Causes and solutions for abnormal cylindrical grinding

Release Date:2023-09-18 14:48

Cylindrical grinding is a critical step in production on various product production lines, done incorrectly it can give less than desirable results. There are two primary imperfections to consider: surface roughness and dimensional accuracy. These imperfections can arise from improper operations, mechanical issues, or recurring problems. Often, a combination of factors can contribute to a single flaw, necessitating a systematic review of the complete manufacturing process to identify and rectify potential causes. In the article, we outline the distinctive characteristics of these imperfections and provide a list of potential causes and possible solutions.

Chatter marks

Chatter marks are defined by parallel lines on the workpiece and are a result of vibration relative to the grinding wheel. They terminate sharply, indicating that the workpiece vibrates in relation to the wheel, causing intermittent or partial contact between the workpiece and the wheel.

Possible Causes and Solutions:

1. Excessive Depth of Cut: One of the primary causes of chatter marks is taking too large a depth of cut. This is particularly noticeable with slender workpieces. Reducing the depth of cut and ensuring stable support can help alleviate this issue.

2. Excessive Hardness of the Grinding Wheel: If immediate replacement of the wheel is not possible, alternative measures can be taken. These include increasing workpiece speed, using coarser grit for roughing, reducing wheel speed, and enhancing lubrication.

3. Inadequate Support for Long Work Pieces: For long and slender workpieces, it is crucial to use stable supports, especially during straight plunge grinding operations. When work pieces vibrate relative to the wheel, multiple supports become essential.

4. Vibration Transmission to the Grinder: External vibrations can affect the grinder's performance. A simple test involves stopping the operation and placing a cup of water on the wheel's spindle housing. Any continued motion indicates extraneous vibrations.

5. Inherent Grinder Vibration: Testing individual components of the grinder can pinpoint the source of excessive vibration. This includes the wheel spindle unit, main spindle housing, pump, and worktable during transverse grinding.

Shortwave Marks

Possible Causes and Solutions:

1. Vibration from Belts: Uneven belt thickness can lead to shortwave marks. Adjusting the tension and ensuring the proper fit of V-belts can help alleviate this issue.

2. Vibration from Other Machinery: Check for any external vibrations being transmitted to the grinder. Temporary measures may include reducing wheel speed when using fine-grit and soft-bond wheels.

3. Vibration in the Hydraulic System: Improper operation of pumps or valves in the hydraulic system can lead to vibrations. Adjusting the relief valve or addressing any specific issues in the system can mitigate this problem.

4. Vibration from Motors: Any vibration in the motors should be thoroughly examined. Ensure that the motor is securely fastened to the base and that the pulleys are balanced.

5. Vibration from Chains and Sprockets: Using larger sprockets and maintaining proper tension in chains can prevent shortwave marks. Additionally, ensuring that the number of teeth on the sprocket is appropriate for the chain's pitch is crucial.


Longwave Marks

Longwave marks resemble shortwave marks but are more commonly seen in transverse grinding. They manifest as converging lines, primarily due to an imbalanced grinding wheel.

Possible Causes and Solutions:

1. New Wheel Imbalance: When suspecting imbalance, it's advisable to remove the wheel and arbor assembly and balance it on a stand. Preliminary dressing on the grinder is essential before balancing a new wheel.

2. Failure to Turn Off Coolant: If the wheel is stopped without turning off the coolant, it can lead to wheel imbalance and surface roughness issues. Always ensure that the coolant is turned off before stopping the wheel.

3. Oil Soaking on One Side of the Wheel: A wheel with one side soaked in oil should not be used when surface finish is critical. Preventing oil contamination is essential.

4. Placing the Wheel on Damp Surfaces: Wheels placed on damp concrete surfaces may absorb moisture and lose balance during use. It's recommended to use a stand to elevate the wheel or isolate it from the ground.


Mottlemarks, similar to longwave marks, are often observed in transverse grinding. They are characterized by irregular patterns on the surface, caused primarily by an unbalanced wheel.

Possible Causes and Solutions:

1. Diamond Nib Looseness: The diamond nib should be securely fastened in its holder. Any play in the nib can cause vibration and irregularities on the workpiece surface.

2. Vibration in the Diamond Tool Holder: The diamond tool holder must not vibrate during dressing operations. Use a C-clamp or weights to stabilize the holder and suppress any vibration caused by an overly extended tool shank.

3. Uneven Cross feed of the Worktable: Uneven movement of the worktable during dressing can result in mottled marks. Ensure smooth and uniform motion of the worktable for optimal dressing results.

Burlap Finish

This defect is characterized by a surface texture resembling burlap fabric, which is undesirable in many applications.

Possible Causes and Solutions:

1. Loose Diamond Dresser: Ensure that the diamond nib is securely fastened in its holder. Any movement during dressing operations can lead to an irregular surface.

2. Vibration in the Diamond Tool Holder: The tool holder must remain stable during dressing to prevent patterns on the wheel surface. Confirm that the foot-stock type tool holder is secure and that the tool shank is properly supported.

3. Uneven Crossfeed of the Worktable: During dressing, the movement of the worktable must be uniform and smooth to achieve ideal results. Check for proper lubrication and address any issues with the hydraulic system.

Understanding the causes of these grinding imperfections is crucial for maintaining high-quality production. By identifying and addressing these issues quickly and effectively, manufacturers can ensure consistent and precise cylindrical grinding results.

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