Shops that have multiple metal working machines with stand-alone coolant sumps can benefit from better coolant maintenance and recycling. Small shops with as few as 5 -10 machines and large shops with hundreds of machines have successfully instituted in-house recycling & maintenance programs.
Coolants fail and are dumped due to several reasons:
Dirty Coolant from CNC Machine
These problems are all maintenance related and can be controlled with a good Coolant Maintenance Program and recycling system.
When you have a recycling program there is more than just the equipment to consider. To have a successful program you need to also maintain your coolants in the machine sumps.
Depending on the quality of the coolant used as well as contamination & production levels, you will have to set up a cleanout schedule for your machine sumps. Every machine tool has a different sump design, oil leakage, solids buildup, and production usage. Set up a schedule that evacuates the sump as required by that machine. Some sumps could require monthly cleanouts while others can go 6 months. Make sure you remove all the coolant, chips, and sludge. Follow your coolant manufacturers’ instructions for proper cleanout. The use of a high powered sump sucker (vacuum) will speed up the job and be much easier for your personnel.
Recharge coolant is what you put in a sump when new or after sump cleanout. If your coolant supplier wants the sump at a 8% concentration, this is what you recharge at. Top-off coolant is what you put in the machine to keep it filled. Normally this is at a lean concentration because of the evaporation we talked about earlier in this paper. Always add some emulsion, never straight water. This will keep your coolant in good condition by adding back into the sump fresh additives to the fluid such as biocides, ep additives, defoamer, etc. In the recycling system we add the top-off coolant into the dirty side because this is the side of the system that loses level first. This also gets the biocide and additives into the coolant as soon as possible, which helps promote tramp oil removal and kills biological growth upon impact.
As part of your coolant maintenance, use the tools and experience a good “team-mate” can provide. Your coolant supplier and equipment supplier should be on the same page with you and must see the “big picture” for your plant.
If you follow these steps and use a reliable and effective coolant recycling system process, you should see great economic and production benefits while reducing overall operating costs.