Fundamentals (#48 / #2-01-1)

Fundamentals

Accuracy requirements are becoming increasingly stringent, particularly in the area of 5-axis machining. Complex parts must be manufactured with both precision and reproducible accuracy, including over extended periods of time.

Some of the reasons for inaccuracy in multi-axis machining are deviations between the kinematic model saved in the control (see 1 in the figure) and the kinematic conditions actually existing on the machine (see 2 in the figure). When the rotary axes are positioned, these deviations cause inaccuracy of the workpiece (see 3 in the figure). It is therefore necessary for the model to approach reality as closely as possible.

The KinematicsOpt function of the control is an important component that helps you meet these complex requirements in real life: a 3D touch probe cycle measures the rotary axes on your machine fully automatically, regardless of whether they are realized as tables or spindle heads. For this purpose, a calibration sphere is attached at any position on the machine table, and measured with a resolution that you define. During cycle definition, you simply define for each rotary axis the area that you want to measure.

From the measured values, the control calculates the static tilting accuracy. The software minimizes the positioning 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 table.

Requirements

 
Machine

Refer to your machine manual.

The Adv. Function Set 1 (#8 / #1-01-1) software option must be enabled.

The KinematicsOpt (#48 / #2-01-1) software option must be enabled.

Machine and control must be specially prepared by the machine manufacturer for use of this cycle.

Requirements for using KinematicsOpt:

 
Machine

The machine manufacturer must have defined the machine parameters for CfgKinematicsOpt (no. 204800) in the configuration data.

  • maxModification (no. 204801) specifies the tolerance limit starting from which the control is to display a message if the changes made to the kinematic data exceed this limit value
  • maxDevCalBall (no. 204802) defines how much the measured radius of the calibration sphere may deviate from the entered cycle parameter
  • mStrobeRotAxPos (no. 204803) defines an M function that is specifically configured by the machine manufacturer and is used to position the rotary axes
  • The 3D touch probe used for the measurement must be calibrated.
  • The cycles can only be carried out with the tool axis Z.
  • A calibration sphere with an exactly known radius and sufficient rigidity must be attached to any position on the machine table.
  • The kinematics description of the machine must be complete and correct, and the transformation dimensions must have been entered with an accuracy of approx. 1 mm.
  • The complete machine geometry must have been measured (by the machine manufacturer during commissioning).
 
Tip

HEIDENHAIN recommends using the calibration spheres KKH 250 (ordering number: 655475-01) or KKH 80 (ordering number: 655475-03), which are particularly rigid and are designed especially for machine calibration. Please contact HEIDENHAIN if you have any questions in this regard.

Notes

 
Machine

HEIDENHAIN only guarantees the proper operation of the probing cycles if HEIDENHAIN touch probes are used.

 
Notice
Danger of collision!
During execution of touch probe cycles 400 to 499, all coordinate transformation cycles must be inactive. Otherwise, there is a danger of collision!
  1. Do not activate the following cycles before the use of touch probe cycles:
    • Cycle 7 DATUM SHIFT
    • Cycle 8 MIRRORING
    • Cycle 10 ROTATION
    • Cycle 11 SCALING FACTOR
    • Cycle 26 AXIS-SPECIFIC SCALING
  2. Reset any coordinate transformations beforehand.
 
Notice
Danger of collision!
A change in the kinematics always changes the preset as well. Basic rotations will automatically be reset to 0. There is a danger of collision!
  1. After an optimization, reset the preset

Notes about machine parameters

  • In the machine parameter mStrobeRotAxPos (no. 204803), the machine manufacturer defines the position of the rotary axes. If an M function has been defined in the machine parameter, you have to position the rotary axes to 0° (ACTUAL system) before starting one of the KinematicsOpt cycles (except for 450).
  • If machine parameters were changed through the KinematicsOpt cycles, the control must be restarted. Otherwise the changes could be lost in certain circumstances.
  • In the optional machine parameter trackAsync (no. 122503), the machine manufacturer defines whether the control orients the spindle for probing during prepositioning.