It is very important to observe and judge the working state of the tool when machining in the CNC machining center. The precision and finish of the tool in the best condition will be well-reflected. Then, where is the main observation, the following article will tell you about it.
The reason why the processing is very laborious is that the power and torque of the spindle cannot withstand the current cutting amount. It is reasonable to re-route, reduce the depth of the knife, the depth of the groove, and the amount of trimming. If the overall machining time is less than 30 minutes, the cutting condition can also be improved by adjusting the pass speed.
Metal processing requires the addition of cooling oil. The function of the cooling system is to take away the heat of cutting and flying debris and to lubricate the processing. The coolant will cut the tropical zone, reducing the heat transferred to the tool and motor and increasing their service life. Take away the flying debris to avoid secondary cutting. Lubrication reduces cutting forces and makes machining more stable. In copper processing, the use of oily cutting fluid can improve the surface quality.
Tool wear is divided into three phases: initial wear, normal wear, and sharp wear. In the initial wear stage, the main cause of the tool wear is that the temperature of the tool is low and the optimum cutting temperature is not reached. At this time, the wear of the tool is mainly abrasive wear, and the impact of such wear on the tool is relatively large. This stage is a very dangerous stage. If it is not handled well, it may directly cause the tool to collapse. When the tool passes the initial wear period, the cutting temperature of the tool reaches a certain value. The main wear is diffusion wear, and its main effect is to cause local peeling. Therefore, the wear is relatively small and relatively slow. When it wears to a certain extent, the tool fails and it enters a period of sharp wear.
Above we said that the tool is very easy to collapse during the initial wear stage. In order to avoid the phenomenon of chipping, we must run the tool. The cutting temperature of the tool is gradually increased to a reasonable temperature. It has been experimentally verified to compare using the same processing parameters. It can be seen that the tool life has increased more than 2 times after running-in.
The method of running-in is to reduce the feed rate by half while maintaining a reasonable spindle speed. The machining time is about 5 to 10 minutes. Take small values when processing soft materials and take large values when processing hard metals.
The method to judge the serious wear of the tool is:
1) Listening to the sound of processing, a harsh call;
2) Listening to the spindle sound, the spindle has an obvious tumbling phenomenon;
3) It is felt that the vibration in the machining increases and the spindle of the machine tool has obvious vibration;
4) Look at the processing effect, the processed bottom surface is good or bad (if the starting stage is such, the depth of the knife is too deep).
We should change the tool at a time around 2/3 of the tool life limit. For example, if the tool wears severely in 60 minutes, the next time it is processed, it should start to change the tool in 40 minutes, and develop the habit of regular tool change.
After severe tool wear, the cutting force can be increased to three times normal. The cutting force has a great influence on the service life of the spindle electrode. The life and force of the spindle motor are inversely proportional to the third power. For example, in the case where the cutting force is increased by three times, processing for 10 minutes is equivalent to using the spindle 10*33=270 minutes under normal conditions.
1) Stop machining and check the current serial number of the machining.
2) Look at the broken knife, if there is a broken knife body if it is removed.
3) Analyze the cause of the broken knife. This is the most important. Why is the tool broken? We want to analyze the various factors that affect processing from the above. But the reason for the broken knife is that the force on the tool suddenly increases. Or the path problem or the tool jitter is too large, or the material has a hard block, or the spindle motor speed is not correct.
4) After analysis, replace the tool for machining. If there is no replacement path, it is necessary to advance the serial number on the original serial number. At this time, it must be noted that the feed speed will be lowered. First, the hardening of the broken knife is serious, and the second is to carry out the tool running-in.