End Mill Coolant Hole Placement for Long Bottom Blade Wear
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Solution Overview
Problem
End mills with long bottom blades experience increased chip production and impaired chip discharge performance during longitudinal-feed or ramping processing, leading to chip clogging and flank face wear, which complicates reliable coolant supply and reduces tool life.
Innovation Solution
The end mill design features twisted chip discharge grooves with coolant holes that open to both sides of the long bottom blade, ensuring effective coolant supply and chip discharge, while maintaining strength and preventing flank face wear by optimizing coolant hole placement and peripheral blade leads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If long bottom blades are formed at the tip portion of the end mill body, then the cutting capability is improved, but chip discharge performance is impaired and chip clogging occurs
Solution Approach 1:
The end mill blade is segmented into multiple bottom blades of different lengths (long, middle, and short bottom blades) arranged alternately. This segmentation allows each blade to handle different portions of chip discharge, preventing clogging while maintaining cutting capability. The long bottom blade performs primary cutting, while shorter blades assist in chip evacuation through their respective grooves.
Solution Approach 2:
The end mill employs asymmetric blade length distribution with long, middle, and short bottom blades instead of uniform lengths. This asymmetry creates varied chip discharge paths and groove configurations, enabling efficient chip evacuation from different radial positions while maintaining effective cutting edges throughout the tool life.
2Power
If long bottom blades are formed at the tip portion, then cutting performance is improved, but flank face wear is promoted and service life is shortened
Solution Approach 1:
Different portions of the end mill blade have different lengths and functions. The long bottom blade provides extended cutting capability for deep grooves, while middle and short blades provide additional cutting edges that engage workpiece material at different stages. This local quality variation ensures that wear is distributed across multiple blades, extending overall tool service life while maintaining consistent cutting performance.
Solution Approach 2:
The alternating arrangement of long, middle, and short bottom blades creates periodic engagement patterns with the workpiece. As the end mill rotates, different blade combinations engage the material in a periodic sequence, distributing the mechanical stress and wear across all blades over time, thereby extending service life while maintaining cutting performance.
3Temperature
If coolant holes are made open to tip flank faces of bottom blades, then coolant supply is improved, but chip discharge performance remains impaired due to long bottom blades
Solution Approach 1:
Coolant holes are segmented and distributed to serve different bottom blades individually. Each coolant hole is positioned to supply coolant to specific long, middle, or short bottom blades based on their chip discharge requirements. This segmented coolant distribution ensures that each blade receives adequate cooling while the varied blade lengths maintain effective chip evacuation paths.
4Device complexity
If the number of coolant holes equals the number of bottom blades, then coolant distribution is simplified, but effective coolant supply to all blades is insufficient
Solution Approach 1:
Coolant holes are strategically positioned to provide localized coolant supply to specific bottom blades based on their individual cooling requirements. The long bottom blades, which generate more heat and chips, receive dedicated coolant supply from specific holes, while middle and short blades receive coolant from other holes. This local quality approach ensures effective coolant distribution without requiring excessive complexity in the coolant hole configuration.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enables smooth chip discharge and minimizes flank face wear of the long bottom blade, ensuring stable cutting performance over a prolonged period and preventing tool breakage.
Implementation Method 1
a first coolant hole among the coolant holes is made open to the first tip flank face connected to a backward side of the first bottom blade serving as the long bottom blade in the rotational direction of the end mill, and a second coolant hole among the coolant holes is made open to the first gash along which the first bottom blade serving as the long bottom blade is formed
Data Source
AI summary
An end mill body comprises: bottom blades formed at ridgelines where gashes and tip flank faces intersect, the gashes are formed at the tips of chip discharge grooves. At least one of the bottom blades serves as a long bottom blade that extends toward an inner peripheral side longer than the remaining bottom blades. The end mill body also has coolant holes formed between the chip discharge grooves. A coolant hole which is located between a chip discharge groove of a gash and a chip discharge groove located behind the chip discharge groove in a rotational direction is open to the tip clearance face of the long bottom blade. A coolant hole which is located between the chip discharge groove of the gash and a chip discharge groove located in front of the chip discharge groove in the rotational direction is open to the gash of the long bottom blade.