Apparatus for the lightening of panels or thin plates by removal of material

Method for mapping at least a portion of the surface of thin, flexible and shaped workpieces, such as panels, plates or sheet metals, the method comprising the steps of

• a) arranging an apparatus comprising:
• a mobile portal machining unit provided with at least one tool,
• a fixed worktable or movable with respect to the machining unit to receive and support a pre-shaped workpiece to be machined, and counterthrust means configured to rest against a part of a surface of the workpiece opposed to a surface on which said tool works, the worktable comprises:
• a supporting mechanism, configured to constitute a bed or a variable configuration plane for a transitory support of the workpiece to be machined, and
• a gripping mechanism configured to support the workpiece during its machining independently from said supporting mechanism, and the counterthrust member comprises a board carrying a plurality of supporting elements facing towards the workpiece to be machined,
• wherein said board is movable according to several axes and said supporting elements can be operated individually or in groups between a proximal position with respect to the board and a distal position with respect to the board to define a supporting plane conforming to the shape of the surface of the workpiece against which the counterthrust member must rest and arranging the workpiece to be machined on the worktable of said apparatus;
• and
• b) positioning said board at a corresponding portion of the workpiece to be mapped;
• c) moving one or more of said supporting elements with respect to the board and displacing said supporting elements in abutment against the surface of the workpiece;
• d) detecting travel run by each of said supporting elements to displace in abutment against the surface of the workpiece;
• e) calculating, based on the detection of the step d), the coordinates of each surface point of the workpiece against which a supporting element was displaced in abutment;
• and
• f) repeating steps b)-e) for mapping one or more surface portions of the workpiece, or whole surface of the workpiece.