Integrating fixtures into collision monitoring (#140 / #5-03-2)

Application

The Set up fixtures function determines the position of a 3D model in the Simulation workspace, matching the real fixture in the machine envelope. Once the fixture has been set-up, the control considers it in Dynamic Collision Monitoring (DCM).

Requirements

  • If you are using a HEIDENHAIN touch probe with EnDat interface, then the Touch Probe Functions software option (#17 / #1-05-1) is automatically enabled. Calibrating the workpiece touch probe
  • If you are using a HEIDENHAIN touch probe with EnDat interface, then the Touch Probe Functions software option (#17 / #1-05-1) is automatically enabled.

  • Collision Monitoring v2 (#140 / #5-03-2) software option
  • Workpiece touch probe
  • Permitted fixture file matching the real fixture
  • Options for fixture files

Description of function

The Set up fixtures function is available as a touch probe function in the Setup application of the Manual operating mode.

The Set up fixtures function determines the fixture position using various probing processes. First, one point on the fixture is probed in every linear axis. The position of the fixture is defined in this way. After probing one point in all linear axes, further points can be integrated in order to improve positioning accuracy. After defining the position in one axis direction, the control changes the status of that axis from red to green.

The error estimate diagram shows the estimated distance of the 3D model from the real fixture for each probing point.

Error estimate diagram

The scope of the Set up fixtures function depends on the Adv. Function Set 1 (#8 / #1-01-1) and Adv. Function Set 2 (#9 / #4-01-1) software options as follows:

  • Both software options enabled:
  • You can tilt before probing, and incline the tool while probing, in order to probe even complex fixtures.

  • Only Adv. Function Set 1 (#8 / #1-01-1) is enabled:
  • You can tilt before probing. The working plane must be consistent. If you move the rotary axes between the touch points, the control will display an error message.

  •  
    Tip

    If the current coordinates of the rotary axes and the defined tilt angles (3D ROT window) match, the working plane is consistent.

  • None of the two software options is enabled:
  • You cannot tilt before probing. If you move the rotary axes between the touch points, the control will display an error message.

Tilting the working plane (#8 / #1-01-1)

Compensating the tool angle of inclination with FUNCTION TCPM (#9 / #4-01-1)

Extension of the Simulation workspace

In addition to the Probing function workspace, the Simulation workspace offers graphic support for setting up the fixture.

The Set up fixtures function with the Simulation workspace open

When the Set up fixtures function is active, the Simulation workspace shows the content below:

  • Current position of fixture as viewed by the control
  • Probed points on the fixture
  • Possible direction of probing by means of an arrow:
    • No arrow
    • Probing is not possible. The workpiece touch probe is too distant from the fixture or the workpiece touch probe is positioned within the fixture, as seen by the control.

    • In this case, you can adjust the position of the 3D model in the simulation, if applicable.

    • Red arrow
    • Probing in the direction of the arrow is not possible.

    •  
      Tip

      Probing on edges, corners or heavily curved fixture areas fails to deliver precise measuring results. This is why the control blocks probing in these areas.

    • Yellow arrow
    • Probing in the direction of the arrow is possible under certain conditions. Probing is done in a deselected direction or might cause collisions.

    • Green arrow
    • Probing in the direction of the arrow is possible.

Icons and buttons

The Set up fixtures function contains the following icons and buttons:

Icon or button

Meaning

XY Clamping plane

This selection menu defines the plane in which the fixture is in contact with the machine.

The control offers the following planes:

  • XY clamping plane
  • XZ clamping plane
  • YZ clamping plane
 
Tip

Depending on the selected clamping plane, the control displays the corresponding axis directions. In the XY Clamping plane, for example, the control displays the axes X, Y, Z and C.

Name of fixture file

The control automatically saves the fixture file in the initial folder.

The fixture file name can be edited before saving.

Shifts the position of the virtual fixture by 10 mm, 0.3937 inch, or 10° in the negative axis direction

 
Tip

Fixtures are shifted by mm or inch units in a linear axis and by degrees in a rotary axis.

Shifts the position of the virtual fixture by 1 mm, 0.0394 inch, or 1° in the negative axis direction

  • Enter the position of the virtual fixture directly
  • Value and estimated accuracy after probing

Shifts the position of the virtual fixture by 1 mm, 0.0394 inch, or 1° in the positive axis direction

Shifts the position of the virtual fixture by 10 mm, 0.3937 inch, or 10° in the positive axis direction

Status of the axis:

  • Dimmed
  • The axis direction is deselected for this set-up process and will not be taken into account.

  • Empty
  • No probing points have been determined yet.

  • Red
  • The control cannot determine the fixture position in this axis direction.

  • Yellow
  • The position of the fixture in this axis direction already contains information. The information is not meaningful yet.

  • Green
  • The control can determine the fixture position in this axis direction.

Save and activate

This function saves all obtained data in a CFG file and activates the measured fixture in Dynamic Collision Monitoring (DCM).

 
Tip

When using a CFG file as the data source for the measuring process, the existing CFG file can be overwritten by Save and activate at the end of the measuring process.

When creating a new CFG file, enter a different file name next to the button.

When using a datum clamping system and for this reason you do not want to consider one axis direction (such as Z) when setting up the fixture, the axis in question can be deselected by a toggle switch. The control will not take deselected axis directions into account in the set-up process and positions the fixture by considering the remaining axis directions only.

Error estimate diagram

Every probing point further restricts the possible positioning of the fixture and puts the 3D model closer to the actual position in the machine.

The error estimate diagram shows the estimated distance of the 3D model from the real fixture for each probing point.

Error estimate diagram of the Set up fixtures function with transparent columns

The error estimate diagram of the Set up fixtures function displays the following information:

  • Error estimate [mm]
  • This value indicates the greatest estimated distance between the 3D model and the fixture after each probing point.

  • Mean deviation (RMS)
  • This value indicates the average of all measured distances between the 3D model and the fixture.

  • Deviation [mm]
  • On this axis, you can see how great the estimated distance between the 3D model and the probing point at the fixture is.

  • No. of probe point
  • This axis shows the number of probing points.

  • Columns
  • If the status is not yet green for all axes, the control will display transparent columns.

  • After each probing point, the control will adjust the 3D model accordingly. This means that the previous values will change, too.

  • Once the columns in the error estimate diagram are no longer transparent and the Error estimate [mm] value displays the required precision, the set-up process is completed.

The factors below influence the accuracy that can be achieved when measuring fixtures:

  • Accuracy of workpiece touch probe
  • Repeatability of workpiece touch probe
  • Accuracy of 3D model
  • Condition of the actual fixture (e.g., existing wear or score marks)

Example of sequence of fixture probing points

Below are some of the probing points that can be set for different fixtures:

Chucking equipment/fixtures

Possible sequence

Probing points for a vise with a fixed vise jaw

The following probing points can be set when measuring a vise:

  1. Touching the fixed vise jaw in Z–
  2. Touching the fixed vise jaw in X+
  3. Touching the fixed vise jaw in Y+
  4. Touching the second value in Y+ for rotation
  5. To improve accuracy, touching the check point in X–
Probing points with a three-jaw chuck

The following probing points can be set when measuring a three-point chuck:

  1. Touching the jaw chuck body in Z–
  2. Touching the jaw chuck body in X+
  3. Touching the jaw chuck body in Y+
  4. Touching the jaw in Y+ for rotation
  5. Touching the second value at the jaw in Y+ for rotation

Measuring the fixed-jaw vise

 
Tip

The desired 3D model must meet the requirements of the control.

Options for fixture files

To measure a vise using the Set up fixtures function:

  1. Affix a real vise in the working space

  1. Select the Manual operating mode

  1. Insert the workpiece touch probe
  2. Manually position the workpiece touch probe above the fixed vise jaw at a notable point
  3.  
    Tip

    This step makes the subsequent steps easier.

  1. Select the Setup application

  1. Select Set up fixtures
  2. The control opens the Set up fixtures menu.

  1. Select a 3D model matching the real vise

  1. Select Open
  2. The control opens the selected 3D model in the simulation.

  1. Pre-position the 3D model by using the buttons for the individual axes within the virtual working space
  2.  
    Tip

    For pre-positioning the vise, use the workpiece touch probe as a point of reference.

    At this point in time, the control does not know the precise position of the fixture, but of the workpiece touch probe. Pre-positioning the 3D model in accordance with the position of the workpiece touch probe and by using, for example, the table's T-slots produces values close to the position of the real vise.

    Even after recording the first measuring points, the shifting functions are still available for correcting the fixture position manually.

  1. Specify the clamping plane (e. g., XY)
  2. Position the workpiece touch probe until a green down arrow appears
  3.  
    Tip

    As the 3D model is only pre-positioned at this point in time, the green arrow cannot provide any reliable information about whether the desired surface of the fixture will actually be touched. Check if the fixture position in the simulation and in the machine match and if touching in the direction of the arrow is possible on the machine.

    Do not touch directly near edges, chamfers and roundings.

  1. Press the NC Start key
  2. The control probes in the direction of the arrow.
  3. The control displays the status of the Z axis in green and shifts the fixture to the touched position. The control marks the touched position by a point in the simulation.

  1. Repeat this process in axis directions X+ and Y+
  2. The status of the axes turns green.

  1. Touch another point in axis direction Y+ for the basic rotation
  2.  
    Tip

    To achieve maximum accuracy when touching the basic rotation, the probing points should be as far apart from one another as possible.

  3. The control changes the status of the C axis to green.

  1. Touch the check point in axis direction X–
  2.  
    Tip

    Additional check points at the end of the measuring process improve the matching accuracy and minimize the faults between the 3D model and the real fixture.

  1. Select Save and activate
  2. The control closes the Set up fixtures function, saves a CFG file with the measured values at the path specified above, and integrates the measured fixture into Dynamic Collision Monitoring (DCM).

Notes

 
Notice
Danger of collision!
To probe the clamping situation in the machine exactly, the workpiece touch probe must be properly calibrated and the value R2 properly defined in the tool management. Otherwise, incorrect tool data of the workpiece touch probe may cause inaccurate measurement and possibly a collision.
  1. Calibrate the workpiece touch probe at regular intervals
  2. Enter parameter R2 in the tool management
  • The control cannot identify modeling differences between the 3D model and the real fixture.
  • At the time of set-up, Dynamic Collision Monitoring (DCM) does not know the exact position of the fixture. In this condition, collisions with the fixture, the tool or other non-machine components such as fixing clamps in the work envelope may occur. The non-machine components can be modeled on the control using a CFG file.
  • Editing CFG files with KinematicsDesign

  • If you cancel the Set up fixtures function, DCM will not monitor the fixture. In this case, any fixtures previously set up are also removed from the scope of monitoring. The control displays a warning.
  • Only one fixture can be measured at a time. To monitor several fixtures simultaneously by DCM, the fixtures must be integrated into a CFG file.
  • Editing CFG files with KinematicsDesign

  • When measuring a jaw chuck, the coordinates of the axes Z, X and Y are determined just as when measuring a vise. The rotation is determined from one single jaw.
  • Use the +, -, *, /, (, and ) keys for calculations in the numerical input fields.
  • The saved fixture file can be integrated into the NC program with the FIXTURE SELECT function. This can be used for simulating and executing the NC program, considering the real setup situation.
  • Load and remove fixtures with the FIXTURE NC function