Disc stylus performance

SS - stainless steel, CER - ceramic

Bi-directional ring gauge scan test

Scanning module

(PH10 axis position)

Effective stylus reach

Actual disc stylus used:

Diameter / material

RMS data raw

RMS data filtered

SPAN data raw

SPAN data filtered

Stylus tip deflection

Data pts

SM25-3 (A0)

100 mm

Ø30 mm / CER

0.52 µm

0.5 µm

2.9 µm

2.4 µm

0.2 mm

1244

SM25-3 (A0)

120 mm*

Ø35 mm / SS

0.5 µm

0.3 µm

3.7 µm

2.3 µm

0.2 mm

885

SM25-3 (A0)

120 mm*

Ø35 mm / SS

0.4 µm

0.3 µm

2.6 µm

1.8 µm

0.2 mm

896

SM25-3 (A0)

150 mm**

Ø30 mm / CER

0.53 µm

0.48 µm

3.6 µm

2.5 µm

0.2 mm

1244

SM25-4 (A0)

200 mm

Ø30 mm / CER

0.77 µm

0.72 µm

4.5 µm

3.5 µm

0.2 mm

1244

SM25-4 (A0)

250 mm**

Ø30 mm / CER

0.77 µm

0.68 µm

4.2 µm

3.1 µm

0.2 mm

1243

* including the 20 mm extensions

** including the 50 mm extension

Renishaw has developed a lightweight 30 mm diameter disc stylus (A-5003-7098) that will enable two-dimensional scanning with SM25-1 / 2 scanning modules.  Alternatively a 12 mm diameter disc stylus (A-5000-3615) is available that can be used with SM25-1 / 2.

Test setup criteria

Test site

Renishaw UK

Styli used

Renishaw's M3 stylus range

CMM specification

U3 = 0.48 µm + L / 1000

CMM controller

Renishaw's UCC2

Probe calibration

Renishaw's third order polynomial calibration method

Data filter used

Harmonic simple cut off order = 60 UPR (undulations per revolution)

Artefacts used

Ø25 mm (nom) calibration sphere (for the ISO 10360 Part 2 / Part 4 tests)
Ø50 mm (nom) ring gauge (for the ring gauge scan tests)

Scanning speed

5 mm/s (for the ISO 10360 Part 4 and ring gauge scan tests)

Touch speed

5 mm/s (for the ISO 10360 Part 2 tests)

Back off speed

1 mm/s (for the ISO 10360 Part 2 tests)

Bi-directional scans

The effect of probe misalignment and contact friction will result in radius changes with scanning direction if a suitable calibration procedure is not used.

Mechanical hysteresis within a probe mechanism is best demonstrated by a bi-directional scan.

Therefore, Renishaw have decided to take the high integrity approach of quoting ring gauge metrology using bi-directional scan data to demonstrate the performance of the Renishaw probe and calibration method.