The importance of CNC drilling machines and CNC milling machines
CNC drilling machines and CNC milling machines are an important equipment in circuit board processing. The equipment is expensive. The selection of CNC machine tools is important not only for operation, process setting and maintenance, but also for the quality of the products produced.
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As a craftsman for pure technical and operational considerations, the selection criteria for CNC machine tools generally start from the following aspects: 1. The rigidity and stability of the machine table: In order to make the machine have sufficient stability and rigidity to avoid vibration, many manufacturers Marble is used as the material of the bed. Some Japanese manufacturers use steel as the bed. Because the deformation of steel at different temperatures is larger than that of marble, it is unstable. Manufacturers will use compensation in software to eliminate the loss of precision caused by deformation. .
At present, most manufacturers use natural marble or artificial marble as the bed. It is recommended to use marble bed equipment. The marble is usually cleaned with detergent and water, and alcohol is not available. After wiping, dry with a dry cloth and wait until the water has completely evaporated before working.
2. Rotation speed and stability of the shaft:
At present, there are two types of shafts for rolling bearings with a maximum speed of 80,000 rpm and the other for air bearing speeds up to 120,000 rpm. If the milling machine should adopt rolling bearing, because its longitudinal bearing is better than air bearing, its drilling chuck is also the focus of procurement. Some drilling chucks are not easy to replace and maintain, and some drilling chucks wear quickly become consumables. Replacement costs are expensive, and some require daily maintenance to waste time.
The presser foot of the rotating shaft is also another one, and its life and unreasonable design can cause great troubles. For example, there is no seal between the shaft and the presser foot, which causes the vacuum cleaner to have a large power, which causes waste of the vacuum cleaner purchase or central vacuuming power. It is wasteful and may cause bad chip evacuation in the hole of the board.
3. Table movement accuracy and displacement repeatability:
This is the most important point when choosing. It can't be seen through pictures or ordinary operation. It can only be certified after being purchased. The current equipment can meet the design standard when it leaves the factory. The key is to run one to two years later. The accuracy of the machine is very stable, and the machine tools produced in Europe are better.
4. Feed rate of X, Y and Z axes:
The feed rate is currently a general-purpose screw stepper motor with a speed of 25 meters per minute, while the new product has adopted a servo motor. The high feed rate can increase the productivity by 20%-40%, and the Z-axis speed is affected by the drill bit and The influence of the material being drilled on the feed rate has little effect on production efficiency.
5. Movement and fixture of the countertop: The movement of the countertop is carried out by many guide rails
6. Maximum processing size: The maximum processing size is purchased according to the needs. At present, most of the machine tools can meet your needs, except for some single-axis or double-axis machines for samples or test fixtures.
7. Operating system and control system:
Now many machine tools use the common Windows operating system interface is very friendly, and some also use Chinese, it is easier to get started learning and operation, but its shortcomings will be less stable and difficult to manage, and some use industrial systems or Unix systems. The advantage of this kind of system is that it has good stability, is not easy to malfunction, and is convenient to manage. But the operation interface is in English, the operation is slightly slower. The latter is recommended from the standpoint of process and equipment maintenance.
8. Tool management system:
In the past, there were only 8 tool holders, and most of the CNC machine tools can be placed with hundreds of drill bits. Some systems also have automatic diagnosis of broken drills, diameter detection length and radial runout system. The item to be noted when the type is concerned is that most of the drill bits of the CNC bed are placed at the front end of the table. This design method has a disadvantage. If the circuit board processed during operation jumps out due to fixing problems, it is easy to break all the drill bits. Includes drill fixtures. Some drill fixtures are designed to be placed on top of the machine. For example, some Swiss-made machines will not cause this problem. The sensitivity of the detection mechanism is too high and too low.
9. Purchase of the light rule system:
At present, most of the measurement systems of CNC machine tools use the light ruler as the position and accuracy measurement feedback system, and also use the magnetic ruler. The system stability and resolution of the light ruler are high, because the read head of the light ruler has no contact with the ruler. Friction, so the life is very long, but usually keep the equipment clean to minimize dust pollution.
10. Vacuum system:
If the company does not have a central vacuum system and uses a common industrial vacuum cleaner as a matching device, it should be noted that the vacuum cleaner should have a large power, preferably 30-50% larger than the power required by the original design, due to the plugging power of the filter during actual use. It will drop a lot. Secondly, the vacuum cleaner's powder bag should have sufficient capacity. If the capacity is too small, the workers will often stop working to deal with the dust and affect the production efficiency.
11. Protection system:
Refers to the protection software of the software and equipment of the equipment to prevent accidental accidents and accidents caused by the equipment itself, such as grating protection infrared protection air switch, etc., such as infrared protection, etc., which need to be designed reasonably, some protection designs are not for maintenance. very convenient. So we must weigh all.
Relatively recommended to purchase European-made equipment such as Switzerland and Germany, although the price may be slightly higher than the Japanese machine tools, but the value for money, and the future maintenance costs are more reasonable and less problems, long use. As a personal point of view, a person or country that cannot be recognized even in history, how can a promise of a small contract that has been signed into a history be guaranteed?