Ball Screw Slide Module Repositionable
The ball screw slide module can be positioned repeatedly, which can accurately record the accuracy and achieve the best motion effect. Let's look at the accuracy requirements of repeated positioning.
The repeatability of a lead screw slide positioning system refers to the degree to which the actual position of a specific position changes when trying to pass it continuously. There are highly repeatable systems (which may or may not be highly accurate) that show extremely low dispersion of locations in either direction when repeatedly passing the same given location. The difference between moving a point in the same direction (repeatability in one direction), moving a point in the opposite direction (repeatability in both directions), and moving in the opposite direction. Generally speaking, the position change is larger for bidirectional motion than for unidirectional motion. Looking at the unilateral movement repeatability data alone, the effect on the backlash is not obvious.
If the repeatability is high, it is better not to use the lead screw and use the linear motor as the actuator. While this requirement increases the use of linear encoders and the need for both the carriage and the servo controller to operate in closed loop mode, performance is greatly improved due to the encoder's resolution and the inevitable thermal effects.
Although linear feedback sensors can be used to measure the characteristics of a closed-loop positioning system, during repeated movements on an open-loop or rotary encoder carriage, the lead screw is overheated due to friction, resulting in thermal expansion and contraction and positional deviation . As a result, repeatability data for standard positioning slides (rather than the entire servo system) obtained in this way will fully respond to the specific characteristics of the lead screw and nut. Thermal expansion and contraction mainly depend on the operating speed and duty cycle. If the time to repeat the test is too short, it will not be able to respond to the effects of changes in ambient temperature.
While the above approach to eliminating thermal effects on measurement repeatability is overly accurate, we did so to demonstrate the inherent reliability of our anti-backlash nut (used with a lead screw driven slide) Repeat feature. Extensive use of laser interferometry results has shown typical unidirectional values of less than 0.5 microns (with many other products between 0.1 and 0.3 microns) and bidirectional values of less than 1 micron (many products are between 0.2 to 0.2 microns) 0.5 microns). In addition, the anti-backlash nut design is self-compensating and the repeatability value of the unit drops below 5 microns even after prolonged use.
As can be seen from the above, the ball screw slide table mold also has high requirements for repeated positioning accuracy, and the higher the accuracy.