The guide rail is the benchmark for determining the relative positional relationship of various machine tool components on the machine tool, and also the benchmark for machine tool movement. The accuracy requirements of lathe guide rails mainly include the following three aspects: straightness in the horizontal plane; straightness in the vertical plane; parallelism of the front and rear guide rails. In addition to the manufacturing error of the guide rail itself, the uneven wear and installation quality of the guide rail are also important factors that cause the guide rail error.
After years of research by Chuangweida, we have summarized the THK guide rail calculation error. This situation is mainly due to two reasons. I hope everyone can pay attention to the calculation.
When studying the linear motion of the guiding link of the mechanism, there may be two situations
1. The line of action of the working point of the guiding link intersects at point P;
2. The lines of action of the working points are parallel to each other.
Since each situation has its own characteristics, it should be studied separately.
In the first case, the lines of action intersect. When the line of action of the working point through the guiding link intersects at point P, it is necessary to study the characteristics of linear guide errors in connection with the following facts, namely: the instantaneous rotation center O can move to infinity, and the baseline PP passes through the point P and moves with the theory The trajectory is perpendicular. Taking this feature into account, the calculation can be carried out using equations (II.34) and (II.35). It must be understood as the trajectory error of the dead point or the trajectory error of any point on the PP normal.
Installation summary of linear guide
A. Straighten and fix the reference guide rail;
B. Straighten the parallelism of the second guide rail and connect it to the lower installation table in advance (not fastened);
C. The slide block of the reference guide rail and the second guide rail is pre-connected with the upper working table (not fastened), the slide block and the upper working table repeat the full reciprocating movement on the reference guide rail and the second guide rail to tighten the reference guide rail The sliding block and the upper working table are fastened, the sliding block of the second guide rail and the upper working table are fastened, and the second guide rail and the lower mounting table are finally fastened.
note:
1. The tightening force should be balanced.
2. In the process of straightening the parallelism of the second guide rail, when the level gauge measures the height difference between the starting point and the end point of the two guide rails, the height difference must be reduced due to the fastening between the connecting parts. The effect of this is due to the fact that the upper working table is deformed toward the neutral reference surface due to the fastening between the connecting parts. Therefore, the height difference should be enlarged by 1.1-1.3, and re-check after all installation.
3. The method of grinding or scraping to straighten the guide rail can ensure high precision and high rigidity.