G dictates (preparative function) the G that instruction of preparative function G uses address word O and two digit value to express to share Goo -G99 interconnected system dictates instruction of function each G presses a function to be divided into a certain number of groups, next watches are China in 1 model numerical control system, by the function cent becomes a certain number of groups. Among them a few groups instruction calls statement of G of type of the form that be not a chess, its a demarcate is effective in the block that is appointed. The G instruction of the others group belongs to instruction of mode type G to have successional should be the same as group other G only in follow-up program before the instruction did not appear differ effectively all the time the G instruction of the group is in same can dictate in block many with bright G instruction is in middle finger of a block. The coordinate of G instruction ＊ related watch coordinate department fastens set G92 to dictate G92X ___Z ___ ; should dictate is a regulation the distance X that nods workpiece origin to the knife, Z is pair of knives to nod the coordinate in workpiece coordinate department namely. After β of Z of α of executive G92 X dictates, systematic interior is opposite namely (α , β ) have memory, the well builds to make cutting tool nods coordinate value to be currently (α , β ) coordinate is, the system controls cutting tool to press a program to undertake machining in this coordinate department. Carrying out this instruction to build a coordinate only is, cutting tool does not produce motion. When implementing this directive, if cutting tool is bit more current,be fitly on a α of a coordinate department and β coordinate value, already current drop is in cutting tool to be nodded to the knife locally, built this coordinate department is workpiece coordinate department namely, add origin and program origin coincide. If cutting tool nods the α that does not fasten in workpiece coordinate and β coordinate value currently,go up to machine origin and program origin abhorrent, the product that treatment gives has an error or discard as useless, it is dangerous to appear even. If want to be machined correctly, treatment origin and program origin must consider to be same point when consistent reason process designing. As to consistent at 2 o'clock by finish to the knife when the operation. For example, place of graph 1 -3 shows the set that coordinate fastens, when with workpiece left end panel is workpiece origin, answer to build workpiece coordinate to fasten by be issued to lower levels. G92 Xvalue="18" UnitName="oz">18.
When Z254 should be workpiece origin with workpiece right end panel, answer to build workpiece coordinate to fasten G92X 18 by be issued to lower levels.
2114 apparent, differ when α , β , or when changing cutting tool position, already current drop is not in cutting tool to be nodded to the knife locally, machine origin and program origin abhorrent. Uncontrollable cutting tool is in the system workpiece coordinate is medium, by the program of the work out treatment gives correct work. Because this is before β of α of executive block G92 X, Z, must be opposite first knife. What X, Z is worth is affirmatory, nod the coordinate value below workpiece coordinate department to the knife certainly namely. The general principle that its choose is: 1, convenient maths is calculated and simplify process designing; Search 2, easily to be opposite knife: 3, facilitating treatment is checked; The 4, machining error that cause is small: 5, do not collide with machine tool, workpiece happening; 6, convenient disassemble workpiece: 7, idle stroke does not want too long: CNC Milling