Struggling with filtration still - Speedy 300 into Atmos Duo

[Steve Crawford]

After getting my Trotec Speedy 300 in March I've done about 75 hours engraving and cutting. My cutting is mostly MDF and engraving is wood and acrylic.

At about IIRC 40 hours, the Atmos duo was showing 100% filter usage (ie: needed replacement), I thought that was a bit too soon and as they're very expensive here in the UK, I did what the engineer who did my commissioning suggested, and took it out to the workshop and blew compressed air through the filter to try to get rid of the deposits. That did quite well, and the system showed about 55% when used again. However it did clog up pretty quickly again and in less than another 5 hours of use was again showing 100%.

It was then I found that I didn't have to run it at maximum speed all the time (as the engineer had set it to), so started running it at around 250 instead of 400 cfpm. I blew it out again and it was ok for a few more hours use. Around this time I had the bright idea of putting additional 'filter sheets' into the top box fitted above the filter to remove some of the smaller particulates, so I bought cooker hood filters and cut them to size. Again this seemed to help a little as they were definitely picking up some of the finer dust and of course would only be cheap to replace.

During an engineer visit for a table realignment, he said sometimes taking the charcoal sacks out and then replacing them sometimes helps... Again I did this and combined with yet another filter blow out it seemed to help for a while.

However it's up to 100% usage again now.

So this morning I took out the filter, pre box and all the filters apart from the charcoal. However running it with only the charcoal in as a test, still reports over 90% filter use!! Wtf! Does this mean the charcoal is screwed and it's that I should be replacing?

Suggestions would be gratefully appreciated. I'm disappointed that the filters don't seem to be giving me enough usage. I would have hoped for perhaps a couple of hundred hours rather than what I'm getting.

[Dave Sheldrake]

Welcome to the world of MDF cutting Steve, I have a commercial extraction / separation system and even that needs cleaning out once a week. Filters of any kind and MDF never do well for longevity. MDF will clog and kill the charcoal VERY quickly, Charcoal is to remove toxic fumes and not small particulates.

cheers

Dave

[Steve Crawford]

Hi Dave, thanks for the reply. Can you let me have more details on the system you use please. I need some kind of 'adequate' solution as this is my business.

[Dave Sheldrake]

Hi Steve ,

It's the Mitsubishi KRM 300 system, it has water filtering, electrostatic and carbon. It's not really the sort of thing you buy to fit on smaller lasers (I have it as I have a large metal cutter) due to price £20k+. About the only way to beat the MDF blues is atmospheric extraction if you can get approvals from the local council.

cheers

Dave

[Steve Crawford]

Right now I'm considering fitting a cyclone between the laser and the extractor. Woodworkers seem to find this is good for MDF dust which they complain of clogging their dust extractor filters until they fit one. Worth a try right?

[Dave Sheldrake]

Could give it a go Steve, I tried all sorts before plumbing the lasers into the big filtration unit, it either seems to work well and clog up or work badly and last for ages. Cyclonic may help, it sure can't do any harm anyways.

cheers

Dave

[Ross Moshinsky]

Cyclone filters work but remember every time you add a restriction, flow will decrease. You may need to upgrade the fan.

[David Somers]

Steve,

Like Dave said, a cyclone won't hurt. But remember they are designed to give larger particles a chance to fall out into a container before they get into the main filters that are removing the suspended particles and vapors. Since I don't have a laser yet, I am not sure if what you generate from lasing MDF is heavy enough to fall in a cyclone and get removed?

For example, I have a cyclone on my dust collector for wood turning. Much of the chips I produce are too heavy for a dust collector to even pull in. Especially if I am hogging out material during the roughing stages. Once I get to finer cuts the dust collector can pull it in and most of it goes into the cyclone container. Once I start sanding though most of that goes right through the cyclone and into the filter bag for the dust collector. it is not heavy enough to fall out of the stream. That is why I was speculating if the material produced by lasing the MDF is heavy enough to fall out into the cyclone container. My gut feeling is it is not.

A cyclone is cheap though so you won't have big bucks invested in the experiment.

Fingers are crossed for you!

[Dan Hintz]

Right now I'm considering fitting a cyclone between the laser and the extractor. Woodworkers seem to find this is good for MDF dust which they complain of clogging their dust extractor filters until they fit one. Worth a try right?

This topic seems to be really popular the last couple of months... was there a run on free MDF at the local Borgs?

I don't think a cyclone is going to help you in this case. Cyclones are designed to remove heavy particulate matter, but what's clogging your filters is the resins in the glue. I have warned multiple people this month alone about using MDF with straight filter systems, but the salesmen keep pushing them, so the cycle continues (I wonder what kind of commission the sales guys get from filter replacements...). You need a cheap, easily replaceable pre-filter setup to capture as much of the resin as you can, before it hits your main filters.

[Steve Crawford]

This topic seems to be really popular the last couple of months... You need a cheap, easily replaceable pre-filter setup to capture as much of the resin as you can, before it hits your main filters.

Does anyone have any ideas how to construct one or where to buy one? Seems to me that anyone using a lot of MDF will need one.

[Scott Shepherd]

I agree with Dan, I don't see how a cyclone is going to change anything in this equation. Those things are designs to remove dust in a woodworking environment, not deal with burnt glue. I honestly don't think it's going to change anything, other than your bank account. I'd be looking more into a pre filter going into the Atmos, or a multi stage pre filter, using some inexpensive filter material just to try and catch some of it.

[Dan Hintz]

Does anyone have any ideas how to construct one or where to buy one? Seems to me that anyone using a lot of MDF will need one.

I would start with a furnace static filter (the blue mesh stuff that reminds you of a thin Brill-O pad). If that captures enough, then consider yourself lucky. If not, you may need to create a water treatment pre-filter... downside to that is you'll want to use purified water, else you'll reduce the life of your charcoal bed pulling chlorine from the water (relatively minimal, all things considered, but something to keep in mind if you have to swap water every few hours... I'd have to crunch the numbers before I could say if it would truly be a noticeable problem).