The machine tool numerical control transformation of mechanical and electronic design and alignment
One, the necessity of the machine tool numerical control transformation
Nc technology is the core of advanced manufacturing technology, the overall level of it marked the industrial modernization level and the comprehensive national strength of a country, on the strength of the strategic materials status of beyond its economic value. At present our country enterprise machinery manufacturing level there is a great gap compared with developed countries. Because most of China's enterprises rely on imported CNC machine tools and CNC system, the enterprise cannot afford the huge purchase expense, and vulnerable to foreign control, in addition weak CNC machinery and equipment maintenance, import the spare parts of the maintenance cost is high, equipment intact rate is low, most of the imported machine tool numerical control system has collapsed, some even after import haven't use for various aspects reason cannot use and so on. So at present our country enterprise proportion of numerical control machine tool is extremely low, less than 5%, all kinds of the enterprise to use most of the conventional machine tools, it is difficult to meet the demand of enterprise high technology products and production efficiency. To save costs, further exert the efficacy of the old traditional machine tools and potential value, will be a large number of traditional old machine tool for numerical control machine tool is a kind of necessity and trend.
Second, the classification of the machine tool numerical control transformation
The numerical control machine tool transformation can be divided into the following kinds:
1, one is to restore the original function, existing in machine tool fault diagnosis and recovery;
2, secondly, NC, in ordinary machine with digital display device, or add CNC system, transformed into NC machine tools, CNC machine tools;
3, a third is renovated, in order to improve the accuracy, efficiency and degree of automation, the mechanical and electrical parts for renovation, of mechanical parts to assembly processing, restore the original precision; It doesn't meet the production requirements of update to the latest CNC CNC system;
Is 4, its technical updates or technical innovation, to improve the performance or class, or in order to use the new craft, new technology, on the basis of the original large-scale technology updates or technical innovation, greatly improve the level and quality upgrading.
Third, the content of the machine tool numerical control transformation
Below according to the reconstruction of the third way to numerical control lathe as an example, combined with our company in the operation of machine tool transformation to introduce the main content of the reform and the main structure form.
1, the improvement of feed shaft
Ordinary lathe of X and Z axes are driven by the same motor, feeding movement by feeding box drive screw and slip board box, get different workpiece pitch Z axis movement; Feeding movement by feeding box transmission polished rod and the slip board box, get different feed amount X axis movement. Transformation of ordinary lathe numerical control is generally remove feeding box and slip board box, switch to feed servo (or step) transmission chain instead of separately, concrete manifestation is:
Z axis: the vertical motor and reducer (or coupling) - vertical ball screw - big drag board, longitudinal according to nc instructions for different feed and pitch.
X: horizontal motor and reducer (or coupling) - lateral ball screw - cross slide, transverse according to nc instructions for different feed.
After transforming the transmission chain of accuracy in guarantee under the premise of machine tool rigidity, and the selection of ball screw pair and the layout structure, the precision of machine tool guideway conditions has a lot to do.
1), the choice of ball screw pair and layout structure
Most ordinary lathe is T screw sliding screw pair, compared with the ball screw pair friction resistance, low transmission efficiency, cannot be adapted to the high speed movement. Also caused by wear fast, its accuracy stable and low life expectancy and so on, in the transformation of ordinary numerical control machine tool is usually the replacement for the ball screw pair. Ball screw pair has the following features: small friction loss, high transmission efficiency, can reach 0.90 ~ 0.96; If use screw nut and tighten, can completely eliminate the gap and improve the transmission stiffness; Frictional resistance is small, almost nothing to do with speed, the difference of the static friction force, can guarantee the smooth movement, not easy to produce low speed crawl phenomenon; Wear small, long life and good accuracy stable. But should pay attention to, because the ball screw pair cannot self-locking, reversibility, which can convert rotary motion to linear motion, or the linear motion into rotary motion, thus screw vertical and inclined to use, should increase brake or balancing device.