Before taking on a diamond dicing project, it is important to understand how coolant usage will affect the process and the results. When coolant is used during the dicing process, the velocity of the fluid stream, the type of coolant, the size of the nozzle, the proximity of the nozzle to the blade, and many other factors may have an impact on the precision of the cuts and the amount of waste. The degree of wear on the blade may also vary according to these factors.
Why Use Coolant?
Dicing with diamond blades generates heat, which can quickly become extreme if coolant is not used. Diamond blades that have been used with proper coolant amounts and types typically show less wear than those used in dry conditions. The most common cause of diamond blade damage is cutting without enough coolant.
Proper coolant usage increases precision and minimizes material waste by reducing the amount of chipping and cracking caused by friction during processing. The fluid acts as a barrier between the product and the blade, removing diamond and material chips and lowering the pressure on the product. Removing heat at the point of contact also decreases the risk of deformations in either the product or the blade. This allows closer tolerances and helps to save materials costs, as well as diamond blade maintenance or replacement costs.
Determining Which Coolant to Use
Cooled water is the most commonly used type of coolant in diamond dicing, with chemically pure water generally being preferred over unpurified water. Reverse osmosis is the best method for purifying water to use in coolant systems, but deionized water may be used if necessary. Water is generally cooled to about 50 degrees Fahrenheit before use. It is important to consider evaporation when using water that has been left in a tank, as the particle concentration will increase as water evaporates, making the water harder.
Since water evaporates at 212 degrees Fahrenheit, it may be helpful to add synthetic water soluble coolants that have higher evaporation points to the water being used. Temperatures may rise up to 500 degrees or higher during the cutting process, so adding a synthetic water soluble coolant helps to ensure that water will not only help to cool the blade, but that it will act as a lubricant as well. Mineral oil has a higher flash point of about 275 degrees, so some blade manufacturers recommend that oil based coolants be used during dicing projects.