1. Investigation of the effect of rake angle and approaching angle on main cutting force and tool tip temperature International Journal of Machine Tools & Manufacture Authors: HaciSaglam FarukUnsacar SuleymanYaldiz Date of Publication: May 5, 2005 Presenter: Matt Maxfield Date: October 7, 2009
2. 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
3. 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
5. How does this relate to us? Learning about machining processes Learning 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
6. Design and Parameters Tested practically under workshop conditions Each test conducted with sharp uncoated carbide tool insert Constants 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
7. 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
8. Method of Testing Test conducted under dry conditions Full factorial design of experiment Experimental results compared with calculated results
9. 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
10. Experimental Results The effect of approaching angle on main cutting force and tool tip temperature
13. 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
14. 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°
15. 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
