137WSO.jpg Wet Machining

Why the need for Mist Collection

Mist, including water, coolants and oil, can create a film that collects on surrounding surfaces, affecting worker morale and productivity and, potentially, health and safety. Properly selected mist collection, when correctly applied, helps to reduce this problem. A better, safer work environment and reduced maintenance is the result, as outlined in Donaldson’s Filtration Technology for Mist Industries.

Many larger businesses reclaim their coolant and filter it for re-use. Small, machine-mounted mist collectors can even drain directly into a coolant sump, minimising consumption of metalworking fluids, achieving cost savings.

 

Mist Generation

Increasing demand for precision-machined components with extremely tight tolerances has lead the metalworking industry to require faster production machines, increases in the amount of coolants, oils and lubricants used and higher delivery speeds for these fluids. Tooling speeds have also increased. These factors have affected the types of mist generated in machining processes and the types of mist collectors required to deal with them. Metalworking processes generate varying quantities of mist, droplet sizes and fume.

EDM machines, lubrication reservoirs and plastic moulding and extruding machinery also generate mist and fume.

With over 40 years of experience, Donaldson can provide mist collectors and guidance in their correct selection. Please refer to Donaldson’s Technical Reference Guide on Mist Collection of Metalworking Fluids for in depth discussion on mist collection for these operations.

Donaldson has a range of mist collectors from a single-source, machine-mounted unit right up to a central mist collector extracting mist from several collection points. Donaldson’s WSO Mist Collector with its unique Synteq XP™ filter media, is an extremely versatile collector for a wide range of operations. The WSO collector can provide a solution for water soluble coolants, straight oils or oily smoke. If machining operations change, the only modification required is a change of filters.

In addition to the WSO Mist Collector range, Donaldson have the Dryflo® MMA Mist Collector and Dryflo® MMB Centrifugal Mist Collector as single-source, machine-mounted collectors. Donaldson’s Mini-Mist and Modular Media Filter provide excellent solutions to mist and particulate fume generation.

Special Considerations

Some coolants can be detrimental to sealing and gasket materials. Full data must be provided to minimise any risk of the coolant/oil not being compatible with seals and gaskets used in the mist collector.

Duct design and component selection must consider the amount of lubricant that may collect in the ductwork prior to the mist collector. Inclined duct, fluid traps and easily assembled/disassembled ducting may need to be considered.

Application

Water Soluble

Oil

Smoke

Particulate/Fume

Milling

2–20 microns

0.5–10 microns

0.7–1 microns

N/A

Turning

2–20 microns

0.5–10 microns

0.7–1 microns

N/A

Grinding

2–20 microns

 
 
 

Metal Forming:
- Die Casting*
- Heading /Stamping

 

2–50 microns

 

1–2microns

 
 
0.7–1 microns

 
<1 micron
N/A

Drawing*

1–20 microns

0.5–2 microns

0.7–1 microns

 

Parts washing#

Up to 10 microns

 
 
 

Heat treating

0.8–5 microns

0.8-5 microns

0.7–1 microns

0.5–2 microns