The heavy-duty deep-hole drilling and boring machine is often questioned when deep-hole prototype machining of large reverse parts, and it needs to be analyzed from the two aspects of the workpiece system and the drilling system.
Anatomy from a workpiece system
According to the characteristics of deep hole processing, the method of mounting reverse workpieces on the workpiece bed can only be one card, one drag or two drag methods. The one-card, one-drag method is that the disk clamps one end of the workpiece to transmit torque and carry the component of the workpiece, and a base frame supports the other end of the workpiece. The two-drag method is that the two base frames are separated from the left and right ends of the support workpiece, and the faceplate is only used to transmit torque and does not carry the component of the workpiece.
For workpieces with large components and long lengths, there are objective deflections due to their own components. No matter which mounting method is adopted, deflection cannot be avoided, so in practice, although the operator is very high, it is not possible to adjust the reverse axis of the workpiece into a straight line, so the workpiece will often occur during the rotation process. The faceplate claws sound, and the base frame rollers are damaged.
Analyze the main reason for the sound of the disc jaws: the appearance of the jaws and the workpiece being held is a rigid touch, and the workpiece is deformed due to its own weight, causing the jaws to be uneven in the axial direction. In the stopped state, the upper jaw and the lowest jaw are opposite in magnitude in the axial direction. When the faceplate rotates the workpiece through the jaws, the jaws are subjected to alternating loads. The heavier the workpiece, the longer the length, the greater the deflection of the workpiece, and the greater the alternating load on the jaws. The appearance of a crackling claw sounding.
In practice, the method of padding copper between the jaw and the workpiece is often used. When the jaw is subjected to a large alternating load, the copper skin is compressed and deformed, so that the uneven force on the outer surface of the jaw in the axial direction can be released, which has an excellent effect. This method has been widely used on heavy horizontal lathes.
Analyze the main reason for the damage of the base frame roller: In practice, the operator tries to make the reverse axis of the base frame roller parallel to the reverse axis of the workpiece. It is expected that the touch line between the base frame roller and the workpiece is parallel to the reverse axis of the workpiece. . However, due to the deflection of the workpiece due to its own weight, the base frame rollers are subject to uneven forces and eccentric loads in the axial direction. The heavier the workpiece and the longer the length, the greater the deflection and deformation of the workpiece, and the more severe the eccentric load of the base frame roller in the axial direction. When part of the load is greater than the allowable stress of the base frame roller data, the base frame roller is compressed and deformed, and the flange flange screws at the end face are broken in severe conditions, and the internal bearing is damaged and cannot be used continuously.
Special curved roller bearing developed for this purpose, the bearing directly supports the workpiece as a roller. Because the bearing material is bearing steel and is heat-treated, it has a high hardness as a whole, and it is not easy to be deformed by compression. The surface of the bearing is a curved surface with a large diameter in the axial direction, so that the touch line is as large as possible and the partial load is relieved , Get an outstanding role in practical use. When there is a high demand for the machining accuracy of the workpiece, two base frames should be used to support the component of the workpiece, and touching the workpiece as the support tile construction method.
Analysis from the drilling system
Common questions such as the oil receiver can not seal the oil, poor chip removal and so on.
Analyze the main reason that the oil receiver cannot seal the oil: When the internal chip discharge deep hole machining method is used, the end face of the rotating sleeve of the oil receiver organization is required to press against the end face of the workpiece and rotate with the workpiece. When the end face seal is in doubt, it will Oil leakage and even high-pressure oil suddenly sprayed out from the end face of the rotating sleeve of the oil receiver, and drilling could not be performed normally. There are three reasons for this appearance:
(1) The tightening force of the oil receiver is small. When the tightening force is less than the thrust of the high-pressure oil, the high-pressure oil will push the receiver away, and the high-pressure oil will spray out in a short time;
(2) The end face of the workpiece is skewed. The seal between the end face of the workpiece and the end face of the rotating sleeve of the oil receiver is usually selected by using harder rubber materials for sealing. The deflection of the end face of the workpiece will cause uneven force in the axial direction of the sealing part and seal the part with small axial force Poor, easy to show the appearance of oil leakage, in severe cases, oil flows out of the end surface of the workpiece like water flow;
(3) Blocking debris. Due to improper adjustment of cutting parameters, chip breaking effect is poor during drilling, and long chips can not be discharged in time from the inner hole of the drill pipe. The system pressure becomes higher and higher. Push the oil receiver away, and the high-pressure oil splashes out in time.
The treatment methods are:
(1) The tightening force of the oil receiver is small. The hydraulic system of the machine tool should be adjusted to increase the jacking force. For machines without a hydraulic system, a torque wrench should be used to increase the jacking force according to the calculated value.
(2) The end face of the workpiece is skewed. Before cnc machining deep holes for internal chip removal, the end face of the workpiece should be turned flat;
(3) Blocking debris. Adjust the cutting parameters to break the chip into a shape that is easy to remove chips. If the workpiece material is special, the blade material needs to be replaced to reach the chip breaking intention, and sometimes the overall tool body structure is replaced for normal cutting.
Analysis of the main reason for poor chip removal: When the internal chip removal deep hole cnc manufacturing method is used, chips need to pass through the inner hole of the drill pipe and the base hole of the main shaft of the drill pipe before they are discharged to the iron chip collector. The poor chip removal mainly occurs at the intersection of the inner hole of the drill pipe, the base hole of the main shaft of the drill box, the base hole of the main shaft of the drill box, and the iron chip collector. Usually it is because of continuous chipping and poor chip removal when showing long chips. The solution includes:
(1) Select reasonable cutting parameters and reasonable raw materials of the insert, and repeat the adjustment to reach the chip breaking intention;
(2) Because the structure of the inner hole of the drill pipe is limited, the machine tool should be improved in structure to increase the drill box box spindle base hole as much as possible, and increase the curvature at the junction of the drill box box spindle base hole and the iron chip collector. , To reach the intention of facilitating chip removal.
