Instrument performance testing

Here’s a common challenge: your vendors and/or customers are using different equipment to verify part quality…and their results conflict. How can you determine which system is “correct?”

Here’s another common issue: you have a new measurement requirement, but you’re not sure which instrument can do the job best. Vendors give you specs, and even demos, but it’s still hard to determine the “winner” for the given application.

An impartial third party

Digital Metrology has been helping customers deal with these types of issues for, literally, decades. We’ve seen virtually every type of surface measurement system, which lets us be unbiased (and brutally honest!) about what a system can do, can’t do, and sometimes shouldn’t do.

You can take advantage of our expertise when you’re:

• buying a new gage
• developing a new process measurement
• comparing results with vendors and customers
• addressing a disagreement between systems
• determining whether a system’s performance has changed over time.

Our job is to provide an unbiased assessment of how equipment, techniques, and parameters serve a particular quality requirement. We give you data so you can determine the best options and make the best comparisons.

Instrument manufacturers even trust us to see how their systems stack up against the competition!

Siemens stars like these can help compare lateral resolution between two systems.

A library of reference surfaces—and the expertise to use them

Comparing systems always starts with a reference surface that everyone can trust. References are expensive, though, and it’s not always practical for companies to purchase them.

Digital Metrology has strategically collected a library of reference specimens over the years that we use to compare and validate results. We have years of measurement experience to know how to use them most effectively, and to know how to separate the surface from the measurement system errors. It can be a subtle business—and it’s how we give our customers an unbiased, data-based assessment of their measurements and equipment.

Here is a selection of our reference specimens and aids:

NPL Areal Standard

Multiple surface geometries including steps, grids and Siemens stars

Uses: Optical (3D) instrument testing

Taylor Hobson 3-Line and Roughness

Calibrated groove depths and triangular roughness waveform in glass

Uses: Stylus (2D) and Optical (3D) testing

Rupert Type D Specimens

Type-D (random) texture. Nominal Ra values: 0.03, 0.1, 0.25 μm

Uses: Stylus (2D) and Optical (3D) testing

Halle Type D Specimens

Type-D (random) texture. Nominal Ra values: 0.2, 0.5, 1.5 μm

Uses: Stylus (2D) and Optical (3D) testing

Optical Flats

Various sizes

Uses: Stylus (2D) and Optical (3D) testing.

“Chirp” Specimens

Chirp waveform for lateral resolution and slope sensitivity evaluation

Uses: Stylus (2D) and Optical (3D) testing

Rubert 513 Specimen

Calibrated groove depths

Uses: Stylus (2D) and Optical (3D) testing

Opti-Cal Areal Standard

Multiple surface geometries including chirps, concentric circles, 3D-Type D and Siemens stars

Uses: Optical (3D) testing

Halle Type-D Specimens

Technovit 3040 replicated Halle Type-D specimens exhibiting microporosity with roughness values ranging from Ra: 0.5-1.5 μm.

Stylus (2D) and Optical (3D) testing

MoldTech Roughness Comparators

Plastic surfaces for visual, optical and stylus-based measurements. 90 different textures of varying roughness and geometry

Uses: Surface comparison

GAR S-22 Roughness Comparator

Comparator surfaces representing various manufacturing processes. For visual, optical and stylus-based measurements

Uses: Surface comparison

GAR Blasted and EDM Comparators

Comparator surfaces representing various manufacturing processes. For visual, optical and stylus-based measurements

Uses: Surface comparison

Rubert 589 Specimen

Two surface specimen containing a Rubert 528 Sinusoid (Ra 0.5 μm) and a 529 Sinusoid (Ra 0.1 μm)

Uses: Stylus (2D) and Optical (3D) testing

Optical Flat

Axial runout and vertical straightness evaluation.

Uses: Roundness and cylindricity

Precision Hemisphere

Axial and radial runout evaluation.

Uses: Roundness and cylindricity

“Flick” Standard

Roundness calibration and gain verification

Uses: Roundness and cylindricity