Oil and Grease in Coolant
A good grinding operation will still dump huge amounts of oil and grease into the sump. We ran a test on a high production machine. In twenty two days of double shift we pulled out about ten pounds of oil and grease. This oil and grease clogs the wheel. Clogged wheels mean slower grinds, worse quality and shorter wheel life. Clean coolant increases diamond wheel life by at least 30% overall and as much as 50% depending on the wheel and the application. This is a saving of 25% to 35% in annual diamond wheel cost.
Solid Waste in Coolant
The particles in coolant are generally in the range of fine sand. Dirty coolant is a slurry of metallic sand. A sharp tool that is run in clean coolant will stay much sharper, longer than the same tool that is run in a slurry of coolant and metallic sand. If your tools stay sharper longer you will buy fewer of them. They will not wear out as fast and they will need less sharpening.
Benefits of Coolant Filtering
Longer Coolant Life
If you filter your coolant you will get much longer life. In actual tests we see coolant last six months and it is still doing an excellent job. This saves you on coolant costs and the maintenance of sump cleaning and coolant changing.
Case Study – West Coast Saws
West Coast Saws in Tacoma, WA has been running our filter units for three years on five machines with a unit full time on each machine. They estimate that they save $5,500 a year in coolant costs not counting the tremendous saving in labour from fewer cleanings and coolant changes. They went from a coolant change every three weeks to a coolant change every six months for an improvement of eight to one. This shop bought six thousand dollars of our filter systems and saved ten thousand dollars the first year.
Increased Machine Life
The most important savings are in machine life. Dirty coolant can cut the life of a machine in half. A machine can go ten years without a problem in a clean shop. The same machine in a dirty shop can need a major rebuild in as few as five years.
Effects on Machines of Using Unfiltered Coolant
Machine coolants need to be filtered for the same reason that oil in a car engine needs to be filtered. The oils or coolant trap small, abrasive particles. Unless these particles are removed they abrade away critical surfaces.
Machining and grinding produce a large number of particles. In tests and scientific analysis it is clear that a large number of these particles are under ten microns in size. Ten microns is a size that easily gets under seals so these small particles work their way past seals into bearings, slides, ball screws, bushings and hydraulic cylinders.
Wear Particles Creating More Wear Particles
A large number of these particles are produced in the original operation. If the coolant is not filtered then the dirty coolant carries these particles back up into the work area. As the coolant gets between the work piece and the work these particles are ground and reground. They get finer and finer. The finer they get the easier it is for them to get into critical spaces and destroy machine tolerances.
The Cost of Unfiltered Coolant
Machine life is impossible to measure day to day. It is very hard to see month to month. However, if you are filtering the oil in your $20,000 car then you ought to be filtering the coolant in your $30,000 machine for exactly the same reasons.
Other benefits of Using Filtered Coolant
• Labour savings - Clean coolant means fewer coolant changes. This leads to fewer tool changes and consequently less labour
• Faster cycle times
• Less burning
• Tighter specifications
• Cooler working temperatures – Due to less friction.
We started doing this in 1996. We started working in saw and tool grinding shops. These shops produce a tremendous amount of extremely abrasive material. They wanted cleaner shops, better quality and they wanted to make more money. All the filter systems on the market were expensive and nobody addressed the real need to make the systems pay for themselves.
Case Study – A 6 Grinder Shop
A shop with six grinders for saws and tools bought six filter units for $9,000. They bought an additional $600 in cleanable, reusable filters. They had been spending $10,800 a year in coolant use and disposal. Their coolant use and disposal dropped to $500. This is a saving of $10,000, which paid for the original investment. The labour of filter maintenance was less than the labour of sump cleaning and recharging.
This shop does ultra precise grinding. The six machines were worth about $500,000 dollars. This saves $25,000 to $50,000 a year in machine life.
The shop estimated another $10,000 a year in savings on grinding wheels because of longer wheel life and less need to dress the wheel since they did not gum up as rapidly. The shop also estimates that they can work about 5% faster with no burning.