Confocal Laser Scanning 3D Surface Profilometer

What is the Confocal Laser Scanning 3D Surface Profilometer?

A non-contact profiler that uses a scanning laser and pinhole to find the focus height at each point, giving 3D roughness of steep, rough and multi-material surfaces. It suits machined parts, textured molds and tribology samples with slopes up to about 80°.

Overview

A confocal profilometer focuses a laser spot, commonly 405 nm wavelength, through the objective while a pinhole in front of the detector blocks out-of-focus light. By scanning the spot laterally with mirrors or a spinning disk and stepping the objective vertically, the instrument finds the height of maximum intensity at each point, producing an areal map and a fully focused image. Vertical resolution is typically 1 to 10 nm, and lateral resolution about 0.15 to 0.5 µm depending on objective. Slopes up to about 70° to 85° on rough surfaces can be measured, which interferometers cannot do. Measurement is also less affected by variations in reflectivity across multi-material samples. Speed is slower than a single interferometric scan for large areas, but stitching is available.

How does it work?

A stylus profilometer drags a diamond tip, usually with a 2 µm or 5 µm radius, across the surface at a constant speed under a small force, and a transducer converts its vertical displacement to an electrical signal. The raw profile is filtered with a Gaussian filter into roughness and waviness using a cut-off wavelength such as 0.8 mm, and parameters such as Ra, Rz and Rq are calculated according to ISO 4287. Optical profilers use white-light interferometry, confocal microscopy or focus variation to determine height at each pixel by analyzing fringe contrast or sharpness while scanning vertically. They produce areal maps with parameters defined in ISO 25178, such as Sa and Sq, without touching the sample.

What are the key features?

• 405 nm laser with pinhole for optical sectioning
• Measurement of slopes up to about 85° on rough surfaces
• Fully focused color image together with height map
• Motorized XY stage with automated stitching over large areas
• ISO 25178 areal and ISO 4287 profile parameters from the same scan
• Tolerant of differing reflectivity in multi-material samples

What are the technical specifications?

A typical confocal laser scanning 3d surface profilometer configuration offers laser wavelength of 405 nm, objectives of 5×–150×, vertical resolution of 1–10 nm, lateral resolution of 0.15–0.5 µm, Z scan range of Up to 25 mm and maximum measurable slope of ≈ 85° (rough). Values are indicative of the product class; the exact figures for each configuration are confirmed on the quotation and the calibration documents supplied with the instrument.

Which applications is it used for?

The Confocal Laser Scanning 3D Surface Profilometer is used in textured mold and tool surfaces, wear scar and tribology analysis, machined and additively manufactured parts and biomedical implant surface texture. Across the wider Surface Profilometers class, laboratories also deploy it for machined part surface finish, semiconductor film step height and optical component roughness.

Which standards and certifications apply?

Relevant standards and methods include ISO 4287, ISO 21920-2, ISO 25178-2, ISO 4288 and ASTM D7127. Certification candidates for this model are CE, Laser safety Class 2 and ISO 9001 manufacturing; each is to be confirmed for the specific configuration before shipment, and certificates are supplied only where they have been issued.

Place the instrument on a vibration isolation table or heavy bench and away from drafts, since nanometer-level signals are easily disturbed. Calibrate vertical and horizontal scales with certified step-height or roughness standards at defined intervals, and check stylus wear or tip radius regularly. Clean samples before measurement and mount them level. Specify cut-off length, evaluation length and filter type in the method, because Ra depends on them. Keep stylus force low for soft materials and inspect for scratches. Optical systems need objective cleaning and periodic lateral calibration with grid standards.

How do I select the right Confocal Laser Scanning 3D Surface Profilometer?

Select this variant for rough, steep or multi-material samples that need 3D roughness without contact. Very smooth optics are better served by interferometry. In an RFQ, specify objective set, stage size, maximum slope, stitching area, parameters required and whether fully focused color images are needed.

How does it compare with other Surface Profilometers variants?

The main choice is between contact and non-contact. Stylus instruments are traceable, tolerant of steep flanks and dirt, and are the reference for ISO 4287 roughness on machined parts, but they can scratch soft surfaces and cannot reach features smaller than the tip radius. Optical profilers map areas quickly, suit delicate coatings, MEMS and films, and give 3D parameters, but struggle with transparent, very steep or highly reflective or absorbing surfaces. Consider vertical range and resolution, lateral resolution, scan length, sample size and weight, vibration isolation, software filters, and whether the work follows ISO 21920, ISO 25178 or ASTM D7127. Portable roughness testers suit shop-floor checks.