How to monitor cutting parameters during drilling and milling machine processing?

During the drilling and milling machine processing, the monitoring of cutting parameters is a key link to ensure processing quality, equipment safety and production efficiency. By real-time monitoring of the cutting status, abnormalities can be detected promptly and process parameters adjusted to prevent tool damage, workpiece scrapping or machine overload.

I. Core Cutting Parameters and Their Monitoring Significance

In drilling and milling operations, the following key parameters mainly need to be monitored:

The spindle speed and feed rate ‌

The spindle speed (r/min) and feed rate (mm/min) directly affect the material removal rate and surface quality. If it is too high, it will cause the cutting tool to overheat and wear out; if it is too low, it will affect efficiency. It can be directly read through the numerical control system and compared and corrected in combination with the material properties.

Cutting force and spindle load ‌

The variation of cutting force reflects the force state of the cutting tool. When the cutting tool wears out or there are hard spots on the workpiece, the cutting force will increase significantly. The DNC system can collect the load data of the spindle in real time. Once it abnormally rises, it will issue a warning and prompt you to check the tool or adjust the parameters.

Cutting temperature and vibration ‌

High temperatures accelerate the oxidation and wear of cutting tools, while vibration may cause vibration marks on the machined surface or even tool breakage. Monitoring the temperature at the tool tip with an infrared thermometer or thermocouple and detecting the vibration amplitude with an acceleration sensor can help determine the processing stability.

Sound and noise characteristics ‌

The normal cutting sound is smooth and continuous. If there is a knocking sound or a sharp noise, it often indicates that the tool is loose, worn or about to break. Acoustic emission (AE) sensors can capture weak stress wave signals, achieve early fault warning, and have high sensitivity and moderate cost.

Cooling and lubrication state ‌

The flow rate, pressure and spray position of the cutting fluid affect the heat dissipation and chip removal effect. Monitoring the operation status of the cooling system to ensure that the processing area is always under effective cooling conditions is particularly crucial in deep hole drilling.

Ⅱ. Common Monitoring Methods and Technical Means

Modern drilling and milling machines mostly adopt an integrated solution of "sensors + control systems" to achieve automated monitoring

Multi-functional data acquisition system ‌ : synchronously acquires multiple signals such as force, temperature, vibration, and current, conducts correlation analysis, and enhances judgment accuracy.

PLC and human-machine interface (HMI) ‌ : real-time display of the operating status and alarm information of each axis, support manual intervention and parameter modification, facilitating debugging and maintenance.

Online measurement and adaptive control ‌ : Combined with laser displacement sensors or probes, it enables online detection of workpiece dimensions, and the system can automatically compensate for tool wear errors.

Power and current monitoring ‌ : Indirectly determine the tool status through changes in the main motor power. For instance, in deep hole drilling, the GKQ monitor can determine if chip removal is not smooth based on a sudden increase in power, and promptly stop the machine to clear the chips.

Ⅲ. Practical Operation Suggestions

During the rough machining stage ‌ : Focus on the cutting load, and dynamically adjust the cutting depth and feed rate according to the load table to maximize the efficiency of the machine tool.

In the finishing stage ‌ : Focus on controlling the formation of built-up edge and corner overcutting, optimize the spray Angle of cutting fluid, and avoid fluctuations in surface quality.

In mass production, ‌ : Set a tool life timer. When the preset processing time is reached, it will automatically prompt for replacement to prevent batch defects caused by tool fatigue.

Abnormal handling procedure ‌ : Once abnormal load, intensified vibration or sudden change in sound is detected, processing should be immediately suspended to check the integrity of the tool and the clamping status of the workpiece.