UKAS Calibration Laboratory Update

Commencing on 6.05.2021 our UKAS-accredited Calibration Laboratory is now permitted to issue UKAS Calibration Certificates for Step Height calibrations of depth-measurement standards from 100 nanometers up to 1 millimeter in depth.  As of this date we are the ONLY calibration laboratory in the UK accredited for any step-height measurements greater than 50 um in depth.

Welcome to Rubert & Co Ltd.  We are world leaders in the design and manufacture of surface texture specimens and calibration standards and are UKAS accredited. Our factory and head office is located in beautiful surroundings in Cheadle near Manchester, in the UK.

Our products fall into two classes. There are first, comparison specimens, which are samples of surfaces produced by conventional machine tools, and are used for surface roughness control at every stage  during the manufacturing process – from design, through machining, assembly, testing, and quality control, whether in a workshop environment, on site, or in offices. Secondly, we produce precision reference specimens which are used to check and calibrate surface measuring instruments. This class includes specimens for 2D measuring systems such as contacting stylus instruments, and also specimens for 3D areal surface topography systems (3D areal specimens.)

In fact, we produce the world’s largest range of surface specimens offered by a single manufacturer.

All of our specimens are made using the method of nickel electroforming, which is a replicative technique exceptionally well suited to the manufacture of surface roughness specimens, since it reproduces small surface features with great fidelity.

Comparison Specimens

The measurement of surface roughness is not as straightforward as most other engineering measurements, such as length or angle or hardness; and in order to get good accuracy, expensive instruments are needed. These are often unsuitable for workshop use, where roughness of machined surfaces can usually be assessed conveniently and with sufficient reliability by means of visual and tactile (fingernail) comparison of a workpiece with a standard set of surfaces machined in the same way.

Such sets of surfaces are called roughness comparison specimens. They are simple to use, inexpensive, and hence widely used in many different applications. For our full range see Comparison Specimens.

Precision Reference Specimens

If more precise measurements of surface roughness are needed, then a more sophisticated instrument than a fingernail must be used.  Many different types of instrument are available, ranging from inexpensive workshop roughness testers to sophisticated computerised laboratory systems; and making use of different technologies for the pickup or transducer responsible for generating an electrical signal representative of the surface, such as atomic force probes or laser beams, as well as the more widely-used contacting diamond stylus method. Whichever type of instrument is used, however, it will have to be calibrated and checked before use, by means of standard reference specimens, often called calibration standards or material measures.  For our full range of these see Reference Specimens.

Step Height Grooved Specimens

We currently produce one step height specimen which has grooves of 1mm, 200um, 70um and 30um depth.

3D Areal Calibration

Our 3D areal calibration specimens include 8 physical material measures (calibration artefacts) and allows users to calibrate the important metrological characteristics of areal surface topography measuring instruments. These 3D instruments are specified in the ISO 25178 family of standards documents, currently being developed at ISO.

The specimens enable users to adopt good measurement practice, and will help users to correlate measurements of surface texture made by non-contacting optical instruments with those made by 2D contacting stylus instruments. For our full range of these see 3D calibration.