ISO programming
G451
G451
Refer to your machine manual.
This function must be enabled and adapted by the machine manufacturer.
Touch probe cycle 451 enables you to check and, if required, optimize the kinematics of your machine. Use the 3D TS touch probe to measure a HEIDENHAIN calibration sphere that you have attached to the machine table.
The control will determine the static tilting accuracy. The software minimizes the spatial error arising from the tilting movements and, at the end of the measurement process, automatically saves the machine geometry in the respective machine constants of the kinematics description.
Q parameter | Meaning |
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Q141 | Standard deviation measured in the A axis (–1 if axis was not measured) |
Q142 | Standard deviation measured in the B axis (–1 if axis was not measured) |
Q143 | Standard deviation measured in the C axis (–1 if axis was not measured) |
Q144 | Optimized standard deviation in the A axis (–1 if axis was not optimized) |
Q145 | Optimized standard deviation in the B axis (–1 if axis was not optimized) |
Q146 | Optimized standard deviation in the C axis (–1 if axis was not optimized) |
Q147 | Offset error in X direction, for manual transfer to the corresponding machine parameter |
Q148 | Offset error in Y direction, for manual transfer to the corresponding machine parameter |
Q149 | Offset error in Z direction, for manual transfer to the corresponding machine parameter |
The positioning direction of the rotary axis to be measured is determined from the start angle and the end angle that you define in the cycle. A reference measurement is automatically performed at 0°.
Specify the start and end angles in such a way that the same position is not measured twice. A duplicated point measurement (e.g., measuring positions +90° and -270°) is not advisable, but it will not generate an error message.
Start angle Q411 = –30
End angle Q412 = +90
Number of measuring points Q414 = 4
Hirth grid = 3°
Calculated stepping angle = (Q412 – Q411) / (Q414 – 1)
Calculated stepping angle = (90° - (-30°)) / (4 – 1) = 120 / 3 = 40°
Measuring position 1 = Q411 + 0 * stepping angle = –30° --> –30°
Measuring position 2 = Q411 + 1 * stepping angle = +10° --> 9°
Measuring position 3 = Q411 + 2 * stepping angle = +50° --> 51°
Measuring position 4 = Q411 + 3 * stepping angle = +90° --> 90°
To save time, you can make a rough optimization with a small number of measuring points (1 or 2), for example when commissioning the machine.
You then make a fine optimization with a medium number of measuring points (recommended value = approx. 4). Higher numbers of measuring points do not usually improve the results. Ideally, you should distribute the measuring points evenly over the tilting range of the axis.
This is why you should measure an axis with a tilting range of 0° to 360° at three measuring points, namely at 90°, 180° and 270°. Thus, define a starting angle of 90° and an end angle of 270°.
If you want to check the accuracy accordingly, you can also enter a higher number of measuring points in the Check mode.
If a measuring point has been defined at 0°, it will be ignored because the reference measurement is always done at 0°.
In principle, you can fix the calibration sphere to any accessible position on the machine table and also on fixtures or workpieces. The following factors should positively influence the result of measurement:
Position the calibration sphere on the machine table so that there can be no collisions during the measuring process.
If required, deactivate the lock on the rotary axes for the duration of the calibration. Otherwise it may falsify the results of measurement. The machine manual provides further information.
The geometrical and positioning errors of the machine influence the measured values and therefore also the optimization of a rotary axis. For this reason there will always be a certain amount of error.
If there were no geometrical and positioning errors, any values measured by the cycle at any point on the machine at a certain time would be exactly reproducible. The greater the geometrical and positioning errors are, the greater is the dispersion of measured results when you perform measurements at different positions.
The dispersion output by the control in the measurement log is a measure of the machine's static tilting accuracy. However, the measuring circle radius and the number and position of measuring points have to be included in the evaluation of accuracy. One measuring point alone is not enough to calculate dispersion. For only one point, the result of the calculation is the spatial error of that measuring point.
If several rotary axes are moved simultaneously, their error values are combined. In the worst case they are added together.
If your machine is equipped with a feedback-controlled spindle, you should activate angle tracking in the touch probe table (TRACK column). This generally increases the accuracy of measurements with a 3D touch probe.
Backlash is a small amount of play between the rotary or angle encoder and the table that occurs when the traverse direction is reversed. If the rotary axes have backlash outside of the control loop, for example because the angle measurement is performed with the motor encoder, this can result in significant error during tilting.
With input parameter Q432, you can activate backlash measurement. Enter an angle that the control uses as the traversing angle. The cycle will then carry out two measurements per rotary axis. If you take over the angle value 0, the control will not measure any backlash.
Backlash measurement is not possible if an M function for positioning the rotary axes is set in the optional mStrobeRotAxPos machine parameter (no. 204803) or if the axis is a Hirth axis.
Angle compensation is only possible with option 52 KinematicsComp.
Help graphic | Parameter |
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Q406 Mode (0/1/2/3)? Define whether the control will check or optimize the active kinematics: 0: Check the active machine kinematics. The control measures the kinematics in the rotary axes you have defined, but it does not make any changes to the active kinematics. The control displays the measurement results in a measuring log. 1: Optimize the active machine kinematics: The control measures the kinematics in the rotary axes you have defined. It then optimizes the rotary axes positions of the active kinematics. 2: Optimize the active machine kinematics: The control measures the kinematics in the rotary axes you have defined. It then optimizes angle and position errors. Software option 52, KinematicsComp, is required for compensation of angle errors. 3: Optimize the active machine kinematics: The control measures the kinematics in the rotary axes you have defined. It then automatically compensates the machine datum. It then optimizes angle and position errors. Software option 52, KinematicsComp, is required. Input: 0, 1, 2, 3 | |
Q407 Radius of calib. sphere? Enter the exact radius of the calibration sphere being used. Input: 0.0001...99.9999 | |
Q320 Set-up clearance? Additional distance between touch point and ball tip. Q320 is active in addition to the SET_UP column in the touch probe table. This value has an incremental effect. Input: 0...99999.9999 or PREDEF | |
Q408 Retraction height? 0: Do not move to any retraction height; the control moves to the next measuring position in the axis to be measured. Not allowed for Hirth axes! The control moves to the first measuring position in the sequence A, then B, then C. > 0: Retraction height in the untilted workpiece coordinate system to which the control positions the spindle axis before positioning a rotary axis. In addition, the control moves the touch probe in the working plane to the datum. Touch probe monitoring is not active in this mode. Define the positioning feed rate in parameter Q253. This value has an absolute effect. Input: 0...99999.9999 | |
Q253 Feed rate for pre-positioning? Define the traversing speed of the tool during pre-positioning in mm/min. Input: 0...99999.9999 or FMAX, FAUTO, PREDEF | |
Q380 Ref. angle in ref. axis? Enter the reference angle (basic rotation) for acquiring the measuring points in the active workpiece coordinate system. Defining a reference angle can considerably enlarge the measuring range of an axis. This value has an absolute effect. Input: 0...360 | |
Q411 Starting angle in A axis? Starting angle in the A axis at which the first measurement will be made. This value has an absolute effect. Input: –359.9999...+359.9999 | |
Q412 End angle in A axis? End angle in the A axis at which the last measurement will be made. This value has an absolute effect. Input: –359.9999...+359.9999 | |
Q413 Angle of incidence in A axis? Angle of incidence in the A axis at which the other rotary axes will be measured. Input: –359.9999...+359.9999 | |
Q414 No. of meas. points in A (0...12)? Number of measuring points the control will use to measure the A axis. If the input value = 0, the control does not measure the respective axis. Input: 0...12 | |
Q415 Starting angle in B axis? Starting angle in the B axis at which the first measurement will be made. This value has an absolute effect. Input: –359.9999...+359.9999 | |
Q416 End angle in B axis? End angle in the B axis at which the last measurement will be made. This value has an absolute effect. Input: –359.9999...+359.9999 | |
Q417 Angle of incidence in B axis? Angle of incidence in the B axis at which the other rotary axes will be measured. Input: –359.999...+360.000 | |
Q418 No. of meas. points in B (0...12)? Number of measuring points the control will use to measure the B axis. If the input value = 0, the control does not measure the respective axis. Input: 0...12 | |
Q419 Starting angle in C axis? Starting angle in the C axis at which the first measurement will be made. This value has an absolute effect. Input: –359.9999...+359.9999 | |
Q420 End angle in C axis? End angle in the C axis at which the last measurement will be made. This value has an absolute effect. Input: –359.9999...+359.9999 | |
Q421 Angle of incidence in C axis? Angle of incidence in the C axis at which the other rotary axes will be measured. Input: –359.9999...+359.9999 | |
Q422 No. of meas. points in C (0...12)? Number of measuring points the control will use to measure the C axis. If the input value = 0, the control does not measure the respective axis. Input: 0...12 | |
Q423 Number of probes? Define the number of measuring points the control will use to measure the calibration sphere in the plane. Fewer measuring points increase speed, and more measuring points increase measurement precision. Input: 3...8 | |
Q431 Preset (0/1/2/3)? Define whether the control will automatically set the active preset at the center of the sphere: 0: Do not set the preset automatically at the center of the sphere: Set the preset manually before the start of the cycle 1: Set the preset automatically at the center of the sphere before measurement (the active preset will be overwritten): Pre-position the touch probe manually above the calibration sphere before the start of the cycle 2: Set the preset automatically at the center of the sphere after measurement (the active preset will be overwritten): Set the preset manually before the start of the cycle 3: Set the preset at the center of the sphere before and after measurement (the active preset will be overwritten): Pre-position the touch probe manually above the calibration sphere before the start of the cycle Input: 0, 1, 2, 3 | |
Q432 Angular range of backlash comp.? Define the traversing angle the control will use to measure the rotary axis backlash. The traversing angle must be significantly larger than the actual backlash of the rotary axes. If input value = 0, the control does not measure the backlash. Input: –3...+3 |
NC programs contained in this User's Manual are suggestions for solutions. The NC programs or individual NC blocks must be adapted before being used on a machine.
Some NC programs depend on the machine kinematics. Adapt these NC programs to your machine kinematics before the first test run.
In addition, test the NC programs using the simulation before the actual program run.
With a program test you determine whether the NC program can be used with the available software options, the active machine kinematics and the current machine configuration.
11 TOOL CALL "TOUCH_PROBE" Z | ||
12 TCH PROBE 450 SAVE KINEMATICS ~ | ||
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13 TCH PROBE 451 MEASURE KINEMATICS ~ | ||
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Depending on the machine kinematics for correctly determining the angles, HEIDENHAIN recommends performing the measurement once with an inclination angle of 0°.
NC programs contained in this User's Manual are suggestions for solutions. The NC programs or individual NC blocks must be adapted before being used on a machine.
Some NC programs depend on the machine kinematics. Adapt these NC programs to your machine kinematics before the first test run.
In addition, test the NC programs using the simulation before the actual program run.
With a program test you determine whether the NC program can be used with the available software options, the active machine kinematics and the current machine configuration.
11 TOOL CALL "TOUCH_PROBE" Z | ||
12 TCH PROBE 451 MEASURE KINEMATICS ~ | ||
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After running Cycle 451, the control creates a log (TCHPRAUTO.html) and saves it in the folder that also contains the associated NC program. This log contains the following data: