Which of the following machine is based upon the principle that the rotating edge of the tool exerts a large force on the workpiece and holes are being created in the workpiece? The material is removed from the workpiece by the shearing and extrusion process.
Drilling machine
Drilling Machine: Introduction to Hole Creation
Manufacturing involves various processes to shape raw materials into finished products. One fundamental operation is the creation of holes in a workpiece. This specific task requires a machine that can effectively remove material to form precise cylindrical openings.
Drilling Machine: Core Principle and Operation
The machine described in the question, where a rotating edge of the tool exerts a large force on the workpiece and holes are being created, directly points to a drilling machine. This machine is purpose-built for this precise function.
- Rotating Edge of the Tool: In a drilling machine, the primary cutting tool is known as a drill bit. This tool is designed with helical flutes and sharp cutting edges at its tip. The machine's spindle rotates the drill bit at high speeds.
- Exerting a Large Force: As the rotating drill bit is advanced into the workpiece, a significant axial feed force is applied. This force, combined with the rotational motion, enables the drill bit's cutting edges to penetrate and cut into the material.
- Holes are Being Created: The continuous cutting action and penetration of the drill bit result in the formation of cylindrical holes in the workpiece. The diameter of the hole corresponds to the diameter of the drill bit used.
Material Removal: Shearing and Extrusion Process
The question highlights that the material is removed from the workpiece by the shearing and extrusion process. This describes how the drill bit effectively separates and displaces material to form the hole.
- Shearing: As the cutting edges of the drill bit advance, they apply pressure that causes the material directly in front of them to deform plastically and then shear off. This process generates chips, which are then evacuated along the flutes of the drill bit. Most of the material removal in drilling occurs through this shearing action, where layers of material are sliced away.
- Extrusion: At the very center of the hole, beneath the chisel edge of the drill bit (the non-cutting part at the tip), the material is not primarily sheared. Instead, it undergoes intense compression and plastic deformation, effectively being pushed or "extruded" radially outwards and then sheared by the main cutting edges. This combination of shearing and extrusion ensures efficient material removal even from the center of the cutting zone.
Machining Processes: Contrasting Other Machines
To further understand why the drilling machine is the correct fit, let's examine the principles of other common machine types:
| Machine Type | Primary Function & Tool Motion | Material Removal Process | Relevance to Question Criteria |
|---|---|---|---|
| Drilling machine | Creates cylindrical holes; rotating tool (drill bit) moves axially into a stationary workpiece. | Primarily shearing, with some extrusion at the center. | Perfectly matches all criteria: rotating edge of the tool exerts a large force, holes are being created, material is removed by shearing and extrusion. |
| Shaper machine | Creates flat or contoured surfaces, grooves; uses a single-point cutting tool in a linear reciprocating motion against a stationary workpiece. | Chip formation through linear shearing. | Does not use a rotating edge to create holes; its motion is linear. |
| Lathe machine | Produces cylindrical or conical shapes; the workpiece rotates while a stationary single-point cutting tool removes material. | Continuous chip formation through shearing and plastic deformation. | The workpiece rotates, not the cutting tool's edge in the manner described for creating holes. While drilling can be performed on a lathe, the primary principle described for the tool's action is not a lathe's defining characteristic. |
| Milling machine | Creates flat surfaces, slots, grooves, and complex contours; uses a multi-point rotating tool (milling cutter) that moves relative to the workpiece. | Intermittent cutting and shearing by multiple teeth. | While it uses a rotating tool, its main function is not typically focused on creating deep cylindrical holes through the specific shearing and extrusion process in the same dedicated manner as a drilling machine. Milling cutters remove material in a different kinematic manner. |
Hole Creation: Summary of Drilling Machine Advantages
In conclusion, the machine that operates on the principle where a rotating edge of the tool exerts a large force on the workpiece, resulting in holes being created through the shearing and extrusion process for material removal, is the drilling machine. Its design and operational mechanics are specifically tailored for efficient and precise hole-making.
Important Questions from Drilling and Reaming
The angle formed at the web of a twist drill between the chisel edge and the cutting lip is known as the _______.
The point angle of a drill bit is ______.
Which of the following is a cutting tool used in the drill machine?
Which of the following tools is used for making holes in wood, metal and concrete?
Which of the following drilling machines is used for the purpose of drilling several holes simultaneously?
