The accuracy inspection of guide rail is the key link to ensure the stability and machining accuracy of mechanical equipment。The accuracy check of guide rail mainly includes straightness、parallelism、Surface roughness and other aspects。The following are some commonly used guide rail accuracy check methods：

1. Straightness check

Straightness is one of the core indexes of guideway accuracy，The main inspection methods are as follows：

• Lapping point method：

• principle：Use a standard square and the guide rail to be tested，The straightness of guide rail can be judged by observing the number and distribution of contact points。

• procedure：Apply a thin layer of red powder evenly on the surface of the guide rail to be inspected，Make the inspection surface of the flat ruler fit with the surface of the guide rail to be inspected，Do short distance reciprocating movement of the lapping point under appropriate pressure。Then take off the ruler，Cover the detected guide rail with a square frame，Observe the number and distribution of contact points。

• Matters needing attention：The precision of the flat ruler should meet the accuracy requirements of the guide rail to be inspected，And the length should be greater than the length of the guide rail to be inspected（When the demands are not high，Shorter than the guide rail to be detected1/4）。This method is commonly used to measure lengths less than1500mmShort guide。

• Wire method：

• principle：The wire after tension is used as an ideal straight line，The straightness error of the guide rail is evaluated by measuring the deviation of the steel wire from the guide rail。

• procedure：Fix a small pulley at each end of the bed guide rail，Use a diameter of approximately0.1mms wire，One end is fixed to the pulley，The other end hangs a heavy weight。Adjusting wire ends，Make the microscope at both ends of the guide，The wire overlaps with the cut of the lens。Then move the pad iron，Look at the microscope every certain distance，Check whether the wire coincides with the cut，And record the reading。

• Matters needing attention：The weight of the weight of the weight should be the breaking force of the wire50%～80%，To ensure that the wire is tight and stable。

• Method of level examination：

• principle：Use a level to measure the inclination Angle of each point of the guide rail relative to the horizontal plane，The straightness error of the guide rail is obtained by calculation。

• procedure：Fix the level to the pad iron，Move the pad iron in turn，Measure the tilt Angle of each point of the guide rail，And record the reading。Then draw the line straightness curve according to the reading，Calculate straightness error。

• Matters needing attention：The accuracy of the level and the length of the pad iron should be selected according to the length and accuracy requirements of the guide rail。

2. Parallelism check

Parallelism is the degree of parallelism between the guide rail plane and the datum plane。The inspection method usually uses measuring instruments（Such as laser interferometer、Parallelism measuring instrument, etc）Direct measurement of the guide rail，The parallelism error is evaluated by comparing the deviation between the guide surface and the datum surface。

3. Surface roughness inspection

Surface roughness is one of the important indexes of surface quality of guide rail。The inspection method usually uses a roughness measuring instrument to measure the surface of the guide rail directly，The concrete value of surface roughness is obtained，And compared with the design requirements。

4. Other inspection items

Except straightness、Parallelism and surface roughness outside，The accuracy check of the guide may also include dimensional accuracy、hardness、Abrasion resistance、Fatigue resistance、Corrosion resistance and installation accuracy。These inspection items usually require the use of appropriate measuring instruments and test equipment to carry out。

Sum up

The accuracy inspection of guideway is a comprehensive process，It depends on the specific type of guide rail、Use and accuracy requirements to select the right inspection methods and measuring instruments。During the inspection，It should be operated in strict accordance with relevant standards and specifications，Ensure the accuracy and reliability of the inspection results。meanwhile，The problems found in the inspection should be dealt with and repaired in time，To ensure that the accuracy and performance of the guide rail meet the design requirements。