The vacuum chuck is of such construction that the inside of the
chuck is exhausted by a vacuum pump to reduce the internal
pressure and a workpiece is held by atmospheric pressure.
Therefore, the holding power is determined by a diff erence from
atmospheric pressure and holding area. Due to physical
restrictions, a diff erence in pressure that can be obtained by a
pump is about 80 kPa (600 mmHg) in consideration of the upper
limit of available exhaust effi ciency. Since the same holding power
as about 80 kPa (0.8 kgf/cm2) can be obtained, if the holding area
of a workpiece is 100 cm2, it is held by a holding power of about
800 N (80 kgf). Note, however, if the holding face of workpieces is
rough or distorted, if small, atmospheric pressure leak occurs to
decrease the holding power significantly. For such workpieces,
some leak preventing measures must be taken. Workpieces could
be deformed by heat generated during machining depending on
materials and thickness of workpieces. Pay attention to machining
methods. In particular, thin stainless steel plates deform due to
machining heat largely and are difficult to hold. If you have
questions, please contact us.