What are the causes of poor surface roughness in milling and grinding processing?

Adjusting the abrasive wheel bracket of a milling machine is a process involving multiple steps and details. Here is a basic adjustment guide:

Preparation Phase

1. Maintain a clean work area free of clutter to avoid interference during the adjustment process.
2. Inspect the grinding wheel stand and its accessories for any damage; replace or repair promptly if necessary.
3. Prepare necessary tools, such as wrenches, screwdrivers, levels, etc.

Adjust the position of the abrasive wheel bracket

1. According to the workpiece length and grinding requirements, adjust the headstock and tailstock positions to center the workpiece on the worktable, and ensure the workpiece's rotational axis is parallel to the longitudinal movement direction of the worktable.
2. Adjust the position of the reversing stop on the lathe worktable's front side to ensure the table can reverse in time during the feeding process.

Wheel Balance Adjustment

1. Utilizing a grinding wheel balancer for balancing adjustments ensures that the wheel operates without vibration during high-speed rotation.

• The abrasive wheel is mounted on a balanced spindle and placed flat on the balancing guide rail of the abrasive wheel balancing bracket.
• Observe the vibration of the grinding wheel; if it's unbalanced, adjust the position of the balancing weight until the wheel can remain stationary in any position.

1. After balancing adjustments, reinstall the grinding wheel stand on the grinder and securely tighten all screws and nuts.

Grinding Wheel Trimming and Installation

1. Select the appropriate dressing amount based on the grinding requirements (rough or fine grinding) and use a diamond dresser or diamond pen to dress the abrasive wheel.
2. Ensure sufficient coolant is applied during the trimming process to prevent the grinding wheel from overheating and damaging.
3. After the trimming is complete, reinstall the grinding wheel on the wheel stand and ensure the contact surface between the wheel and the workpiece is good.

Five: Adjust workpiece speed and feed rate

1. Select the appropriate workpiece speed based on the abrasive wheel's speed, workpiece material, diameter, and processing requirements, and obtain the required speed by adjusting the headstock's speed-changing mechanism.
2. Adjust the feed rate of the grinding machine based on the stock removal and machining accuracy requirements.

Six: Trial Grinding and Testing

1. Prior to the formal grinding, a trial grind is conducted to check the adjustment effect of the abrasive wheel stand.
2. Utilize micrometers and calipers to inspect the size and shape accuracy of workpieces.
3. If requirements are not met, the abrasive wheel stand and grinding parameters should be readjusted.

Section 7: Safety and Precautions

1. During the adjustment process, strict adherence to safety operating procedures is essential to prevent any accidents.
2. After adjustments are made, a check should be performed to ensure that all components are securely fastened and move freely.
3. During the grinding process, close attention should be paid to the condition of the grinding wheel and workpiece, and any anomalies should be addressed promptly by shutting down the machine.

In summary, adjusting the grinding wheel bracket of the milling machine requires meticulous operations and a stringent inspection process. By adhering to the aforementioned steps and precautions, you can ensure the bracket adjustment is achieved to the state, thereby enhancing the grinding efficiency and processing quality.