If you want the train to run fast, it all depends on the headstock. This metaphor is not an exaggeration when applied to CNC machine tools. It can be said that if the machine tool wants to cut fast, it all depends on the spindle belt.
It is enough to prove that the spindle is one of the very important core components of CNC machine tools. It determines the speed, cutting force and even processing efficiency of the CNC machining center.
According to the different forms, it is divided into four types: belt spindle, gear spindle, direct-drive spindle and electric spindle. The following is a detailed introduction to these four spindles.
المغزل الحزامي
The belt spindle of CNC machining center is widely used. It can be used from small to large machining centers. The speed will not exceed 8000. Its advantages are easy assembly and less vibration than gear type. The disadvantages are that the faster the speed, the greater the noise, and the belt tension is difficult to control.
محور التروس
Large and medium-sized CNC machine tools use this speed change method. Through a few pairs of gears to reduce the speed and expand the output torque to meet the requirements of the output torque characteristics of the spindle at low speed. The main advantage is powerful, and the disadvantage is large noise and vibration.
Direct-connected spindle
The direct-connected spindle speed of CNC machining center can reach 12,000 rpm. The higher the speed, the smaller the cutting force. The cutting force of the direct-connected spindle is not as good as that of the belt-type spindle, and it does not perform heavy cutting. Therefore, the machining center using the direct-connected spindle is basically mainly used to process small parts.
It is a rigid connection, and the POWER output by the motor can be fully expressed in the spindle characteristics. The mechanical efficiency is higher. When the spindle moves, the coupling plays an indispensable role. The good or bad correction of the coupling is enough to affect the spindle movement accuracy. If the coupling is not properly corrected, it will have the following effects on the spindle:
1 The temperature rise of the spindle increases sharply
2 The spindle vibrates too much
3 The spindle deflection is too large
4 Poor machining accuracy
Electric spindle
The electric spindle is the latest type of spindle. The spindle speed is very high and can reach 50,000 rpm. The higher the speed, the smaller the cutting force. Therefore, the electric spindle speed is the fastest. The internal motor spindle transmission structure greatly simplifies the structure of the spindle box and the spindle, and effectively improves the rigidity of the spindle components.
This reduces the load-bearing capacity of the CNC machine column, thereby reducing the heavy load of the spindle head, reducing the deformation of the machine column, simplifying the transmission chain, and greatly improving the response time of the spindle.
Technical Essentials:
The electric spindle has the characteristics of high sensitivity, low vibration, no backlash, etc. that other transmission spindle forms do not have. However, it puts forward stringent requirements on the sealing of the spindle. According to statistics, 80% of the spindle damage is caused by the spindle seal.
The lubrication of the machine tool shaft is generally lubricated with lubricating oil, and the shaft bearing is generally lubricated with grease. In actual work, mixed impurities such as shaft lubricating oil, cutting fluid, dust, etc. will flow into the shaft bearing, causing the grease in the shaft bearing to lose or deteriorate, and damage the bearing when the bearing is running.
An outer ring spacer is provided between the inner ring flange cover and the shaft, the inner ring flange cover is provided with an inner groove, and the outer ring spacer is provided with an annular boss one, and the annular boss one is embedded in the inner groove to form a labyrinth seal, which effectively improves the sealing effect and sealing ability.
The two ends of the bearing seat are labyrinth seal structures, and the oil-blocking spacer has the function of oil throwing, which effectively improves the sealing effect and sealing ability. Even if a small amount of lubricating oil and cutting oil enter the labyrinth, it can flow out through the oil drain hole and will not enter the bearing. A sealing ring is set between the oil-blocking spacer and the rotating shaft, which further improves the sealing effect, effectively isolates the invasion of foreign impurities, protects the rotating shaft bearing well, and improves the service life of the spindle bearing.
What is an excellent electric spindle?
It has high cutting rigidity at low speed, can suppress high-speed vibration at high speed, and can maintain cutting accuracy at different speeds.
High acceleration and deceleration capability, reaching the spindle working speed in the shortest time, and the response time is close to 0.
The spindle has high sensitivity, no noise, low vibration, and no backlash.
It can be quickly maintained to reduce the loss caused by downtime.