A few kinds of circumstances in locating workpiece locates completely locate not complete fixed position owes fixed position to cross fixed position completely

05 ㎜ depend on the dimension of milling cutter; To assure the parallelism of bottom land face and A face and dimension ㎜ two machine a requirement, must restrict, , 3 freedom are spent; To assure the parallelism of groovy flank and B face and dimension 30±0.

1 ㎜ machines a requirement twice, must two limitation, freedom are spent; Because the chamfer of place mill is not a chamfer, on length direction, the dimension of right end panel of workpiece of the distance that carry a department is 50 ㎜, must restrict freedom to spend so. For this, answer workpiece to use the means of complete fixed position, choose A face, B face and right end panel to make fixed position fiducial. (2) locates the treatment according to workpiece asks not completely, the complete freedom that does not need to restrict workpiece is spent, such fixed position, call not complete fixed position. If pursue,3-7 place is shown. Graph (A) machines via to be on lathe, the basis machines a requirement, do not need limitation and two freedom to spend, reason holds limitative the rest with clip of 3 ungual chuck 4 freedom are spent, can come true to located at 4 o'clock. Graph (B) is flat workpiece surface grinding, workpiece has ply and parallelism demand only, reason needs to restrict only, , 3 freedom are spent, electromagnetism workbench is used to be able to come true to located at 3 o'clock on grinder. According to the treatment requirement of workpiece, the freedom that should limit is spent without completely confined fixed position, call owe fixed position. Owe fixed position to cannot assure to machine a requirement, it is so absolutely unallowed. If graph 3-8 place is shown, workpiece is in bearing 1 with two cylinder is sold 2 on fixed position, press this orientation way, freedom is spent was not restricted, belong to owe fixed position. Workpiece is decided in the positional inaccuracy on X direction, if the double dot in the graph underlines the position and dotted line position, the seat that gets a hole accordingly is doubtful also calm, cannot assure the precision of dimension A. In X direction only the setting stops after promoting, workpiece acquires firm position in X direction ability. (Two when 4) crosses fixed position clamping apparatus to go up or the fixed position component of two above, those who duplicate limitative work is same or a few phenomena that spend freely, had called fixed position. If pursue,3-9 place shows two kinds of case that locate too. Graph (A) combines position condition for aperture and end panel, because main aspects limitation, , 3 freedom are spent, long annul limitation, and, 4 freedom are spent, visible, limitation be repetitioned by component of two fixed position, had appeared to locate. Graph (B) sells case of associated fixed position for plane and two short cylinder, planar limitation, , 3 freedom are spent, two short cylinder are sold restrict respectively, and, in all 4 freedom are spent, spend limitation be repetitioned freely, had appeared to locate. Locate the likelihood causes following consequence too. CNC Milling