1
Coolant use tips
The correct use of coolant is crucial to achieving good drilling performance, which directly affects chip removal, tool life and the quality of the machining hole.
(1) The use of coolant
1) Internal cooling design
The internal cooling design is always the first choice to avoid chip clogging, especially when working with long chip materials and drilling deeper holes (greater than 3 times the diameter). For horizontal drill bits, when the coolant flows out of the bit, there should be no cutting fluid flushing down the length of at least 30cm.
2) External cooling design
External coolant can be used when the chip is well formed and the hole depth is shallow. To improve chip removal, at least one coolant nozzle (or two if non-rotating) should be located close to the tool axis.
3) Dry drilling technique, no coolant used
Dry drilling is generally not recommended.
a) Can be used for short chip material and hole depth up to 3 times the diameter of the application
b) Suitable for horizontal machine tools
c) It is recommended to reduce the cutting speed
d) Tool life will be reduced
It is recommended not to use dry drilling for:
a) Stainless steel materials (ISO M and S)
b) Interchangeable bit
The main skills of drilling processing 2023-10-20 10:00:48
1
Coolant use tips
The correct use of coolant is crucial to achieving good drilling performance, which directly affects chip removal, tool life and the quality of the machining hole.
(1) The use of coolant
1) Internal cooling design
The internal cooling design is always the first choice to avoid chip clogging, especially when working with long chip materials and drilling deeper holes (greater than 3 times the diameter). For horizontal drill bits, when the coolant flows out of the bit, there should be no cutting fluid flushing down the length of at least 30cm.
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2) External cooling design
External coolant can be used when the chip is well formed and the hole depth is shallow. To improve chip removal, at least one coolant nozzle (or two if non-rotating) should be located close to the tool axis.
1697766973185327.png
3) Dry drilling technique, no coolant used
Dry drilling is generally not recommended.
a) Can be used for short chip material and hole depth up to 3 times the diameter of the application
b) Suitable for horizontal machine tools
c) It is recommended to reduce the cutting speed
d) Tool life will be reduced
It is recommended not to use dry drilling for:
a) Stainless steel materials (ISO M and S)
b) Interchangeable bit
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4) High-pressure cooling (HPC) (~70 bar)
The benefits of using high-pressure coolant are:
a) Longer tool life due to enhanced cooling effect
b) Improve the chip removal effect in the processing of stainless steel equal length chip materials, and may extend the tool life
c) Better chip removal performance, so higher safety
d) Provide sufficient flow according to the given pressure and hole size to maintain the coolant supply
(2) The use of coolant skills
Be sure to use soluble cutting oil (emulsion) with EP (extreme pressure) additive. To ensure the best tool life, the oil content in the oil-water mixture should be between 5-12% (between 10-15% for stainless steel and superalloy materials). When increasing the oil content of the cutting fluid, be sure to check with an oil separator to ensure that the recommended oil content is not exceeded.
When conditions permit, the internal coolant is always preferred over the external cooling liquid.
The net oil improves lubrication and benefits when drilling stainless steel applications. Be sure to use with EP additives. Solid carbide bits and indexable blade bits can use clean oil and achieve good results.
Compressed air, mist cutting fluid or MQL (micro-lubrication) can be a successful choice in stable conditions, especially when machining certain cast iron and aluminum alloys. Since the increase in temperature can in turn negatively affect the tool life, it is recommended to reduce the cutting speed.