Rough grinding is a phase in the entire cutting tool manufacturing process. The function of rough grinding is to shape the material into desired part geometry. Subsequently, it forms a base for fine-grinding on a 6-axis CNC.
What is rough grinding?
Grinding is a process that uses an abrasive grinding wheel to remove metal from a workpiece (in our case- carbide or HSS cutting tools).
For instance, cutting occurs when the abrasive grain of the grinding wheel penetrates the workpiece and produces a chip. Also, sufficient clearance must exist between the grain, bond and workpiece to flush the chip with coolant.
Hence, the grinding process balances these interactions to achieve the desired parameters.
These interactions feed into three major commercial grinding processes: rough grinding, precision grinding, and ultra-precision grinding. To clarify, rough grinding maximizes the material removed at the cost of surface finish. Moreover, the grinding ratio varies in the range of 1.0-5.0 in rough grinding.
Machines for rough grinding the cutting tools?
As explained earlier, rough grinding is essential for faster material removal than achieving desired tolerances and surface finish. Hence, manufacturers use various machines in the cutting tool industry, ranging from centreless and cylindrical grinding machines. The most commonly used machines on which Innovation Filter System has provided a coolant filtration system are- (To know more about us, please click here)
What do cutting tool manufacturers look for in such machines-
- Rigidity- higher ‘uptime’
- A higher material removal rate
- Low precision
- Inexpensive
- Easy to maintain- low spares cost
- Lower footprint
Why does cutting tools need rough grinding?
In cutting tool manufacturing, rough grinding is often a necessary first step in the manufacturing process.
The reason for this is simple: using a rough grinder is cheaper than a CNC machine. A rough grinder can cut deeper and faster than a CNC machine, increasing productivity.
This means you don’t have to spend as much on expensive precision equipment or maintaining and replacing it. The rough grinders also last longer than CNC machines, which wear out more quickly when used for high material removal rates.
Role of coolant during rough grinding
Grinding coolant is a liquid solution that helps reduce the risk of overheating, keeps your workpiece cool, and removes small chips of material generated during the grinding process.
Type of coolant to use
Cutting fluids are critical when using a rough grinding machine to control the cutting temperature. Hence, choosing the suitable cutting fluid or coolant is essential in achieving desired grinding results. Following is a list of qualities of an ideal grinding fluid to be considered by cutting tool manufacturers, especially for their rough grinding stage-
The purpose of coolant
During grinding, a lot of heat is produced at the cutting zone. So, a coolant helps to reduce temperatures by taking away the heat. Reducing heat generated during machining protects the grinding wheel and enhances the quality of the cut.
A coolant also provides lubrication, reducing friction between the grinding wheel and workpiece and removing the chip.
The composition of grinding coolant
Water-soluble cutting fluid is the best choice if you’re looking for a cutting fluid that will help your machine run smoothly and efficiently. Water-soluble cutting fluids are made of water and soluble oil, which mix to form emulsions that enhance cooling. Water’s high specific heat capacity makes it an ideal choice as a metalworking fluid in grinding.
Chemical properties
The quality of the cut is affected by oxidation during grinding.
When oxidation occurs, a thin oxide film gets deposited and covers the cut, affecting the subsequent coating. Water in coolants leads to oxidation, which affects metalwork quality.
Coolants have low viscosity and high thermal capacity.
Importance of a coolant filtration system in rough grinding
Coolant filtration is a great way to save money for cutting tool manufacturers.
Firstly, it extends the working life of coolant, so tool manufacturers buy less and reduce disposal costs.
Secondly, clean coolant maintains a more uniform viscosity over time, helping to keep the grinding wheel from getting clogged with particles that would otherwise cause it to wear out faster. This, in turn, helps maintain consistent grinding capabilities.
And finally, clean coolant helps prevent scratches on parts by keeping them free of particulate matter that could migrate from the grinding wheel onto the part surface.
The coolant filtration system should be designed considering the physical properties of water and the chemical properties of the coolant being used. Determining what filter media is required to remove contaminants in the coolant is also essential. We highly encourage you to contact us to discuss your precision filtration needs with our team.
Precision in rough-grinding is crucial, and your tips provide a valuable edge. Thanks for the post
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