MITS Eleven Auto FPZ-31AT, Command Manual, Page: 49 / 108

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Surface Button
This button is used for absolute milling method. For the normal milling, incremental milling
method is used.
Incremental milling method is a method that the pressure foot holds the substrate down
and milling is done by the tool bit sticking out from the pressure foot. Absolute milling
method is a method that does not hold the substrate down. Instead, the position of the
Z-axis (the depth) is controlled and fixed numerically by the software.
Click on the “Surface” button on manual operation window. The spindle motor will activate
and the surface window will open.
Normally, when you click on the “DOWN” button on the manual operation window, the
spindle head will go all the way down. In the surface window, by changing the “Z move”
values, you can control the movement of the spindle head by clicking the “Z+” “Z-” button.
The distance from the tip of the tool bit to the surface is written in the “To Surface” field. By
clicking on the “Z-” button, the spindle head will lower down and the value in the “To
Surface” will also decrease.
When the tip of the tool bit is about to touch the substrate, theoretically the value in the “To
Surface” should be 0. However, in actuality there is an error. This error is accumulated
from the many criteria; thickness of the substrate, underlay, length of the tools, flatness of
the table, etc.
You can revise this error by adding the value to the “Thickness” or “Underlay” in manual
operation window. The more accurate you have the distance to the surface from the tool
bit the more accurate milling depth result will follow.
For the incremental milling method, since the pressure foot is holding the substrate down,
the milling depth is determined by how much tool bit is sticking out from the pressure foot.
In absolute milling method, it is possible to mill semi-three-dimensional. In that case, the
pressure foot must be displaced.
WARNING: This machine is capable of performing semi-three-dimensional milling.
However, since there is a spring installed inside the Z-axis movement controller, the
desired milling depth will not be resulted if there is a force or pressure exceeding the force
of the spring.