Parallel rulers are used in machine tool inspection to check the unevenness and straightness of two working surfaces. They are used in conjunction with block gauges, micrometers, level gauges, and other instruments to inspect the parallelism and non connection of two guide rails at different heights. They can also be used in conjunction with a right angle ruler to measure the perpendicularity of two components that cannot be inspected with a right angle ruler alone. They are also suitable for equipment installation and inspection.

Inspection method for parallel rulers

The working surface of the straightedge shall not have defects such as sand holes, air holes, cracks, slag inclusions, shrinkage, scratches, bumps, rust spots, etc. that seriously affect the appearance and performance.

Firstly, support the I and II shaped straightedge with equal height blocks at the standard bearing marks 2L/9 from both ends of the straightedge. Select the appropriate bridge deck according to the length of the working surface of the straightedge (usually 8-10 steps, span)

Distance between 50~500mm); Then place the bridge deck at one end of the ruler and fix the reflector or level on the bridge deck; The bridge board is gradually moved from one end of the flat ruler to the other end according to the span. For each span moved, the position reading is taken from an autocollimator with a division value of 1 "(or 0.005mm/m) or an electronic level with a division value of 0.001mm/m (a composite level with a division value of 0.01mm/m can be used for a first level flat ruler with a working face length greater than 500mm, and a frame level with a division value of 0.02mm/m can be used for a second level flat ruler). The difference between the large and small values is the straightness error of the flat ruler working face. For any 200mm straightness error of the working face, a 50mm or 100mm bridge board can be selected, and the width of the working face can be inspected and determined within any 200mm according to the above method. Any ruler larger than 60mm should be inspected according to the flatness requirements, and its flatness tolerance value should not exceed the specified straightness tolerance value. Only with accurate straightness of the straightedge working surface can the errors caused by workpiece detection be reduced.