Theory Of Metal Cutting

The cutting tool removes the metal from the workpiece in the form of chips. As the tool cuts into the workpiece, it creates small pieces of metal that are removed from the workpiece. These chips are typically long and thin, resembling small curls or shavings. This is the most common form in which metal is removed during machining processes. Solid blocks and powder are not typically formed during the cutting process, making them incorrect options.

The statement "Dimension accuracy is not affected in metal removal process" is false. During the metal removal process, such as machining or grinding, there is always a possibility of dimensional inaccuracies. Factors like tool wear, machine vibrations, and thermal expansion can all contribute to deviations from the desired dimensions. Therefore, it is important to carefully monitor and control these variables to ensure dimensional accuracy in the metal removal process.

When machining brittle materials, such as ceramics or certain types of metals, the formation of continuous chips is not possible due to the nature of the material. Instead, the chips that form are discontinuous, meaning they break into smaller pieces during the machining process. This is because brittle materials have low ductility and tend to fracture easily. Therefore, the correct answer is discontinuous chips.

The shear angle refers to the angle between the direction of the cutting force and the direction of the shear plane. It represents the amount of deformation and material removal that occurs during the cutting process. In the given diagram, the angle Φ represents the shear angle, indicating the magnitude of the shear forces acting on the material being cut.

The cutting speed predominantly affects the cutting temperature. This is because the cutting speed determines the rate at which heat is generated during the cutting process. A higher cutting speed leads to more friction between the cutting tool and the workpiece, resulting in increased heat generation. Therefore, the cutting temperature is primarily influenced by the cutting speed rather than the depth of cut or feed rate.

The angle between the side cutting edge and the end cutting edge is known as the nose angle. This angle determines the efficiency and effectiveness of the cutting tool in terms of its ability to penetrate the material being cut. A smaller nose angle allows for a sharper cutting edge, which is ideal for softer materials, while a larger nose angle is better suited for tougher materials.

The correct answer states that the forces required for metal cutting operation increase with both an increase in the feed of the tool and an increase in the depth of cut. This means that as the tool moves faster and cuts deeper into the material, more force is needed to overcome the resistance and remove the metal. This is because a larger feed and depth of cut result in a larger area of material being removed, requiring more force to achieve the desired cutting action.

Continuous chips are formed during metal cutting operation due to a combination of factors. Ductile work materials, which have the ability to deform plastically without fracturing, contribute to the formation of continuous chips. Additionally, a large rake angle, which is the angle between the cutting tool and the workpiece, promotes the formation of continuous chips. Finally, high cutting speed also plays a role in the formation of continuous chips. Therefore, all of the above factors contribute to the formation of continuous chips during metal cutting operations.

Both milling cutter and broaching tool are examples of multi-point cutting tools. A milling cutter is a rotating tool with multiple cutting edges, used in milling machines to remove material from a workpiece. On the other hand, a broaching tool is a linear cutting tool with multiple teeth, used to create precision holes or slots in a workpiece. Both tools have multiple cutting edges that enable them to perform multiple cutting operations simultaneously, making them multi-point cutting tools.

In metal cutting operations, the maximum heat is generated in the shear zone. The shear zone is the region where the actual cutting of the metal takes place. As the tool comes into contact with the workpiece, it exerts pressure and causes deformation in the shear zone. This deformation generates heat due to the friction between the tool and the workpiece. Therefore, the shear zone is the primary location where the majority of the heat is generated during metal cutting.