CNC Knowledge: Why does the tour produce vibrations? Present several elimination measures!

One of the common defects in the turn is vibration. When the turn is vibrated, the normal cutting process of the craft system is disturbed and damaged, which not only seriously deteriorates the quality of the treatment surface, but also shorten the life of the machine and the tools. Therefore, it is necessary for us to take certain measures to reduce or eliminate the vibration of machine tools.
1. The main characteristics of low frequency vibrations

After eliminating the vibration of the rotation component of the machine tool and the transmission system, the main type of turn vibration is the self-excitement that does not change with the driver’s speed. Today, we mainly introduce the causes of low -frequency vibrations caused by the deformation of the part system and the deformation of the blade system during the processing process and its elimination measures. The main characteristic of low frequency vibrations is:

① Low vibration flask (50-300Hz), the noise emitted during vibrations is low;

② The traces left on the cutting surface of the room are deep and wide;

③ The vibration is relatively severe, often loosening machine tools (such as the tail seat, blade, etc.) and the hard alloy blade is broken.

Second, the cause of low -frequency vibrations

When the low -frequency vibration in the car is cut, the part system and the blade frame system are generally vibrated (but in most cases, the part system is large and plays a dominant position). During the vibration process, when the part and the tool are separated, the FEU force F is the same as the direction of movement of the part, and the work is positive, as shown in Figure 1 (A). When the part approaches the tool, the FE force F approaching the merit is negative, as shown in Figure 1 (B).

During the rotation process:

① The food of the dandruff and the surface of the front knife of the tool,

② The degree of hardening of the metal encountered during the cut and output of the part is different.

③ During the vibration process, the real geometric angle of the knife changes periodic changes,

④ During the vibration, the tools of the tool for the relative movement of the part are oval, which causes periodic changes in the -off cutting section.

⑤ The traces left by the vibration of the part in the previous turn caused the periodic modifications of the cutting section of the cutting section. The five situations can cause periodic changes in the cutting force and leave F that F separated> FR approached. In this way, in each vibration cycle, the positive power of the cutting force in the room (or with a knife) is always higher than its negative work for the part (or the tool), so that the part (or The knife) can be reconstituted by energy supplementation and generates the supplement of energy generated.

3. Elimination measures for low frequency vibrations

(1) In low -frequency vibrations, the cutting force is mainly caused by the vibration of the Y direction, which means that F leaves the approach and the vibration.

Mainly take the following 4 measurements.

① The larger the corner of the knife, the larger the Fy force, the smaller the force FY and the less it is likely to produce vibrations. Therefore, correctly increase the main corner of the entire knife to eliminate or reduce vibrations.

② Increase the front corner of the tool properly, which can reduce the Fy force, weakening vibration.

③ The corner of the knife is too large or the blade is too clear. When the tool is properly passed, the knife surface has the effect of preventing the tool from “entering” the part, which can reduce or eliminate vibrations.

④ The position of the tip of the knife is too low (under the center of the room) or the position of the tip of the tip of the knife when the hole is too high on the tower, which will increase the real front of the real front of The tip of the knife to increase and the rear angle will be subject to vibrations.

⑤ If the blade system has a negative rigidity, it is easy to “enter” the part to generate vibrations.

Therefore, the negative rigidity of the blade system can be avoided as much as possible.

(2) When a wide and thin film during the cutting process, the vibration of the steering causes changes in the cutting force. and the cutting force. Therefore, it is very easy to vibrate in this case. For example: when the sword is cut, the larger the depth, the larger the quantity of food and the lower the main corner, the larger the cutting section, the more vibrations it produces. Therefore, when choosing a turn speed, you must avoid the average speed zone where the cutting force decreases with speed (when carbon steel is cut, the speed range is 30 to 50 m / min), and at the same time, reduce the power of the cut of the car, increase the amount of flow and the amount of flow and the quantity of power and the amount of flow and the amount of flow and the amount of flow and the amount of flow and the amount of flow and the quantity of food and diet.

(3) The insufficient rigidity of the part system and the blade frame system is the main cause of low -frequency vibration.

① Use three claws or four claws to tighten the part as much as possible and minimize the same axis error in the room’s circulation center and the main tree rotation center.

② When the treatment is thin and long, and it is easy to deform and fold the part, it uses the elastic and auxiliary support to add the cooling liquid to cool to reduce thermal expansion and the room deformation.

③ When installing the part, do not stretch the room that is too long. For parts with insufficient rigidity, the auxiliary branches such as reasonable central racks, the Hengeges and the summits are used to increase the rigidity of the part.

④ When you use the top, the upper and upper cone holes must be matched well to avoid too much on the upper power to be folded or the upper power is too small to support the part to swing and pay attention to the extension of The tail The siege sleeve cannot be too long.

⑤ The space between the main tree of the tool-tool directly affects the rotation accuracy and the rigidity of the main axis. And the prior force must be applied to increase the rigidity of the part system to eliminate vibrations.

⑥ Regularly check the contact situation of the Aronde guide rail between the trailer and the large trailer, the small blade frame and the medium trailer, and adjust the oblique inlays to keep it by keeping the right space to avoid to crawl when the blade is moved, causing the blade system to be vibrated.

刀 When the knife grid is turned towards the required position each time, the blade shelf must be pressed and fixed to prevent the square knife rack from loosening and reducing the rigidity of the blade system to produce vibrations.