Which of the following wheels supports the workpiece in internal centreless grinding operation?

Explanation:

Internal Centreless Grinding Operation

Definition: Internal centreless grinding is a machining process that removes material from the internal surface of a cylindrical workpiece. Unlike traditional internal grinding, where the workpiece is held between centers, internal centreless grinding uses a unique setup where the workpiece is supported by three wheels: the pressure roller, supporting roller, and regulating wheel. This method is particularly effective for producing high-precision internal diameters in mass production environments.

Working Principle: In internal centreless grinding, the workpiece is supported by the pressure roller, supporting roller, and regulating wheel. The pressure roller applies force to the workpiece, holding it against the regulating wheel, which controls the rotation and axial movement of the workpiece. The supporting roller provides additional stability and support. The grinding wheel, which is positioned inside the workpiece, removes material from the internal surface as it rotates.

Advantages:

• High precision and accuracy in internal diameter grinding.
• Ability to grind complex internal geometries.
• Increased productivity due to continuous operation.
• Reduced setup times as the workpiece does not need to be centered.

Disadvantages:

• Requires specialized equipment and setup.
• Limited to specific types of workpieces and materials.
• Higher initial investment compared to traditional internal grinding methods.

Applications: Internal centreless grinding is commonly used in the manufacturing of precision components such as bearings, bushings, and hydraulic cylinders. It is particularly effective for high-volume production environments where consistent quality and tight tolerances are required.

Analysis of Other Options:

Option 2: Only pressure roller

This option is incorrect because the pressure roller alone cannot provide the necessary support and stability for the workpiece during the grinding operation. The pressure roller's primary function is to apply force to the workpiece, but without the supporting and regulating wheels, the workpiece would not be held in the correct position or rotated consistently.

Option 3: Only supporting roller

This option is also incorrect as the supporting roller alone cannot maintain the workpiece's position or control its rotation. The supporting roller provides stability, but it works in conjunction with the pressure roller and regulating wheel to ensure the workpiece is properly supported and rotated during the grinding process.

Option 4: Only regulating wheel

The regulating wheel is responsible for controlling the workpiece's rotation and axial movement, but it cannot support the workpiece on its own. Without the pressure roller and supporting roller, the workpiece would not be held in place or maintained in the correct position for effective grinding.