In a CNC operation, a path control method for tool withdrawal and resumption characterized in that said path control method comprising the steps of:
- (a) defining first and second turning points between an interruption point and a destination point:
- (b) defining first and second withdrawal statuses, which will be on when said tool is moving from said interruption point to said first turning point, and from said first turning point to said second turning point, respectively, each of said withdrawal statuses corresponding to a set of predetermined withdrawal path control parameters;
- (c) defining first, second and third resumption statuses, which will be on said tool is moving from said destination point to said second turning point, from said second turning point to said first turning point, and from said first turning point to said interruption point, respectively, each of said resumption statuses corresponding to a set of predetermined resumption path control parameters;
- (d) moving said tool in accordance with an interpolation scheme, said interpolation scheme comprising the following steps:
- (i) deciding whether an interruption signal has be detected, if yes, then deciding if said first withdrawal status is on;
- if said first withdrawal status is on and said interruption signal continues, then continuing said movement of said tool according to said interpolation scheme toward a destination point, if said interruption signal stops then turning on said third resumption status and returning said tool to said interruption point;
- (ii) if said first withdrawal status is off and said second withdrawal status is on, determining if said interruption signal continues, if yes, then continuing said movement of said tool toward said destination point, if said interruption signal stops, then turning said second resumption status on and returning said tool to said first turning point:
- (iii) if said first withdrawal status is off and said second withdrawal status is also off, then determining if said second resumption status is on, if yes, then turning on said second withdrawal status and moving said tool to said second turning point if said interruption signal continues, otherwise returning said tool to said interruption point;
- (v) if said first withdrawal status is off and said second withdrawal status is also off, then if said second resumption status is off, then checking whether said third resumption status is on, if said first resumption status is on then turning on said first withdrawal status and moving said tool to said first turning point if said interruption signal continues, otherwise returning said tool to said interruption point;
- if said first resumption status is off, then returning said tool to said interruption point;
- (e) after moving said tool to said first turning point, checking if said first resumption status is on, if yes then returning said tool to said interruption point, if no then performing the following steps:
- (i) checking if first withdrawal status is on, if yes and said interruption signal continues, then turning said turning said second withdrawal status on and moving said tool to said second turning point, if said interruption signal stops then turning said third resumption status on and returning said tool to said interruption point;
- (ii) if said first withdrawal status is off then checking if said second resumption status is on, if no, then moving said tool to a destination where said tool will be repaired, if yes, then checking if said interruption signal continues, if said interruption continues, then turning said second withdrawal status on and moving said tool to said second turning point, if said interruption signal stops then turning said first resumption status on and returning said tool to said interruption point;
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- (f) said path control method further comprising the step of using a detector attached to a CNC machine to facilitate a correction of factors that may be responsible for causing an interruption of said CNC operation.