Rake angle is a cutting edge angle that has large effects on cutting resistance, chip disposal, cutting temperature and tool life. Increasing rake angle in the positive (+) direction improves sharpness. Increasing rake angle by 1° in the positive (+) direction decreases cutting power by about 1%.
What is the function of rake angle?
The rake angle (γ) is the angle between the rake surface and the reference plane (πR) or perpendicular surface of the workpiece. Rake angle is the most important factor while designing a cutting tool. It is provided so that chips from the workpiece can flow easily and also it provides a smoother machining operation.
What is the effect of rake angle on chip formation?
With the increased in positive rake angle, the cutting forces are decreased which means that less force/power is required. The results also suggest that the rake angles and the material property influence the flow of chip.
What is rake angle in cutting tool?
Rake angle is a parameter used in various cutting and machining processes, describing the angle of the cutting face relative to the work . ... Positive rake: A tool has a positive rake when the face of the cutting tool slopes away from the cutting edge at inner side.
What is shear angle?
The shear angle a refers to the contact point between the lower shear blade and the tangent of arc upper shear blade . ... The shear angle is defined as the degree of angle that changes at peak frictional force and at the commencement of the experiment.
What is the main reason for poor surface finish?
From the above equation nose radius, cutting – edge angles and feed rate have an influence on the surface finish. In turning operation the surface finish can be improved by decreasing feed and increasing nose radius. Confusion Point: Cutting speed is the most important factor in tool life and not in surface finish.
What happens when we increase or decrease rake angle and clearance angles?
Based on the simulation results, it can be concluded that: a. Increasing the rake angle in positive section caused the decrease of the cutting force . ... Smaller clearance angles caused more the contact area and friction between the clearance face and the work piece, this also increased the temperature on cutting edge.
What is positive and negative rake angle?
Rake angle is considered as positive when sum of wedge angle and flank angle is less than 90° . Rake angle is considered as negative when sum of wedge angle and flank angle is greater than 90°. Positive rake offers a thin wedge. Negative rake makes wedge thicker.
Why clearance angle is important?
It is one crucial angle that determines strength of tool tip, cutting force, power consumption, shear deformation , and also machinability. On the other hand, clearance angle is the angle of inclination of the flank surface of cutter from velocity vector and measured on another plane.
What is tool angle?
1 : the angle included between the top and front faces of a cutting tool . 2 : an angle used to designate the form of the cutting edge of a tool — compare clearance sense 2e, cutting angle, rake entry 6 sense 3.
What is true rake angle?
[′trü ′rāk] (mechanical engineering) The angle, measured in degrees , between a plane containing a tooth face and the axial plane through the tooth point in the direction of chip flow.
Why rake angle is provided in a cutting tool?
Rake surface of the cutting tool is the only chip flowing surface and orientation of this rake surface is indicated by rake angles. Thus rake angle is crucial factor to judge machining action . ... This value determines cutting force and power requirement, life of the cutting tool, chip deviation, etc.
What do you mean by back rake angle?
Back Rake: The back rake is the inclination of the face toward or away from the end or the end cutting edge of the tool . When the inclination is away from the end cutting edge, as shown in figure below. ... If the inclination is downward toward the end cutting edge the back rake is negative.
What is called shearing?
Shearing, also known as die cutting , is a process which cuts stock without the formation of chips or the use of burning or melting. Strictly speaking, if the cutting blades are straight the process is called shearing; if the cutting blades are curved then they are shearing-type operations.
How do you calculate shear angle?
In a chip formation process, the shear plane angle is the angle between the horizontal plane and the shear plane. It is calculated by this equation: Tan angle is equal to chip ratio cosine rake angle divided by 1 minus chip ratio sine rake angle.
What is angle of shearing resistance?
The angle of shearing resistance is known as a component of the shear strength of the soils which is basically frictional material and composed of individual particles. The shear strength is described by Mohr–Coulomb failure criterion adopted as widely accepted approach among the geotechnical engineers.
