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Instruction and maintenance manual
ENGLISH
8.6 Instructions on how to clamp parts for
traditional machining operations
8.6.1 Flattening - Part clamped directly onto the
magnetic chuck
Magnetic chucks can be typically used to flatten
sheets. After cleaning the sheet and having removed
the burrs, which may increase the air gap and thus
decrease the clamping force (see paragraph 4.3),
position the part to be machined and manually per-
form the shimming operation.
This operation limits the deformations caused by the
system’s magnetic attraction forces and the vibra-
tions produced during machining.
This type of machining offers the advantage of being
able to position the part directly onto the magnetic
chuck, but does not enable to perform machin-
ing operations like contouring, drilling and thread-
ing operations. In addition, the degree of levelness
depends on the ability of the person performing the
operation.
To optimize the clamping action applied to the part
(section 4.3) and positioning, it is possible to use
mechanical stops (paragraph 8.2) in order to offset
the tangential forces that tends to slide the part and
have a reliable reference point.
8.6.2 Flattening - Clamping the part onto the ex-
tensions
To further enhance the performances of the
magnetic chuck and obtain, for example, a good
degree of levelness, it is possible to use mobile polar
extensions that are also supplied as accessories by
TECNOMAGNETE (paragraph 5.1.1).
These extensions can be used to automatically and
consistently shim the sheets to machine with a quick
and accurate procedure. The correct use of these
accessories and of the fixed polar extensions enable
to obtain high levelness and parallelism tolerances
even during the initial milling operation, in addition
to superior final finishes. These accessories also en-
able too reduce the vibrations that may occur when
the clamping forces are not consistently distributed
and consequently also the premature wear of tools.
Place the three fixed polar extensions under the
sheet to machine (paragraph 8.3) and add the mobile
polar extension to strengthen the support surface.
If the thickness of the sheet causes it to bend, use
five fixed polar extensions, placing four along the
sides and one in the center.
STEP ONE – Place the part to machine onto the ex-
tensions and start the magnetization cycle (you will
notice that the mobile polar extensions will adapt to
the sheet profile), then perform the roughing opera-
tion on the upper surface.
STEP TWO – Start the demagnetization cycle and
turn the sheet so that the roughed side is in contact
with the extensions. Rough and contour the second
surface. Before finishing the roughed surface, it is
necessary to perform another magnetization cycle.
The sheet, which has been deformed by the yield
and heating of the material, releases the internal
stress and adapts to the new position. At this point
it is necessary to perform a new magnetization cycle
so that the mobile polar extensions readapt to the
contact surface and then finish the upper surface.
