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