Manual
VMA 15.0.0 Touch Probe Manual
🔧 What This Manual Covers
This manual covers Touch Probe-specific functionality for VMA 15.0.0TP. The TP system includes ALL vision measurement capabilities from VMA 15.0.0 — including Teaching Support, Tool Suggestion, and AF Retry — PLUS physical contact measurement using a touch trigger probe. This enables true 3D measurement of cones, cylinders, spheres, and torus geometries that camera vision cannot measure. For all vision features, refer to the VMA 15.0.0 Manual.
📄 Table of Contents
Vision vs Touch Probe — When to Use Each
The VMA-TP system gives you two measurement modalities. Knowing when to use each is key to accurate, efficient measurement.
| Measurement Need | Use Vision | Use Touch Probe |
|---|---|---|
| 2D edges, circles, lines | ✓ Preferred | Possible but slower |
| Hole diameter and position | ✓ Preferred | ✓ Alternative |
| Surface height (Z) | ✓ Via AF probe | ✓ Via TP point |
| 3D cone geometry | ✕ Cannot | ✓ Required |
| 3D cylinder (axis + diameter) | ✕ Cannot | ✓ Required |
| Sphere measurement | ✕ Cannot | ✓ Required |
| Torus measurement | ✕ Cannot | ✓ Required |
| Undercuts and hidden features | ✕ Cannot | ✓ Possible with right stylus |
The touch probe physically contacts the part. This means it can measure features that the camera cannot see — internal geometries, angled surfaces, and 3D forms. The tradeoff is speed: vision measurement is much faster for 2D features.
What Changed from VMA 11.6.2TP
Of the 39 TP-specific guide files, 18 have updated content in version 15.0.0. 21 files are identical to 11.6.2TP and fully documented in the VMA 11.6.2TP manual. Here are the key changes:
Probe Calibration — New Retry Option
If automatic stylus calibration fails in version 11.6.2, you had one option: click Back and retry from the same position. In 15.0.0, you now have two paths:
- Click [Back] — retry automatic calibration from the same position
- Select [Retry manually] checkbox → click [Next] — switch to manual calibration mode
This is a significant improvement for situations where the reference sphere position or stylus configuration makes automatic calibration unreliable.
Auto Measure 3D Shapes — Updated Point Rules
Cone measurement minimum point requirement updated: minimum 6 points (3 per circumference × 2 circumferences). The distance from the first entered path point to the first measurement point now defines the standard path point distance for all subsequent path points in the measurement sequence.
TP Point — Contact Direction Compensation
The TP Point measurement tool now explicitly documents the contact direction compensation feature. When a touch trigger probe contacts a surface, the actual contact point differs slightly from the calculated measurement point depending on approach direction. This compensation corrects for that deflection error.
Hardware Settings — Back Off Distance Range
The valid range for Back Off Distance is now explicitly documented: 0.1 mm to 1.0 mm. Values outside this range are not accepted. The joystick back-off behavior checkbox is also updated with clearer documentation.
Unchanged TP Files (21 of 39)
These files are identical to VMA 11.6.2TP — refer to the VMA 11.6.2TP Manual for their content:
AppTP, BaseElementCone, BaseElementCylinder, BaseElementTorus, BaseProbeCalibInfo, BaseProbeCalibModuleSelect, BaseProbeCalibResult, BaseProbeCalibSetting, HardwareCncDlgTP, HardwareJoystickTP, KeyCCone, KeyCCylinder, KeyCTorus, ModuleChangerCalib, ModuleChangerCalibPre, ModuleChangerCalibResult, ProbeCalibInfo, ProbeCalibModuleSelect, ProbeCalibModuleShape, ProbeCalibResult, ProbeCalibSetting
Touch Probe Calibration
Why Calibration Is Critical
The touch trigger probe has physical dimensions — stylus length, ball diameter, and tip offset. These must be measured accurately before the system can convert raw contact points into corrected measurement values. Without calibration, all TP measurements will be offset by the stylus geometry.
Calibration Types
Stylus Calibration
Standard calibration for a single stylus. Measures the reference sphere to determine stylus ball center and offset. Required any time the stylus is changed.
Reference Stylus Calibration
Calibrates the reference stylus — the known-good stylus used as the calibration master. Run this first when setting up the system.
Manual Probe Calibration
Manual calibration when automatic calibration fails. Operator manually directs probe to measurement positions on the reference sphere.
Module Changer Calibration
For systems with a module changer (automatic stylus exchange). Calibrates each module position so the system knows the offset for every stylus in the carousel.
Standard Stylus Calibration Workflow
The wizard opens. Follow through the numbered steps (1 of 7 through 7 of 7).
If using a module changer, select the module/stylus to calibrate.
Specify the stylus geometry: ball diameter, stylus length, and attachment type.
The system verifies the reference sphere is in position and the probe is ready.
System takes preliminary contact points to find the approximate sphere location.
System automatically measures the reference sphere. If it fails: click [Back] to retry automatically, OR check [Retry manually] and click [Next] to take over manually. (Updated in 15.0.0)
Calibration results display — check that residual errors are within acceptable limits. Confirm to save.
3D Base Elements
TP-Only 3D Base Elements
These features can only be measured with the touch probe — camera vision cannot detect true 3D geometry in 3 dimensions.
Cone
A conical surface defined by axis direction, apex position, and half-angle. Measured by touching multiple points on two circumferences at different heights.
Cylinder
A cylindrical surface defined by axis direction and diameter. Measured by touching points on multiple cross-sections along the axis.
Sphere
A spherical surface defined by center position and radius. Measured by touching points distributed around the sphere surface.
Torus
A toroidal (donut-shaped) surface defined by major and minor radii and axis. The most complex 3D feature available.
Derived Relationships from 3D Features
Once 3D base elements are measured, you can calculate:
- Axis-to-axis distance — between two cylinder or cone axes
- Perpendicularity — between cylinder axis and a reference plane
- Coaxiality — how well two cylinders share the same axis
- Runout — variation of a surface relative to an axis
AutoMeasure 3D Wizards
Automated 3D Measurement
The AutoMeasure 3D wizards guide the system through multi-point 3D measurement sequences automatically. Rather than manually touching each measurement point, you define the geometry and the system drives the probe through the required contact sequence.
Cone AutoMeasure (Updated in 15.0.0)
Measures a cone by automatically collecting contact points on two circumferences.
- Minimum points: 6 total — 3 points on each of 2 circumferences at different heights along the axis
- Path point rule: The distance from the first entered path point to the first measurement point becomes the standard offset distance for all subsequent path points in the sequence
- Output: Cone axis direction, apex position, half-angle, and form error
Cylinder AutoMeasure
Measures a cylinder by collecting contact points on multiple cross-sections.
- Define number of cross-sections and points per cross-section
- System moves probe through the full measurement sequence automatically
- Output: Axis direction, axis position, diameter, straightness, cylindricity
Sphere AutoMeasure
Measures a sphere by distributing contact points across the surface.
- Define number of measurement points and distribution pattern
- System drives through the sequence automatically
- Output: Center position (X,Y,Z), diameter, sphericity
Setting Up a 3D AutoMeasure
The 3D AutoMeasure tools are available in Teaching mode from the Measurement Tool menu.
Measurement Tool → Auto Measurement → [Cone / Cylinder / Sphere]
Define a safe approach point near the measurement start position. This tells the system where to position the probe before beginning the contact sequence.
Set number of points, cross-section positions (for cylinder/cone), and approach speed.
Run the sequence. Review the measured values and residual errors. Adjust point count or positions if errors are too large.
TP Point Measurement
What Is TP Point?
The TP Point measurement tool measures a single point on a surface using the touch trigger probe. It returns the X, Y, and Z position of the contact point, corrected for probe deflection.
Contact Direction Compensation (Updated in 15.0.0)
When the touch trigger probe contacts a workpiece, the probe tip deflects slightly before triggering. The actual trigger point is not exactly at the surface — it is offset by the probe deflection in the contact direction. Without compensation, this creates a systematic position error.
The compensation works by specifying the contact direction (axis) for the workpiece in the local coordinate system. The software then applies the known stylus ball radius and deflection model to calculate the corrected surface point.
- [Compensation] setting: Set the contact direction (±X, ±Y, ±Z) for each TP Point measurement tool
- The system corrects the raw contact point to the true surface position
- This reduces systematic error from probe deflection
TP Hardware Settings
Back Off Settings
After the probe contacts the workpiece and triggers, it must retract before moving to the next position. The Back Off settings control this retraction.
| Setting | Valid Range | Description |
|---|---|---|
| Back off distance | 0.1 mm to 1.0 mm | How far the probe retracts after contact before moving to the next position |
| Back off during joystick use | Checkbox | When checked, probe retracts by the back off distance after each contact during joystick-driven measurement |
| Overtravel distance | Configurable | Maximum allowable probe travel past the trigger point before an error is raised |
CNC Settings for TP
The TP hardware settings include CNC speed and acceleration parameters for probe movement. These control how fast the stage moves during probe approach and retraction. Lower speeds improve measurement accuracy; higher speeds improve throughput. Set these based on your part fragility and accuracy requirements.
Joystick Settings for TP
Joystick button assignments for TP operation can be configured from Hardware Settings → TP → Joystick Button Settings. You can assign probe contact, retraction, and navigation functions to specific joystick buttons for efficient manual measurement operation.
AF Retry Settings
VMA-TP 15.0.0 includes the same Vision AF and Laser AF Retry Settings as VMA 15.0.0. These apply to vision probes used in TP recipes — the TP system uses both vision and touch measurement, and vision probes can also fail during replay.
Key-In 3D Elements
What Is Key-In?
Key-In elements allow you to manually enter known nominal geometry as a base element — without actually measuring it. This is useful when you know the theoretical geometry of a feature (from a drawing) and want to use it as a reference for other calculations.
Key-In 3D Elements Available
| Element | Parameters to Enter | Common Use |
|---|---|---|
| Cone | Axis direction, apex X,Y,Z, half-angle | Reference cone for runout or coaxiality calculation |
| Cylinder | Axis direction, axis point X,Y,Z, diameter | Nominal bore axis for perpendicularity check |
| Torus | Axis direction, center X,Y,Z, major radius, minor radius | Theoretical reference for torus form error |
Common Gotchas
| Problem | Cause | Fix |
|---|---|---|
| 3D measurements consistently offset | Stylus not calibrated after change | Recalibrate stylus — always after any stylus change |
| Automatic calibration fails | Reference sphere mispositioned or stylus geometry mismatch | Use new retry options: [Back] to retry auto, or [Retry manually] + [Next] for manual |
| Cone measurement rejects fewer than 6 points | Minimum point requirement (3 per circumference × 2) | Ensure at least 6 contact points are programmed |
| TP Point results show systematic offset | Contact direction compensation not set or set incorrectly | Set compensation direction to match actual probe approach direction |
| Back off distance setting rejected | Value outside 0.1–1.0 mm valid range | Enter a value between 0.1 and 1.0 mm |
| Probe crashes into part | Path point too close; back off too small | Increase back off distance; add more path points away from the part |
| Module changer selects wrong stylus | Module changer calibration out of date | Run Module Changer Calibration for all modules |
| Vision probes fail during TP recipe replay | Probe detection failure | Enable Vision AF / Laser AF Retry Settings for affected probes |
C:\ProgramData\NEXIVAutoMeasure\ on your machine. Visit our Downloads page for organized access.