Why is it necessary to ensure that the lower mold and the lower platform are parallel when using a metallographic mounting machine?

When using a metallographic mounting machine, it is very important to ensure that the lower mold is parallel to the lower platform. This can ensure that the sample is placed steadily at the center of the lower mold, and when the handwheel is turned counterclockwise to sink the lower mold and the sample, it can be guaranteed that the observation surface of the sample faces downward. The adjustment of parallelism helps to maintain the accuracy and consistency of sampling, thereby obtaining more reliable metallographic analysis results.