The working principle is explained.
Due to various reasons, the height of the tailstock body will be reduced during long-term use, and the clearance between the tailstock hole and the bushing will increase, and the overall precision will decrease. In the maintenance, the diameter of the tailstock hole is generally enlarged, and the sleeve of the corresponding diameter is selected to meet the requirements of the equal height of the sleeve axis and the spindle axis and its parallelism with the lathe guide rail. How to ensure these requirements in the boring tail hole is a difficult problem in the process of boring the tail hole. For this reason, I designed a differential sliding boring bar and developed its machining process. Now introduced as follows.
The file body 5, the differential cutter head 8, the support frame 11, and the like are composed. The step in which the key groove is formed at the left end of the file body 5 is fitted in the inner hole of the sliding centering sleeve, and is free to slide in the axial direction. The three-jaw chuck 2 is rotated by the slide button 3 together. The stepped surface of the right end of the file body is assembled in the inner hole of the support frame 11 and can be freely rotated, and the support frame on the tool holder is driven by the movement of the large carriage 14 to make the file body move axially. The differential cutter head is fixed by the bolt 9 in the cutter hole at the middle position of the boring tool body, and a screw with unequal pitch controls the cutter head to move along the boring cutter body in the radial direction to meet the requirements of boring different bore diameters.
Working principle The spindle axis of the spindle box 1 is the benchmark for the machining and installation of the differential sliding boring bar, and is also an important basis for determining the height of the centerline of the tailstock hole of the boring lathe. In the boring of the tailstock hole, the support frame should first be clamped on the lathe tool holder 10, and the position of the spindle axis should be corrected to lock the carriage, so that the tool holder must not move longitudinally; use the three-jaw chuck 2 clamp An adjustable boring tool is used to machine the inner hole of the support frame until it is molded to ensure the coaxiality between the hole and the main shaft. Then, the adjustable boring tool on the three-jaw chuck is removed, and the sliding hollow sleeve preform which is opened through the inner key groove is clamped, and after the tool holder is rotated by 180*, the adjustable boring tool is slid by the other position of the tool holder. The inner hole of the centering sleeve is processed, and the tool holder is restored after the hole is formed. Then according to the actual size of the support frame and the inner hole of the sliding centering sleeve, the step of the outer key groove at one end of the file body is matched with the inner hole of the sliding centering sleeve, so that the manufacturing method and the machine tool are processed in the small-sized equipment. When the sphere is out of range, first consider the rigidity of the machine after the transformation and determine the specific processing range.
In the transformation, some new structures and new technologies should be adopted to ensure the processing accuracy according to the specific conditions. For example, we use self-centering fixtures, abrasive belt polishing heads, top horizontal fine-tuning mechanisms, rotary table 4-point clamping, variable frequency speed regulation and detection devices.
Due to the modification of equipment, subject to various conditions, the production cycle can not be forced, it should be determined according to the equipment.
Author: Jin Zhaojun, Qiqihar First Machine Tool Plant, zip code :( edit Lvbo Cheng) (: 2003 * If you would like to comment on this article, please fill in the appropriate position article number reader survey table.
Analysis and Treatment of Limitations of CNC Machine Tool Limits Du Jianghua (Oriental Steam Turbine Works, Deyang 618201, Sichuan) lists some representative examples for analysis and explanation.
Due to the wide variety of machine tool numerical control systems, different equipment shapes and structures, various design methods, and various faults, it is quite difficult to maintain CNC equipment. While mastering the mechanical structure and electrical control principles, it must be reasonably analyzed, flexible, and good at summing up in order to get more results with less effort. Based on the principle, it is easy to difficult to narrow down the fault range and eliminate it. In order to ensure the safe operation of the machine tool, the linear axis of the machine tool is usually equipped with two protection "defense lines": soft limit (parameter setting limit) and hard limit (stroke switch limit). The limit problem is one of the common faults of CNC machine tools, and there is less relevant information. The following is the analysis and explanation of the main causes of the limit alarm.
1 The relevant control circuit is broken or the limit switch is damaged. The cause of the "limit alarm" is relatively high. Because external components are greatly affected by the environment, such as mechanical impact, dust, corrosion, friction and other factors, it is easy to cause damage to the relevant limit switch itself and the control circuit is broken, and at the same time generate "limit alarm" information. Also encountered when the overtravel switch is pressed and cannot be reset. The handling of such faults is relatively straightforward, and the damaged switches and wires can be repaired or replaced. Care should be taken to check and observe when the wire is broken or the contact is poor.
For example, a XK755 CNC milling machine adopts the FANUC0*M numerical control system, and the “X+, X?, Y+, Y-hard limit†alarm suddenly appears during the machining process, but the machine tool is actually in the normal processing range.
According to the above phenomenon, it is estimated that the line is in poor contact or the possibility of disconnection is the greatest.
Measure the 24V voltage of the supply limit circuit on the terminal block of the electrical cabinet, and the pressure value is normal. According to the line direction, one by one, when a hand connector on the right side of the bed is rotated by hand, it is found that the alarm on the screen disappears instantaneously, and the gap of 0.015 mm is loosened, so that it can freely slide axially in the inner hole; One end is matched with the inner hole of the support frame, so that it has a gap of 0.01~0. 015mm, and can be freely rotated in the inner hole. Finally, the tailstock 6 of the machine tool is mounted on the lathe rail 7 between the headstock 1 and the large carriage 14, and the sliding key 3 is loaded into the keyhole of the sliding centering sleeve, and the boring body is sequentially centered from the main shaft and slide. The sleeve, the tailstock and the inner hole of the support frame pass through, and the axial gap between the sleeve and the support body is adjusted by the retaining pad 12 and the nut 13 on the file body, and the sliding centering sleeve is driven by the three-jaw chuck. The upper slide key allows the boring body to freely rotate in the bore of the support frame to produce a main cutting motion. Driven by the large carriage, the support frame on the tool holder freely axially moves the file body in the inner hole of the sliding centering sleeve to form a knife movement, and then the tool hole on the file body is dragged from the right end of the tailstock frame. The differential cutter is mounted, and the lubricating oil is poured into each moving part, and the obstacles can be cut and confirmed by checking and confirming that there is no obstruction in each moving part.
Since the machining of the slide centering sleeve and the inner hole of the support frame is based on the spindle rotation axis, the movement of the cutter is based on the guide rail of the lathe, so the assembled rotation axis of the file body and the spindle rotation axis belong to the same reference, so The cut tailstock hole bore line is at the same height as the spindle axis and parallel to the lathe guide. In addition, the differential feed tool is used to make the shape and size control of the pupil less difficult, and the quality of the pupil is guaranteed.
It has been proved by practice that the structure and processing technology of the differential sliding boring bar can fully meet the relevant precision of the maintenance requirements of the tailstock hole of the machine.
3 Differential sliding boring bar range This differential sliding boring bar is suitable for: Trailing stroke length> Before using this boring bar, all other parts of the machine tool should meet the relevant precision and technical requirements of overhaul regulations.
Author: Wang Zhi, Jiangsu Huaiyin Institute of Technology Department of Mechanical Engineering, zip code :( edit Lvbo Cheng) (: 2003 * If you would like to comment on this article, please fill in the appropriate position article number reader survey table.
Manufacturing technology and machine tools
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