The Use of Cooling Lubricant in Tool and Cutter Grinding
You know that coolant is the key to machine health and product quality. But did you know that, even under good conditions, only about 10% of the cooling lubricant used in machine grinding makes it to the hot point?
The lubrication and cooling of CNC machines is essential both for extending wheel life and for ensuring high quality output.
Is the cooling system for your CNC machine operating efficiently?
Coolant Management and Operational Efficiency
Though everyone working with CNC grinding tools knows the importance of coolant, the best practices for grinding fluid are often overlooked. This is because most people don’t appreciate that coolant is a part of your machine like any other.
As abrasive compounds on the grinding wheel remove materials from the workpiece, temperature builds, and high heat risks creating parts that fall out of spec. Coolant helps ensure a stable thermal system in which to execute your grind and flushes out chips created in the grinding process. In other words, coolant is a liquid tool that provides temperature control and removes debris.
Coolant is like any tool in your grinding process, as its quality affects the overall system quality. Clean coolant is important because it:
- Extends fluid, tool, and wheel life
- Provides consistent processes to meet tight tolerance manufacturing down to the quarter degree Fahrenheit
- Results in fewer part rejections and ensures parts have a better form and finish
- Reduces machine maintenance, which decreases cycle times and downtime and avoids costly set-up time and machine adjustments
- Keeps your machine looking new longer
In short, clean coolant and effective placement impact both your grinding machines and the parts they produce, ensuring more efficient manufacturing and higher production rates.
Following best practices for grinding fluid placement will help you experience these benefits.
Coolant Placement Best Practices
The first step is to select the right lubricant for your machine. Oil offers great lubricity to keep parts cool, while water miscible is excellent at taking heat away from parts. Many in tool and cutter grinding choose oil for its lower flashpoint, lubricity, and reduced cobalt leaching. Some machines require a specific coolant type, so make sure to check with your manufacturer.
The next best practice is to pay attention to the signs that your machine needs new coolant, which is usually around ten to 15 years. These include:
- Increased viscosity
- High levels of cobalt
- A bad smell and/or corrosion (waterborne bacteria contaminating the oil)
You must then deliver the grinding fluid via the best coolant line type for the pressure and precision you need to deliver. UNITED GRINDING machines work with three different line types:
- Modular plastic: best for low pressure; extremely flexible, making this a great choice for quick changes
- Swivel nozzles: for somewhat higher pressures; used much the same way as modular plastic, these can be tightened with threads, offering more rigidity with flexibility
- Stainless steel pipe: best for high pressure; provides the consistency wheel changer or standard wheel packs need, where the coolant hits exactly the same contact point(s) each time
And most important of all: Identify your hot point and direct the right amount and pressure of fluid to it. The “hot point” is the precise point(s) where wheel and material meet, creating the highest temperatures. Regulating these temperatures is paramount, so precise nozzle aim is essential. If you’ve chosen one of the UNITED GRINDING brands, you have access to the Tool Studio software. The software shows the exact hot point, allowing you to aim your coolant nozzles with exceptional precision.
Following these best practices helps overcome the physical challenges of cooling a grinding machine moving at 2000 RPM. Turbulence on the periphery of a wheel moving at such high speeds naturally introduces air and creates misting. Compound this with improperly aimed nozzles, and the 10% coolant delivery is an at-best figure.
Watch In The Shop Now
United Grinding’s Kevis Mitchell talks to experts in the field all about coolant in the machine grinding process, including information on carbide recycling and prefilter options. Check out this ten-minute video to learn more.