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AUTHORS: HACI SAGLAMFARUK UNSACARSULEYMAN YALDIZ
International Journal of Machine Tools & Manufacture
Investigation of the effect of rake angle and approaching angle on main cutting
force and tool tip temperature
DATE OF PUBLICATION: MAY 5 , 2005
PRESENTER: MAT T MAXFIELDDATE: OCTOBER 7 , 2009
Function of this Paper
Compare measured and calculated results of cutting force components and temperature variation on the tool tip of various tool geometries used in machining AISI 1040 Steel
The Importance of Cutting Force & Temperature
Due to more demanding manufacturing processes and systems, the requirements for reliable technological information have increased
Cutting forces are mainly affected by cutting speed, feedrate, undeformed chip thickness, cutting tool material, tool geometry, depth of cut and tool wear
There are many empirical equations for cutting force but experimental measurements are more reliable
Predicting temperature distribution is important in determining the maximum cutting speed
References
How does this relate to us?
Learning about machining processesLearning about the effects of tool geometry
Rake face - tool’s leading edge Rake angle - slant angle of tool’s leading edge (α) Flank - following edge of cutting tool Relief angle – angle of tool’s following edge above part
surface
Design and Parameters
Tested practically under workshop conditionsEach test conducted with sharp uncoated carbide
tool insertConstants
Depth of cut Cutting speed
Variables Approach angle Rake angle
Work piece material selected to represent the major group used in industry (AISI 1040 Steel)
Full factorial design
Method of Testing
Experiments were carried out on a CNC turning machine
Main cutting force (Fc), feed force (Ff), and thrust force (Ft) were measured using a three component turning dynamometer
A radiation sensor was used for temperature measurement on the tool tip
Method of Testing
Test conducted under dry conditionsFull factorial design of experiment
Experimental results compared with calculated results
Calculating Forces and Temperatures
Main cutting force (Fc)
Ac = chip cross-sectional area
Ks = specific cutting force
Average temperature rise
Pu = friction power spent on the tool face Pu = FuVc
Fu = friction force Fu = Fc sin αr +Ff cosαr
Mc = metal removal rate
Cs = specific coefficient of heat of workpiece
Experimental Results
The effect of approaching angle on main cutting force and tool tip temperature
Experimental Results
The effect of rake angle on main cutting force and tool tip temperature
Experimental Results
The effect of feedrate on main cutting force and tool tip temperature
Correlations of Experimental vs. Calculated
Deviation of calculated cutting force components form measured values
Average deviation of main cutting force calculations for 64 experiments was 0.37%
Design Challenges
The average deviation of the temperature for 64 experiments was 42%
Due to the flowing chips some of the heat was conducted to the workpiece and an acurate tool tip measurement was not able to be made
For a reliable measurement a thermocouple should be embedded into the cutting insert
Conclusions
Increasing the rake angle over its optimum value has a negative effect on tool’s performance and accelerates tool wear which leads to an increase in cutting force
It is difficult to create a fully comprehensive model of all cutting parameters for cutting force
Feedrate = cutting force
Rake angle = cutting force
Optimum rake angle = 12°
Optimum machining at γ=0° and χ=75°
Conclusions
How does this paper help in industry? Practical in gaining a better understanding of the
effects of rake angle and approach angle on cutting force but did have some design flaws in analyzing temperature
Is there any technical advancement? It adds to the current knowledge about cutting force
variables by testing parameters not studied as frequently
What industries are most affected by this research? Machinist who work with steel Most industries