How to reduce tool wear through CNC turning parameters

To reduce tool wear through the optimization of CNC turning parameters, it is necessary to start from core dimensions such as cutting force control, heat management, and tool life balance, and dynamically adjust the parameters in combination with material properties and processing scenarios. The following are the specific strategies and key points of implementation:

First, precise control of cutting parameters

Dynamic adjustment of cutting speed (Vc)

Material compatibility principle:

When processing plastic materials such as low-carbon steel and aluminum alloy, appropriately increasing the cutting speed (such as 80-120 m/min) can reduce the friction time between the chip and the tool and lower the adhesive wear.

When processing high-hardness materials (such as quenched steel), the cutting speed should be reduced (such as 30-60 m/min) to avoid tool chipping or hot cracking due to excessive cutting force.

Critical point of tool wear:

When the cutting speed exceeds the heat resistance limit of the tool material, the wear rate will increase sharply. For instance, when the speed of hard alloy cutting tools exceeds 150 m/min, oxidative wear and diffusion wear will significantly intensify.

Optimal selection of feed rate (f)

The relationship between feed rate and wear:

Excessive feed rate will lead to a sudden increase in cutting force and accelerate the wear of the rear tool face. If the feed rate is too small, it may cause the cutting edge of the tool to rub against the surface of the workpiece due to the thin chips.

Recommended scope:

During finish machining, the feed rate should be controlled at 0.05-0.15 mm/r. During rough machining, it can be appropriately increased to 0.2-0.3 mm/r, but adjustments should be made in combination with the strength of the cutting tool and the rigidity of the machine tool.

The stratification strategy of back cut volume (ap)

Layer-by-layer processing of workpieces with large allowances

For workpieces with a allowance exceeding 3 mm, using layer-by-layer turning (0.5-1.5 mm per layer) can significantly reduce the fluctuation of cutting force and minimize the impact wear of the tool.

Careful control of thin-walled parts processing

When processing thin-walled parts, the depth of cut must be strictly controlled within 0.1- 0.3mm to avoid uneven force on the tool due to workpiece deformation.

Second, the collaborative optimization of cutting parameters

Optimization strategy:

On the premise of ensuring processing efficiency, give priority to reducing the depth of cut and feed rate, and appropriately increase the cutting speed to minimize the cutting force and tool wear.

The application of constant linear speed control (G96 command)

Cutting optimization of workpieces with variable diameters

When processing workpieces with variable diameters such as conical surfaces and arcs, enabling constant linear speed control can ensure a constant cutting speed and avoid fluctuations in cutting force caused by changes in diameter.

Dual improvement of surface quality and tool life:

Constant linear speed control can make the chip morphology more stable and reduce tool wear caused by chip entanglement.

Third, real-time monitoring and parameter adjustment of tool wear

Monitoring methods for tool wear

Sound and vibration monitoring

When the wear of the cutting tool intensifies, the cutting sound will become sharp and the vibration frequency will increase. It can be monitored in real time through acoustic emission sensors or vibration sensors.

Cutting force monitoring

Install a force gauge to monitor the changes in cutting force. When the cutting force suddenly increases, it may indicate that the tool has worn out or chipped.

Parameter adjustment based on wear state

Initial wear stage:

In the early stage of tool wear, the fluctuation of cutting force is relatively small, and the original parameters can be maintained for processing.

Normal wear stage:

When the rear face wear width (VB value) reaches 0.1-0.2 mm, appropriately reduce the cutting speed by 5%-10% and decrease the feed rate by 10%-15%.

Rapid wear stage:

When the VB value exceeds 0.3mm, the machine should be stopped immediately to replace the cutting tools to avoid scrapping the workpiece or damaging the machine tool due to tool failure.

Fourth, parameter optimization under special working conditions

Parameter adjustment of difficult-to-machine materials

Stainless steel and titanium alloy

This type of material has poor thermal conductivity and is prone to generating high temperatures during cutting. The cutting speed needs to be reduced by 30%-50%, and high-pressure coolant (pressure ≥5 MPa) should be adopted for enhanced cooling.

Superalloy

The cutting speed should be controlled at 20-40 m/min, the feed rate 0.05-0.1 mm/r, the depth of cut 0.1-0.3 mm, and sulfur-containing extreme pressure cutting oil should be used.

Parameter optimization of intermittent cutting

Mitigation of impact loads

When processing discontinuous surfaces such as keyways and splines, the cutting speed should be reduced by 20% to 30%, and the feed rate should be decreased by 20% to reduce the impact load on the tool.

Strengthening selection of tool materials:

Give priority to using tool materials with good toughness (such as cobalt-containing high-speed steel or coated cemented carbide), and increase the rake and relief angles of the tool to reduce the cutting force.

Fifth, Summary of key implementation points

Prioritize reducing the cutting force:

By reducing the depth of cut and feed rate, the tool wear rate can be significantly decreased.

Reasonably match the cutting speed:

Select an appropriate cutting speed based on the hardness of the material and the material of the tool, avoiding either too high or too low.

Real-time monitoring and dynamic adjustment

Monitor the tool wear status through signals such as sound, vibration and cutting force, and adjust the parameters in a timely manner.

Strengthen cooling and lubrication:

High-pressure coolant can effectively lower the cutting temperature and reduce the thermal wear of the tool.

Through the above parameter optimization strategy, it is possible to significantly extend the tool life and reduce the production cost while ensuring the processing efficiency.