Its advantage is to directly reflect the linear displacement of the table or tool rest, the disadvantage is that the measuring device should be equal to the length of the stroke, which is a great limitation for large CNC machine tools. In connection measurement, the linear displacement of the table is indirectly measured by the rotary movement associated with the linear movement of the table using a turntable measuring device. Its measurement accuracy depends on the precision of both measuring element and transmission chain of machine tool.
Indirect measurement using reliable, convenient and no length limit, the downside is joined the line measurement signal is transformed into the rotary motion transmission chain error of linear measuring precision detection device and linear inductosyn inductosyn is a kind of electromagnetic high precision displacement detecting element in different ways according to its structure can be divided into two kinds of linear and rotary. The linear induction synchronizer consists of a fixed ruler and a sliding ruler which move in parallel. There is about a uniform gap between the fixed ruler and the sliding ruler. The fixed ruler is fixed on the stationary part of the machine tool, and the surface is made of continuous windings. The slide ruler of corrugated paper production line can move with the moving parts of machine tool. In order to distinguish the direction of movement, its winding is divided into sine winding and cosine winding to output two signals of phase difference. When working, give slide rule winding pass with ac voltage, due to electromagnetic induction in the fixed rule winding induced electromotive force, its amplitude and phase change with the change of the relative position between slide rule and fixed rule, induction synchronizer is to use the change of the induced electromotive force to measure. The measuring precision of the induction synchronizer mainly depends on the dimensional precision of the sizing winding along the length direction. The closed-loop servo system composed of the induction synchronizer can make the NC machine tool obtain higher machining precision, but to get the ideal measuring effect, it requires high requirements for mechanical parts and installation and debugging.
In order to prevent oil pollution and iron filings from encroachment and scratches on the windings of fixed ruler and sliding ruler, resulting in short circuit and damage of induction synchronizer caused by corrugated production line, the protective cover of ruler is required to be higher. Induction synchronizer is characterized by high precision, operability, strong resistance to disturbance, simple maintenance, long life, long distance position measurement, low cost, easy to batch production. Grating measuring device grating measuring device is a kind of non-contact measurement, which converts mechanical displacement or analog quantity into digital pulse and feeds back to the device to realize closed-loop position control. Due to the use of optical path to reduce mechanical error, with high precision, fast response and other characteristics, so it is a commonly used detection components of CNC machine tools and digital display system, the picture is light ðª² measurement system, by the lighting system ruler grating indicating grating and photoelectric receiving components The scale grating, also called long light shed, is fixed on the moving parts of the machine tool. The indicating grating and photoelectric receiving element are installed on the fixed parts of the machine tool. The indicating light shed is also called the short light book. The two gratings are parallel to each other and keep a certain distance. , a long strip of optical glass is evenly carved with many stripes perpendicular to the direction of motion, and the distance between the stripes is called the grid distance. The grid spacing can be determined according to the desired precision, usually one line per millimeter. If the indicating grating is rotated at a very small Angle in its own plane, the stripe lines of the two light shed will meet.