CNC milling machine is the abbreviation of digital control machine tool, is a kind of automatic machine tool with program control system. The control system can logically process the program with control code or other symbolic instructions, decode it, express it with coded numbers, and input it into the numerical control device through the information carrier. After calculation and processing, the numerical control device sends out various control signals to control the action of the machine tool, and automatically processes the parts according to the shape and size required by the drawing.
Similarities and differences between machining center and CNC milling machine:
The same as CNC milling machine, machining center is also composed of CNC system, servo system, mechanical body, hydraulic system and other parts.
But machining center is not the same as NC milling machine. The biggest difference between machining center and NC milling machine is that machining center has the function of automatic tool exchange. By installing different tools in the tool magazine, they can pass through in one clamping. In addition, the machining range of the two is different. The functions of machining center include milling workpiece, drilling workpiece, setting space, etc The machine can only mill the workpiece. The automatic tool changing device for Dongguan high-speed computer gong processing changes the processing tools on the spindle to realize various processing functions, such as drilling, boring, reaming, tapping, grooving, etc.
The spindle component of drilling and tapping center is mainly composed of spindle, bearing, spindle quasi stop installation, automatic clamping and chip removal device, which is an important part of the mechanical part of drilling and tapping center. The lubrication, cooling and sealing of the spindle components of drilling and tapping center are several problems worthy of attention in the process of machine tool use and maintenance. So, how to maintain the spindle of drilling and tapping center?
First, good lubrication effect can reduce the working temperature and prolong the service life of the bearing; therefore, attention should be paid in operation and use: grease and oil circulation lubrication is adopted at low speed; oil mist and oil air lubrication are adopted at high speed. However, when grease lubrication is used, the sealing volume of the spindle bearing is usually 10% of the bearing space volume. Do not fill it up at will. Too much grease will aggravate the spindle heating. For oil circulation lubrication, check the constant temperature oil tank of spindle lubrication every day to see whether the oil quantity is sufficient. If the oil quantity is not enough, add lubricating oil in time. At the same time, pay attention to check whether the temperature range of lubricating oil is appropriate.
In order to ensure that the spindle has good lubrication, reduce friction and heat, and take away the heat of the spindle assembly, the circulating lubrication system is usually used. The hydraulic pump is used to supply oil for lubrication, and the oil temperature controller is used to control the oil temperature of the oil tank. The spindle bearing of drilling and tapping center manufacturer adopts advanced grease sealing method for lubrication, and each grease addition can be used for 7-10 years. The new lubrication cooling method not only reduces the bearing temperature rise, but also reduces the temperature difference between the inner and outer rings of the bearing, so as to ensure the small thermal deformation of the spindle. There are two common lubrication methods for spindle. Oil air lubrication is similar to oil mist lubrication, but oil mist lubrication is to continuously supply oil mist, and oil air lubrication is to send oil mist into the bearing gap at a fixed time and quantity, which not only realizes oil mist lubrication, but also avoids the air pollution caused by too much oil mist. In order to achieve the purpose of lubrication and cooling, a large flow of constant temperature oil (3-4l / min for each bearing) is injected into the spindle bearing. Here, the oil injected with larger flow rate must be forced to drain by the drain pump instead of natural reflux. At the same time, the common large capacity and high-precision constant temperature oil tank should be used, and the oil temperature change should be controlled within ± 0.5 ℃.
Second, the cooling of the spindle components is mainly to reduce the bearing heat, invalid control of heat source.
Third, the sealing of spindle components should not only prevent dust, chips and cutting fluid from entering the spindle components, but also prevent the leakage of lubricating oil. There are non-contact seal and contact seal for spindle components. For the non-contact seal, in order to prevent leakage, it is important to ensure that the return oil can be drained as soon as possible and the oil return hole is unobstructed; for the contact seal with felt ring and oil resistant rubber seal ring, pay attention to check its aging and damage. To sum up, in the process of using and maintaining the drilling and tapping center, we must pay great attention to the lubrication, cooling and sealing of the spindle components, and do this work carefully.
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