A Comprehensive Guide to the Basics of Machining centers 2

Why is passivation treatment necessary for machining center tools?

Why is passivation treatment necessary for CNC tools? It's not the case that the faster the better. In fact, tool blunting is not what people literally understand, but rather a way to increase the service life of tools. Improve the quality of cutting tools through processes such as leveling, polishing and deburring. This is actually a normal process for the cutting tool after fine grinding and before coating.

▲ Comparison of tool blunting

Before the cutting tool is finished, it will be ground by a grinding wheel, but the grinding process will cause microscopic notches of varying degrees. While the machining center is performing high-speed cutting, micro-notches can easily expand, accelerating the wear and damage of the cutting tools. In modern cutting technology, there are strict requirements for the stability and precision of cutting tools. Therefore, CNC cutting tools must undergo passivation treatment of the cutting edge before coating to ensure the firmness and service life of the coating. The benefits of tool blunting include:

1. Resist physical wear of cutting tools

During the cutting process, the surface of the cutting tool is gradually worn by the workpiece, and the cutting edge is also prone to plastic deformation under high temperature and high pressure during the cutting process. The passivation treatment of cutting tools can help enhance their rigidity and prevent them from losing their cutting performance prematurely.

2. Maintain the smoothness of the workpiece

Burrs on the cutting edge of the tool can cause tool wear and make the surface of the processed workpiece rough. After passivation treatment, the cutting edge of the tool will become very smooth, the phenomenon of chipping will be reduced accordingly, and the surface finish of the workpiece will also be improved.

3. Facilitate chip removal in the groove

Polishing the grooves of cutting tools can enhance surface quality and chip removal performance. The flatter and smoother the groove surface is, the better the chip removal will be, and a more continuous cutting process can be achieved. After the CNC tools of the machining center undergo passivation and polishing, many small holes will be left on the surface. During processing, these small holes can absorb more cutting fluid, greatly reducing the heat generated during cutting and significantly increasing the cutting speed.

How does a machining center reduce the surface roughness of workpieces?

Rough surface of parts is one of the common problems of CNC machining centers, which directly reflects the processing quality. To control the surface roughness of parts during processing, we must first conduct an in-depth analysis of the causes of surface roughness, mainly including: tool marks caused during the milling process; Thermal deformation or plastic deformation caused during cutting separation; Friction between the cutting tool and the machined surface.

When selecting the surface roughness of the workpiece, it should not only meet the functional requirements of the part surface but also take into account economic rationality. Under the premise of meeting the cutting function, a larger surface roughness reference value should be selected as much as possible to reduce production costs. As the executor of the cutting machining center, the cutting tool should pay attention to daily maintenance and timely grinding to avoid the surface roughness being unqualified due to the tool being too blunt.

What should be done after the machining center finishes the work?

The traditional machine tool processing regulations for machining centers are generally similar. The most significant difference lies in that a machining center completes all cutting processes through a single clamping and continuous automatic processing. Therefore, after completing CNC processing, a machining center needs to carry out some "follow-up work".

1. Carry out cleaning treatment. After the machining center completes the cutting task, the chips should be removed in time and the machine tool wiped. Keep the machine tool and the environment clean.

2. For the inspection and replacement of accessories, it is first necessary to pay attention to checking the oil rubbing plate on the guide rail. If it is worn, it should be replaced in time. Check the condition of the lubricating oil and coolant. If they become cloudy, replace them in time. If the water level is lower than the marked level, add more.

3. The shutdown procedure should be standardized. The power on the machine tool operation panel and the main power should be turned off in sequence. Under the absence of special circumstances and requirements, the principle of returning to zero first, manual operation, point operation, and automatic operation should be followed. The operation of the machining center should also start at low speed, then medium speed, and finally high speed. The operation time at low and medium speeds must be no less than 2 to 3 minutes. Only after there are no abnormal conditions can the work start.

4. Standardize the operation. Do not strike, correct or modify the workpiece on the chuck or at the center. Only after confirming that the workpiece and the tool are clamped tightly can the next operation be carried out. The fuses and safety protection devices on machine tools must not be disassembled or moved at will. The most efficient processing is actually safe processing. As an efficient processing equipment, the operation of the machining center when it is shut down must be reasonable and standardized. This not only maintains the current completed process but also prepares for the next start-up.