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Stylus Profilometer

The Taylor Hobson Form Talysurf PGI 1240 is a mechanical stylus profilometer for surface texture and microform measurements. Its primary purpose is for the calibration of roughness (SKU#: 15010C) and step height (SKU#: 15030C) specimens. Measurements are conducted by tracing a 2 µm spherical diamond tip across the surface. For roughness height parameters, traceability to the International System of Units (SI) unit of length is realized through a sphere with a calibrated radius (“calibration ball”). For step height, traceability is achieved using either the calibration ball or an interferometrically calibrated step height. For roughness spacing parameters, traceability is achieved by using a displacement-measuring laser interferometer to calibrate the lateral motion of the stylus.

Measurements from this instrument were used in the research, development, and production of the SRM 2460 Standard Bullet and SRM 2460a Standard Bullet Replicas. These SRMs were developed as reference standards for forensic laboratories to help verify that the equipment used to acquire images of the firearm toolmarks is operating properly and to facilitate measurement traceability and laboratory accreditation.

In addition to surface texture measurements, the Form Talysurf PGI 1240 is also capable of conducting microform measurements. This has been utilized in the calibration of microform geometric errors of the Rockwell C diamond indenter. The instrument was used to calibrate the NIST master standard Rockwell diamond indenter No. 3581 by which approximately 300 SRM 2810-2812 Rockwell C hardness (HRC) blocks were calibrated for implementation of the HRC scale in the United States.

The instrument comes equipped with software capable of calculating surface texture parameters. The Surface and Interface Metrology Group also has specialized software (Mountains Map V7) for calculating surface texture parameters (B46.1) and surface contour parameters. In addition, NIST also provides reference software and datasets for validating the values of surface texture parameters calculated by surface analysis software. We provide an interactive website, the Surface Metrology Algorithm Testing System (SMATS), that enables the user to compare our calculated parameter values with those obtained by the user's software.

The Talyor Hobson Talystep is a mechanical stylus profilometer for calibrating step height (SKU#: 15030C) specimens. It utilizes an LVDT mechanism for height detection. The instrument is extremely sensitive and has conducted calibrations of 7 nm step heights with angstrom-level uncertainties.

Stylus Profilometer
Credit: NIST
Stylus Profilometer
Credit: NIST

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Specifications/Capabilities

Taylor Hobson Form Talysurf

Horizontal Performance

 

Traverse Length – X Max / Min

200 mm / 0.1 mm

Traverse / measuring speeds

10 mm/s max -- 0.1 mm/s, 0.25 mm/s, 0.5 mm/s & 1mm/s

Data sampling interval in X

[length = measurement length]

0.125 µm [0.1 mm to 15 mm length ]

0.25 µm [ 15 mm to 30 mm length ]

1 µm [30 mm to 200 mm length]

Straightness error (Pt)

≤ 100 nm over 200 mm or ≤ 50 nm over 20 mm

Vertical Performance

 

Nominal measuring range (Z)

12.5 mm [60mm stylus arm]

Resolution (Z)

0.8 nm @12.5mm range

Stylus arm length, tip size, force

60 mm arm, 2 µm radius conisphere diamond stylus, 1 mN force

Taylor Hobson Talystep

Horizontal Performance

 

Traverse Length – X Max

2.5 mm

Traverse / measuring speeds

0.122 mm/sec, 0.0304 mm/sec, 0.00304 mm/sec

Lateral sampling interval

0.2 µm

Vertical Performance

 

Nominal measuring range (Z)

3.5 µm

RMS Noise (Z)

0.29 nm

Tip size, force

2µm radius conisphere diamond stylus, 1mN force

Created March 7, 2025