Reduced Air Flow – Slippery Factory Floors
The Residue Ends Up Everywhere
In many factories I find a thin oil residue on all the equipment, floors, and sometimes even the boxes for finished products. I see that all the CNC units have Air Filtration units attached like Tri-Mist and MistBusters, and in many cases they even have HEPA filters attached. The HEPA filter is supposed to capture almost all of the oil mist, so how is it escaping into the ambient factory air?
You Could be Bogging Down Your System
Airflow restriction / the reduced amount of cubic feet of air that is passed through the filtration unit is the main cause – because of the HEPA filter. As the paper HEPA filter clogs up, airflow is reduced, this in turn causes the oil laden air to seep out of the CNC via the sides, the chip feeder, and even the underside of the CNC. A lot of times this slow dispersion of oily air is undetected from any source point, but instead slowly builds and disperses. Keep in mind that if you’re looking at the air filtration unit you may not see oily air being discharged from the top.
A more effective way to combat this problem is to:
1. Some can be so fine that they are carried into the air from sanding or friction based processes. The heavier particulate may make it to the floor but combined with oil or mist can be a disaster which can cause a slip and fall.
2. Remove the HEPA filter – in most instances they should not be used because of this issue. The HEPA filters are too restrictive for a machining application.
3. Replace the first (2) mesh filters with an oil baffle type filter. The mesh filters are designed to prevent chips from being sucked into the electrostatic cells, and consequently causing them to ground out. But these (2) mesh pre-filters do nothing to filter out the heavily oil laden air prior to reaching the electrostatic cells, this in turn causes the unit to work at a lower efficiency. By using (2) baffle type filters – (metal slots that redirect the air down, then back up and between the metals slots) causes the oil residue to condense on them and drip back down into the CNC cabinet. This allows the electrostatic cells to work at a higher efficiency – resulting in cleaner air being discharged – without reducing CFM.