Calibration of measurement probes
A machine tool is provided with a toolsetting probe mounted on a bed or table, and a workpiece-sensing probe which can be mounted in a movable spindle. Both probes are calibrated by using them to make measurements against each other. The arbitrary length of the workpiece-sensing probe is used to calibrate the toolsetting probe, rather than using a pre-calibrated artefact of known length mounted in the spindle. A stylus disc of the toolsetting probe has a pre-calibrated size or dimension, and the workpiece-sensing probe is calibrated with respect to that. This obviates the need for skilful manual calibration procedures using pre-calibrated artefacts and manual measurement tools.
1. A method of calibrating or datuming probes on a machine tool, the machine tool comprising:
a first part on which a workpiece is mountable;
a second part on which a tool is mountable, the first and second parts being movable relative to each other;
a control which controls the relative movement of the first and second parts of the machine tool;
a toolsetting probe mountable on the first part; and
a workpiece-sensing probe mountable on the second part;
the method comprising:
moving the first and second parts of the machine tool relative to each other to bring the toolsetting and workpiece-sensing probes into a sensing relationship with each other in a probing direction, a dimension or position of a first one of the probes being used to set one or more parameters of a second one of the probes in the probing direction; and
storing the one or more parameters of the second probe in the control,
wherein:
a dimension of the toolsetting probe is used to set one or more parameters of the workpiece-sensing probe,
the probing direction is an X-axis and/or Y-axis direction of the workpiece-sensing probe, and
the one or more parameters of the workpiece-sensing probe include an effective radius or diameter of a stylus tip of the workpiece-sensing probe.
2. A non-transitory computer-readable medium storing a software program for a control of a machine tool, the software program being configured to cause the control of the machine tool to perform the method according to claim 1 .
3. A control for a machine tool, comprising a memory storing a software program configured to cause the control to perform the method according to claim 1 .
4. A machine tool having the control according to claim 3 .
5. The method according to claim 1 , wherein a size of the dimension of the toolsetting probe is pre-calibrated.
6. The method according to claim 1 , wherein the dimension of the toolsetting probe is on a deflectable stylus of the toolsetting probe.
7. A method of calibrating or datuming probes on a machine tool, the machine tool comprising:
a first part on which a workpiece is mountable;
a second part on which a tool is mountable, the first and second parts being movable relative to each other;
a control which controls the relative movement of the first and second parts of the machine tool;
a toolsetting probe mountable on the first part; and
a workpiece-sensing probe mountable on the second part;
the method comprising:
moving the first and second parts of the machine tool relative to each other to bring the toolsetting and workpiece-sensing probes into a sensing relationship with each other in a probing direction, a dimension or position of a first one of the probes being used to set one or more parameters of a second one of the probes in the probing direction; and
storing the one or more parameters of the second probe in the control,
wherein:
a dimension of the toolsetting probe is used to set one or more parameters of the workpiece-sensing probe, and
a trigger signal from the workpiece-sensing probe is used to set the one or more parameters of the workpiece-sensing probe from the dimension of the toolsetting probe.
8. The method according to claim 7 , wherein a size of the dimension of the toolsetting probe is pre-calibrated.
9. The method according to claim 7 , wherein the dimension of the toolsetting probe is on a deflectable stylus of the toolsetting probe.
10. A method of calibrating or datuming probes on a machine tool, the machine tool comprising:
a first part on which a workpiece is mountable;
a second part on which a tool is mountable, the first and second parts being movable relative to each other;
a control which controls the relative movement of the first and second parts of the machine tool;
a toolsetting probe mountable on the first part; and
a workpiece-sensing probe mountable on the second part;
the method comprising:
moving the first and second parts of the machine tool relative to each other to bring the toolsetting and workpiece-sensing probes into a sensing relationship with each other in a probing direction, a dimension or position of a first one of the probes being used to set one or more parameters of a second one of the probes in the probing direction; and
storing the one or more parameters of the second probe in the control,
wherein:
a dimension of the toolsetting probe is used to set one or more parameters of the workpiece-sensing probe, and
a trigger signal from the toolsetting probe is used to set the one or more parameters of the workpiece-sensing probe from the dimension of the toolsetting probe.
11. The method according to claim 10 , wherein a size of the dimension of the toolsetting probe is pre-calibrated.
12. The method according to claim 10 , wherein the dimension of the toolsetting probe is on a deflectable stylus of the toolsetting probe.
13. A method of calibrating or datuming probes on a machine tool, the machine tool comprising:
a first part on which a workpiece is mountable;
a second part on which a tool is mountable, the first and second parts being movable relative to each other;
a control which controls the relative movement of the first and second parts of the machine tool;
a toolsetting probe mountable on the first part; and
a workpiece-sensing probe mountable on the second part;
the method comprising:
moving the first and second parts of the machine tool relative to each other to bring the toolsetting and workpiece-sensing probes into a sensing relationship with each other in a probing direction, a dimension or position of a first one of the probes being used to set one or more parameters of a second one of the probes in the probing direction; and
storing the one or more parameters of the second probe in the control,
wherein:
a dimension of the workpiece-sensing probe is used to set a datum position or offset parameter of the toolsetting probe, and
a trigger signal from the toolsetting probe is used to set the datum position or offset parameter of the toolsetting probe from the dimension of the workpiece-sensing probe.
14. The method according to claim 13 , wherein a length dimension of the workpiece-sensing probe is measured and used to pre-position the toolsetting and workpiece-sensing probes relative to each other before they are moved into the sensing relationship.
15. The method according to claim 13 , wherein the probing direction is a Z-axis direction of the workpiece-sensing probe.
16. A method of calibrating or datuming probes on a machine tool, the machine tool comprising:
a first part on which a workpiece is mountable;
a second part on which a tool is mountable, the first and second parts being movable relative to each other;
a control which controls the relative movement of the first and second parts of the machine tool;
a toolsetting probe mountable on the first part; and
a workpiece-sensing probe mountable on the second part;
the method comprising:
moving the first and second parts of the machine tool relative to each other to bring the toolsetting and workpiece-sensing probes into a sensing relationship with each other in a probing direction, a dimension or position of a first one of the probes being used to set one or more parameters of a second one of the probes in the probing direction; and
storing the one or more parameters of the second probe in the control,
wherein:
a dimension of the workpiece-sensing probe is used to set a datum position or offset parameter of the toolsetting probe, and
a trigger signal from the workpiece-sensing probe is used to set the datum position or offset parameter of the toolsetting probe from the dimension of the workpiece-sensing probe.
17. The method according to claim 16 , wherein a length dimension of the workpiece-sensing probe is measured and used to pre-position the toolsetting and workpiece-sensing probes relative to each other before they are moved into the sensing relationship.
18. The method according to claim 16 , wherein the probing direction is a Z-axis direction of the workpiece-sensing probe.