Installation guide for grating scales
Generally, the main ruler is installed on the worktable (slide board) of the machine tool, and moves with the machine tool, and the reading head is fixed on the bed, so that the reading head is installed below the main ruler as much as possible. The selection of the installation method must pay attention to the splashing direction of chips, cutting fluid and oil. If it must be installed with the reading head facing up due to the limitation of the installation position, an auxiliary sealing device must be added. In addition, in general, the reading head should be installed on the stationary part relative to the machine tool as much as possible. At this time, the output wire is not moved and easy to be fixed, and the ruler body should be installed on the part that moves relative to the machine tool (such as a sliding plate).
When installing the grating ruler displacement sensor, the sensor cannot be directly installed on the rough and uneven machine body, let alone the machine body with primer coating. The grating main ruler and the reading head are respectively installed on the two parts of the machine tool that move relative to each other. Use a dial indicator to check the parallelism between the main ruler mounting surface of the machine tool table and the direction of the guide rail movement. The dial indicator is fixed on the bed and the worktable is moved, and the parallelism is required to be within 0.1mm/1000mm. If this requirement cannot be met, a grating scale base needs to be designed and processed.
The base requirements are as follows: (1) A base with the same length as the grating ruler should be added (preferably, the base should be about 50mm longer than the grating ruler). (2) The base is processed through milling and grinding processes to ensure that its plane parallelism is within 0.1mm/1000mm. In addition, it is necessary to process a reading head base with the same height as the ruler base. The total error between the base of the reading head and the base of the ruler should not exceed ±0.2mm. During installation, adjust the position of the reading head so that the parallelism between the reading head and the scale body is about 0.1mm, and the distance between the reading head and the scale body is about 1~1.5mm.
Main ruler installation
Use M4 screws on the grating main scale on the worktable installation surface of the machine tool, but do not tighten it, fix the dial indicator on the bed, and move the worktable (the main scale and the worktable move at the same time). Use a dial indicator to measure the parallelism between the plane of the main scale and the direction of movement of the machine guide rail, and adjust the position of the M4 screw of the main scale to make the parallelism of the main scale within 0.1mm/1000mm, and then tighten the M2 screw completely.
When installing the grating main ruler, the following three points should be paid attention to:
(1) When installing the main ruler, if installing gratings over 1.5M, it is not possible to install only the two ends as in the bridge type, and the entire main ruler needs to be supported. (2) After installing with a base, it is best to use a clip to hold the midpoint (or points) of the ruler. (3) When the clip cannot be installed, it is best to stick the grating ruler body with glass glue to make the base ruler and the main ruler well fixed.
When installing the reading head, if you find that the installation conditions are very limited, you can consider using accessories, such as angle aluminum and straight plates. First, ensure that the base surface of the reading head meets the installation requirements, and then install the reading head. The installation method is similar to the main ruler. . Finally, adjust the reading head to ensure that the parallelism between the reading head and the grating main scale is within 0.1mm, and the gap between the reading head and the main scale is controlled within 1~1.5mm. After installation, you can use your thumb to touch whether the surface of the reading head and the scale body is smooth and flat.
After all the grating line displacement sensors are installed, a limit device must be installed on the machine guide rail to prevent the reading head from colliding with both ends of the main ruler when the machine tool moves, thereby damaging the grating ruler. In addition, when purchasing a grating linear displacement sensor, the user should try to choose a grating ruler that exceeds the processing size of the machine tool by about 100mm, so as to leave a margin.
After the grating line displacement sensor is installed, you can turn on the digital display, move the worktable, and observe whether the counting of the digital display is normal.
Select a reference position on the machine tool, and move the work point back and forth to the selected position. The DRO should read the same (or return to zero). In addition, a dial indicator (or dial indicator) can also be used to adjust the dial indicator and the digital indicator to zero at the same time (or memorize the initial data), return to the initial position after going back and forth several times, and observe the digital indicator and the dial indicator. Whether the data in the table is consistent.
Through the above work, the installation of the linear displacement sensor of the grating ruler is completed. But for the general machine tool processing environment, there are many iron filings, cutting fluid and oil pollution. Therefore, the sensor should be equipped with a protective cover. The design of the protective cover is determined by leaving a certain space size according to the enlarged cross-section of the sensor. The protective cover is usually sealed with rubber to make it have a certain waterproof and oil-proof ability.