What are the causes of poor surface roughness in machining?

Adjusting the grinding wheel stand of a milling machine is a process involving multiple steps and details. Below is a basic adjustment guide:

Preparation Phase

1. Maintain a clean workspace 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 any issues are found.
3. Prepare necessary tools, such as wrenches, screwdrivers, levels, and so on.

Adjust the position of the abrasive wheel bracket

1. According to the workpiece length and grinding requirements, adjust the position of the headstock and tailstock 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 timely during the feeding process.

Wheel Balance Adjustment

1. Utilizing a grinding wheel balancing stand to adjust and balance the grinding wheels, ensuring they do not vibrate during high-speed rotation.

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

1. After balancing adjustments, reinstall the grinding wheel stand on the grinding machine and securely tighten all relevant bolts 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 dressing tool or diamond pen to dress the abrasive wheel.
2. Ensure ample cooling liquid is poured during the trimming process to prevent the grinding wheel from overheating and damaging.
3. After trimming, reinstall the grinding wheel on the wheel stand and ensure a good contact surface between the wheel and the workpiece.

Section 5: Adjusting Workpiece Speed and Feed Rate

1. Select the appropriate workpiece speed based on the grinding wheel speed, workpiece material, diameter, and processing requirements, and achieve the desired speed through adjustment of the headstock's variable speed mechanism.
2. Adjust the feed rate of the grinding machine according to the stock removal and processing accuracy requirements.

Six: Testing and Inspection

1. Before the formal grinding, a trial grind is performed to check the adjustment effect of the abrasive wheel bracket.
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 accidental incidents.
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, the condition of the grinding wheel and workpiece should be closely monitored, and any anomalies should be addressed promptly by stopping the machine.

In summary, adjusting the grinding wheel stand of the milling machine requires meticulous operation and a strict inspection process. By adhering to the aforementioned steps and precautions, you can ensure the adjustment of the grinding wheel stand is achieved, thereby enhancing the efficiency of the grinding process and the quality of the workpiece.