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Diamond styli for metrology applications

Renishaw OPTiMUM™ diamond styli support high performance scanning for the toughest environments. Benefit from increased working life and reduction in recalibration and inspection downtime.

Why use OPTiMUM diamond coated styli?

The OPTiMUM diamond styli range has been specifically developed for use within metrology applications that require a hard-wearing stylus.

The principal advantage of its diamond coated spheres is that they will maintain their roundness and will not suffer material ‘pick up' or premature wear when scanning soft alloys or abrasive materials.

This provides multiple benefits including an increased working life, and reduction in recalibration and inspection downtime.

Watch our OPTiMUM diamond styli in action


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Designed to order, your diamond coated styli can be made in a variety of thread sizes and stem materials.

With ball sizes from 1 mm up to 8 mm, we will work with you to find a solution to your metrology concerns.

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Find out how OPTiMUM diamond styli can benefit you

In most inspection challenges, the choice of stylus is critical. Access to workpiece features, inspection times and probe performance are all influenced by the stylus used.

The principal advantage of our diamond coated spheres is that they will maintain their roundness and will not suffer material pick up or premature wear when scanning abrasive materials or soft alloys. This provides multiple benefits including an increased working life, and reduction in recalibration and inspection downtime.

The Renishaw styli range is comprehensive. Please refer to our precision styli for metrology page for more information.

OPTiMUM™ diamond stylus scanning silicon carbide
OPTiMUM™ diamond stylus scanning an aluminium Cosworth V10 engine block with a steel cylinder lining

Avoid premature stylus wear

Scanning on hard or abrasive surfaces can result in abrasive wear from interaction between the workpiece and stylus ball materials.

When using a ruby ball for scanning, minute particles of residue from the workpiece surface can cause fine scratches on the stylus ball and the surface of the workpiece.

The balls on OPTiMUM diamond styli are extremely wear resistant and retain their form after scanning on abrasive surfaces.

No material build-up

Scanning on soft surfaces, such as aluminium, creates material build-up on the stylus ball.

When a ruby ball is used to scan aluminium, the two materials are attracted to each other and material is passed from the softer surface to the harder surface. This means that aluminium is deposited on the surface of the ruby ball, changing the shape of the ball and meaning that your stylus will need to be changed frequently.

With OPTiMUM diamond styli, material build-up does not adhere to the ball and any small deposits can simply be wiped off.

Challenging perception around material testing. What do we really know?

We have many types of stylus ball materials available, but do we really know which material performs best when scanning?

At Renishaw, it is vital that our customers are using the correct stylus in their scanning applications and that is why material testing is so important to us.

Our team keep busy, conducting trials on well known, problem materials. If you are having problems scanning any particular material, our in-house experts can help.

Are you suffering pick up or wear issues when scanning titanium?

We performed scanning trials on a Ti64 titanium alloy with a standard turned finish.

This was a continuous 5000-metre test using ruby, silicon nitride and OPTiMUM diamond tip styli. A single point scan with Z point measurement every 50 metres, to determine whether pick up or wear is occurring.

The results confirm that ruby and OPTiMUM diamond styli were the best options with results within the CMM's expected performance specification. Silicon nitride started to show low levels of wear from the start that continued throughout the test.

Under these test conditions we would recommend both ruby and OPTiMUM diamond styli as an acceptable scanning solution.

Scanning trials on Ti64 titanium alloy

Having problems scanning anodised aluminium?

In our quest to challenge perception, sweep scanning trials have been conducted on extruded, machined and AA15 anodised 6082 aluminium alloy.

This was a continuous 5000-meter test using ruby, silicon nitride and OPTiMUM diamond tip styli. A single point scan with Z point measurement every 50m to determine whether pick up or wear was occurring.

All three materials performed well over this distance; slight wear was seen on the silicon nitride but was well within the CMM's expected performance specification.

Under these test conditions, we would recommend ruby, silicon nitride or an OPTiMUM diamond tip styli as an acceptable scanning solution.

Scanning trials on anodised aluminium

Having problems with pickup on aluminium 6082-T6?

We performed sweep scanning trials on aluminium 6082-T6.

This was a continuous 15000-meter test using ruby, silicon nitride and OPTiMUM diamond tip styli. A single point scan with Z point measurement every 50m to determine whether pick up or wear was occurring.

With our OPTiMUM diamond tip styli, we saw phenomenal scanning performance, with no change in metrology and no pickup.

Under these test conditions, we would recommend OPTiMUM diamond tip styli as the only acceptable scanning solution.

Styli Scanning trials on Aluminium 6082-T6

Custom design

Diamond coated styli are designed to order and can be made in a variety of thread sizes and stem materials. Ball sizes vary to suit your specific needs, from 1 mm up to 8 mm.

OPTiMUM diamond styli are designed and produced in house by Renishaw, ensuring short lead-times and high standards of quality.

All OPTiMUM diamond styli produced for use with the REVO® RSP2 scanning probe are tested by Renishaw to guarantee the REVO system tuning parameters for controlling resonance are valid for the styli.

Wear comparison testing between Renishaw OPTiMUM diamond styli and the standard ruby equivalent

White paper: OPTiMUM diamond styli

Read our white paper on the comparison between the OPTiMUM diamond styli and the industry-standard ruby styli, to demonstrate the difference in wear under extreme scanning conditions.

Download white paper