Contact Stylus Surface Roughness Profilometer

What is the Contact Stylus Surface Roughness Profilometer?

A benchtop stylus instrument with a motorized drive and inductive or laser transducer that measures 2D roughness and waviness of machined parts according to ISO 4287. It is the reference choice for Ra and Rz acceptance testing in manufacturing quality labs.

Overview

This variant combines a precision drive unit, a pickup with a diamond stylus and a column with height adjustment. The pickup uses an inductive, laser interferometer or differential transformer transducer with a measuring range of about 500 µm and resolution from 1 nm to 10 nm. Traverse lengths from 0.5 mm to 120 mm and speeds of 0.1 to 1 mm/s allow evaluation of roughness, waviness and primary profile. Software applies ISO 16610 Gaussian filters and computes up to 50 parameters including Ra, Rz, Rq, Rsk and Rmr. Stylus force is typically 0.75 mN, and tip radius is 2 µm or 5 µm with 60° or 90° cone. Skid-type and skidless pickups support surface and form work. Measurement times are under a minute per trace.

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?

• Diamond stylus with 2 µm or 5 µm tip radius and low contact force
• Inductive or laser transducer with nanometer resolution
• Traverse lengths from 0.5 mm to 120 mm with motorized positioning
• ISO 4287 and ISO 21920 parameter sets with Gaussian filtering
• Granite base and column for vibration-tolerant measurement
• Automatic calibration routine with step standards

What are the technical specifications?

A typical contact stylus surface roughness profilometer configuration offers measuring range (vertical) of ±250 µm (500 µm total), vertical resolution of 1–10 nm, traverse length of 0.5–120 mm, stylus tip radius of 2 µm or 5 µm, stylus force of 0.75 mN (adjustable) and traverse speed of 0.1–1 mm/s. 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 Contact Stylus Surface Roughness Profilometer is used in machined shaft and bore roughness, bearing and gear surface finish, casting and forging quality checks and coating thickness step measurement. 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, ISO 9001 manufacturing and Calibration traceability to national standards; 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 Contact Stylus Surface Roughness Profilometer?

Select this variant for ISO-compliant roughness on metallic and hard surfaces, where traceability and robustness matter. Avoid it for soft coatings or features smaller than the tip. In an RFQ, specify traverse length, stylus type, vertical range, required parameters, filters, and fixtures for the parts.

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.