Your plasma table or laser makes some of the finest dust in your building. The cut turns metal into a fume of particles well under a micron, throws sparks and hot slag with it, and does it for hours at a time. A dust collector for that table has to pull the right amount of air through the table, stop the sparks before they reach the filters, and carry enough filter area to hold up under very fine fume.
Here is what to check before you buy one, and how the answer changes with the metal you cut.
Start with the table builder’s airflow number
A downdraft cutting table is a hood, and its builder has already worked out the air it needs. That CFM figure is in the table manual, usually by table size and by zone. Use it. A collector picked by horsepower or by what the last shop had will either starve the table or cost you more than it should.
- Zoned tables. Larger tables open dampers only under the cutting head, so the collector is sized for the active zones and not the full bed
- Water tables. A water table knocks down much of the fume at the cut. What escapes still needs capture, often from above or the side
- Enclosed lasers. Fiber and CO2 lasers with a cabinet have an exhaust port and a CFM figure from the builder, the same as any machine with a dust port
Once you have the CFM, the duct between the table and the collector is sized to it. Our guide on how to size a dust collector has the duct table and the math.
Stop the sparks before the filters
Plasma and laser cutting send sparks and hot particles into the duct. Filter cartridges loaded with fine metal fume are the last place you want them to land. Every thermal cutting system needs a way to drop or cool sparks ahead of the collector, such as a spark arrestor in the duct or a spark arresting inlet on the unit, plus enough duct length for particles to cool.
The duct should be metal, smooth inside and easy to open for cleaning, because fume and slag build up in it. Nordfab Quick-Fit duct does that, and you can see how runs are laid out on our industrial ductwork page.
Give fine fume enough filter area
Thermal cutting fume is so fine that it loads filter media quickly. The answer is more media for the same air, which means a low air to cloth ratio. On cutting tables we design at 2 to 1 or lower on nanofiber cartridges, and the surface loading nanofiber layer is what lets the pulse cleaning release that fume.
If your current collector eats cartridges on a cutting table, it is almost always short on filter area. See why your dust collector keeps clogging and how often to change dust collector filters. Replacement cartridges are on our DustHog filters and cartridge filters pages.
What you cut decides the collector
| What you cut | What changes | Where we start |
|---|---|---|
| Mild steel | Fine iron oxide fume, heavy spark load | A self cleaning cartridge dust collector with spark control |
| Stainless steel | Fume carries hexavalent chromium | Cartridge collector with a HEPA after filter when air returns to the shop |
| Galvanized or coated steel | Zinc and coating fume | Cartridge collector, with exhaust or after filtration matched to the coating |
| Aluminum, titanium, magnesium | The dust is a combustible metal | A wet collector, which is what we recommend and what NFPA 660 prefers |
| Wood, acrylic, leather on a laser | Smoke and odor more than dust | Filtration with an activated carbon stage |
For steel and stainless on one table
The DustHog PNP Plug-N-Play collector is built for this job. DustHog names thermally generated fume from welding, laser and plasma cutting as its application, and the unit arrives wired, so it needs power, compressed air and duct. DustHog rates the PNP for non combustible dry dust, so it is not the unit for aluminum.
For larger tables, several tables, or combustible dust
The DustHog SFC cartridge collector scales by cartridge count, and it is one of the DustHog families rated for combustible as well as non combustible dry dust. The full range is on our plasma and laser fume collectors page.
For aluminum and other reactive metals
Fine aluminum, titanium and magnesium dust is combustible, and a dry cartridge full of it is a hazard you do not want inside your building. Wet collection captures the metal in water. Every wet collector on a metal application also has to manage the hydrogen that reactive metal gives off in water, which is why the exhaust is ducted. Read wet versus dry collectors before you decide, and do not run aluminum and steel through the same dry collector.
If your fume or dust is combustible
Cutting dust is not always combustible. Carbon steel, stainless and galvanized behave very differently from aluminum, magnesium and titanium, so have your dust checked for combustibility. Our KSt values page lists general values for common materials as a starting point, and those published values are for screening, not design. NFPA 660 requires a dust hazard analysis (DHA) for facilities that handle combustible dust, reviewed at least every five years and whenever the process changes, and adding a cutting table is a process change. You can request the intake form at DHA Report. Our NFPA 660 guide and combustible dust collectors page cover the equipment side.
Do not forget the rest of the shop
A table collector handles the table. The fume from hand plasma, torch work and the weld stations next to it needs its own capture. That is where fume arms, downdraft tables and a portable collector such as the DustHog VP-750 come in, with ambient air cleaners for the haze that still gets away. Our pages on welding and metal fabrication and the best welding fume extractors cover those.
When a dedicated table collector is not right for you
- You run a small hobby plasma table a few hours a month. A water table and good shop ventilation may be all you need, and an industrial collector will be more than the job calls for
- Your table came with its own matched filter unit. Keep it, maintain it and order filters for it. You do not need a second collector
- You cut only aluminum. Skip the dry cartridge units on this page and go straight to wet collection
Frequently asked questions
What size dust collector do I need for a plasma table?
Use the CFM figure published by your table builder for your table size and zoning. Then size the filter area to that airflow at an air to cloth ratio of 2 to 1 or lower.
Do I need a dust collector with a water table?
A water table captures much of the fume at the cut, but not all of it. Whether you need more depends on what you cut, how many hours you run and what your air looks like.
Can I use a regular dust collector for plasma cutting?
Only if it has spark control ahead of the filters and enough filter area for very fine fume. A collector built for wood chips or general dust will blind quickly and has no protection against sparks.
What collector do I need for cutting aluminum?
A wet collector. Fine aluminum dust is a combustible metal, and wet collection is the approach NFPA 660 prefers and what we recommend.
Do laser cutters need fume extraction?
Yes. Metal cutting lasers make fine metal fume, and lasers cutting wood, acrylic or leather make smoke and odor that call for a carbon stage. Use the exhaust CFM from the laser builder.
Why do my plasma table filters clog so fast?
Usually too little filter area for the airflow. Thermal cutting fume is extremely fine and needs a low air to cloth ratio and surface loading media.
Keep reading
Matching a collector to your table?
Send us the table make, size and what you cut. You get the airflow, the collector type and a straight answer if a wet collector or the unit you already own is the better call.
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