviromental health.

An Old hover motor and its fan would be ideal to get the vacume effect needed to pull the laser cutting smoke thru the filter.

Buying Charcoal drawing sicks would be far to expensive for the quanity of charcoal required.

Edited 1 time(s). Last edit at 10/19/2011 11:05PM by BodgeIt.

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... in my first CO2-laserplotters i used comercial charcoal cartridges from deep fat fryers, actually i have a really big fume-absorber (see here, last image).

But regardless of your filters - exhaust the output of the filter through the next window!

With even the best filtering you remove nearly all of the fumes and vapours, but some nano-size particles will pass the best filter anyway ... and ye smaller the particles, ye more toxic and 'active'

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Viktor
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Is a filter needed even when you cut safe material for lasers (paper, transperancies, balsa wood)?

I totally agree with VDX that even the filtered stuff is better to throw them out the window

Do you guys think an active carbon filter, like the ones used by weed growers, would do the job ?
Here is an example:
[www.head-nature.com]

Those should be industrial grade active carbon filters and avaliable anywhere at a decent price.

... this should be sufficient - but anyhow, you should exhaust even the filtered air out of the nearest window to avoid any danger with long-time-exposure to nanoscale particles that are small enough to pass even the best filter and are much more 'active' than typical fumes ...

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

Quote

to avoid any danger with long-time-exposure to nanoscale particles that are small enough to pass even the best filter and are much more 'active' than typical fumes ...

Well, as far as I know, a active carbon filter only filters chemicals, which are able to react with the carbon, but doesn't have any particle filtering effect at all. So is there even a point in using one or would it be better to simply vent everything unfiltered to the outside ?

... you can vent all outgassing out of the window - the you will be safe ... but it will smell really bad for your neighbours .

Most filters are combinations of particle filter and charcoal, so you will catch all of the micro-particles a big part (depends on filter-quality) of the nano-scaled. But the capacity of the particle filters is limited, so after a wihile more and more will pass through.

My laser-absorber has a lifetime of maybe one year in comercial lasers, so maybe some ten years in my application. But anyhow, the filtered air goes out of my window - should be the perfect compromise ...

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

Many industrial incinerators now "wash" the smoke by bubbling it through some liquid (usually water) in more or less sophisticated ways. Seems it helps a lot reducing the harmful emissions. Has anyone tried this method with laser cutter fumes?

... you need a big volume flow for 'wet filters', so common used in professional applications, but not so usefull for DIY ...

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

Thanks Victor.. been busy so have not logged in here for a while...

The filler stages I was describing in my first post is the comercial recycling filter supplied with the laser it stands 150mm taler than the laser cutter and is about 18" square the size of a smal fridge.. as its recyling it heats up the room too much its core temp is between 35c and 38c so even though its designed to be energy saving I still pipe the recyled air straight outside else I cook myself in the hallway where its located. It has a vacume set to is 55mm no idea exactly what that means in tore. It has Filter, air quality and particle bar graphs and in the sub menus readings of BBGAS and NBGAS no Idea what they are either.

As the cloth bag fillter seems get the most clogged the dyson prefillter stops some of the heaver paricles.

As to do you need a filter well If I didnt have one I would worry that I might get a visit from enviromental health the smells made by wood and MDF are not to bad but perspex paricularly cast perspex are not nice. Extruded perspex is no problem in comparison. Even with the filter and piping out its output my partner still has a little moan about the smell if i leave the door open. Having spoken to a few people with lasers now alot even some schools do not have any kind of filters. The size of the output pipe is a standard 4" waste pipe size so fitting an extra waste pipe to roof level could be a way to dispurse the fumes and not upset your neibours. The output from the filter produces very little odor but has a huge ammount of charcoal in it "1cubic foot of charcoal".

Oh one note the filter I use uses more power than the Laser cutter uses..

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Buy the bits from B&Q pipestrap [diyrepstrap.blogspot.com]
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... yes, the energy consumption is the main drawback with comercial filters

In my filter is a high-power turbine meant for the enormous throughput of comercial lasers used for cutting steel or such ... but with reducing the suction to a minimum, enough to catch the fume, it's much more quiet and should last some ten years with the absorption capacity ...

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

The Laser cutter I have is an old Universal before Airasist was fitted as standard so when it was installed the guy adjusted the Filter suction to remove flame out when cutting 10mm perspex. hence the filter is not far off its maximum suction. Yes its very very noisy.

Original it was supplied with a 1.5" focal length lens since then fitting a 2" focal length lens and makeing a beam centering target It is much better.

[www.thingiverse.com]

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Bodge It [reprap.org]
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BIQ Sanguinololu SD LCD board	BIQ Stepcon	BIQ Opto Endstop
BIQ Heater Block PCB	BIQ Extruder Peek clamp replacement	BIQ Huxley Seedling
BIQ Sanguinololu mounting	BIQ standalone Sanguinololu or Ramps mounting	Print It Stick It Cut it

My rep strap: [repstrapbertha.blogspot.com]

Buy the bits from B&Q pipestrap [diyrepstrap.blogspot.com]
How to Build a Darwin without any Rep Rap Parts [repstrapdarwin.blogspot.com]
Web Site [www.takeaway3dtech.com]

Air Filtration Systems for Laser Cutting , which is specially designed for industrial welding fume and light weight particles, can be widely applied to many places that produce dust and oil fume and industries such as electronic wave soldering, metal processing, laser cutting, etc. It is very light and flexible. With a two-meter-long movable flexible pipe, it can be moved to different locations.

Air filters marketed for lasers are $1000 to $2500. But, the pot industry has cheap air filters for under $100:

[www.ebay.com]

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[www.matter-replicator.com]

I have just purchased an unused filter system with HEPA and Carbon from a company sale. It was designed for use in labs where soldering, adhesives and chemical vapours were being expelled. It sits nicely under my laser and is as silent as the laser itself. It manages to remove the smells and smoke from cutting leather and plastic so far.
Looking for something specifically for a laser is going to attrack big money tags but think outside the box and you might drop onto a bargin which fits the purpose.