PURPOSE: To permit continuous working even if portions are mixed which do not need clamp copying, by performing normal copying when a tracer head reaches newly provided clamp copying neglecting territories while it moves on the clamp level.
CONSTITUTION: When a tracer head is moved in the direction of +X axis by clamp feed and reaches as clamp copying neglecting territory A3, a position monitoring circuit generates signal TDEN, the count value N of a sequence counter 108a becomes 3 and an analog gate circuit 108c provides speed Vx=0, Vz=-Vc. Consequently, the clamp feed of tracer head in the direction of X axis is finished and the clamp feed in the direction of -Z axis is carried out so that the tracer and head descends. When the tracer head contacts a model MDL, displacement >=a is obtained, a comparation circuit generates contact signal CDEN and the count value N of the counter 108a becomes 4 so that the circuit 108c provides speed Vx=Va, Vz=Vb. Thus, the clamp feed in the direction of -Z axis is completed and copying is carried out in the direction of normal surface 1.
MATSUI MITSUO
MATSUURA HITOSHI
SAKURAI HIROSHI
