Preliminary remark: expansion
Control of measuring machines

Both the CMM and the product being measured undergo expansion and deformation as their temperature changes.

If the shape of the product is simple, it expands as its temperature rises, with a variable inertia depending on its exchange surface.

CMMs, which are often assembled from a variety of materials, expand, on the one hand with an inertia that differs from that of the product, and on the other hand by deforming, since thermal variations are rarely homogeneous throughout the machine volume.

When the thermal regulation of the room where the machine is installed is not compatible with the expected performance, this induces phenomena, the most serious of which seems to be the rapid and significant degradation of the CMM's geometric qualities, which can lead to the elimination of correct parts or the acceptance of...