Rotary Cutting Tool Rake Face for Chip Control in Brittle Machining
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Solution Overview
Problem
Cutting hard, brittle materials with conventional tools results in fine chips that cause edge chipping, wear, and increased machining time, leading to reduced tool lifespan and efficiency.
Innovation Solution
A rotary cutting tool with a diamond film-coated tip and a concavely inclined rake face, featuring a level-difference surface that separates from the cutting edge, controls chip size and reduces edge chipping by curling and dividing chips effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the feed amount per cutting edge is increased to enlarge discharged chips, then chip size increases, but brittle fractures easily occur and edge chipping is suppressed poorly
Solution Approach 1:
The invention divides chips into multiple segments using a chip breaker element and grooves on the rake face. This segmentation transforms continuous chips into smaller, manageable pieces that can be discharged without causing edge chipping or tool damage, while still allowing increased feed rates for higher productivity.
Solution Approach 2:
The chip breaker element acts as an intermediary between the cutting edge and the chip discharge path. It intercepts chips immediately after formation and breaks them into controlled sizes before discharge, mediating the conflict between chip size enlargement and edge chipping suppression.
2Duration of action of stationary object
If a hard film with some degree of thickness is formed on the tool surface, then tool lifespan extends, but roundness is formed on the edge tip, sharpness decreases, and cutting resistance increases
Solution Approach 1:
The invention applies different surface qualities to different regions of the tool. The cutting edge maintains a polished, sharp surface for low cutting resistance, while the rake face has a hard film coating for wear protection. This local differentiation resolves the conflict between edge sharpness and tool lifespan.
Solution Approach 2:
The chip breaker element is positioned to act on chips before they can cause damage to the tool or workpiece. By breaking chips preliminarily, the invention prevents edge chipping and tool damage that would otherwise occur with larger chips, allowing the use of thicker hard films without compromising cutting performance.
3Productivity
If the rotational speed is increased to improve machining efficiency, then productivity increases, but wear of the cutting edge is easily promoted
Solution Approach 1:
The continuous hard film coating on the rake face provides ongoing protection against wear during high-speed machining. Combined with the chip breaker that continuously segments chips, the system maintains effective cutting action and wear resistance even at increased rotational speeds, enabling sustained high productivity.
4Productivity
If chips are increased in size to reduce number of chips, then chip discharge problems improve, but the cutting tool or workpiece could be damaged by biting into chips during cutting
Solution Approach 1:
The chip breaker element and grooves segment chips into controlled sizes that are large enough to reduce chip count and improve discharge efficiency, but small enough to prevent tool or workpiece damage from chip biting. This segmentation resolves the contradiction between discharge efficiency and damage prevention.
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
The tool extends tool service life, improves machining efficiency, and minimizes damage to the cutting tool and workpiece by controlling chip size and reducing edge chipping during the cutting of hard, brittle materials.
Implementation Method 1
a diamond film 3 coated onto a tip end section of a tool body 1
Implementation Method 2
a rake face 6 is concavely provided in a cutting edge-side chip discharge groove formation surface 4 constituting the chip discharge groove 2 of the tool body 1, from a cutting edge 5 and along the cutting edge 5
Data Source
AI summary
It is an object of the present invention to provide a rotary cutting tool that can divide chips at an appropriate size, suppress the incidence of edge chipping and damage attributed to chips to the cutting tool and a workpiece, extend the tool service life with regard to the machining of hard, brittle materials, and improve machining efficiency. The rotary cutting tool includes a hard coat film 3 coated onto a tip end section of a tool body 1 having a chip discharge groove 2. A rake face 6 is concavely provided in a cutting edge-side chip discharge groove formation surface 4 constituting the chip discharge groove 2 of the tool body 1, from a cutting edge 5 and along the cutting edge 5.