Introduction
Buying an optical profiler is easy to get wrong. Datasheets look alike while they are not, demos are run on ideal samples, and the questions that decide whether a system works in your lab or on your shop floor are often asked too late.
This guide provides some aspects that we often find as very relevant and helps to ensure having a sustainable fitting profiler for the R&D, quality or production departments. While there are many aspects, those are the ones we would like to emphasize:
- Measurement tasks on samples
- Size of components to be measured
- Metrology performance and the data sheet challenge
- Different user demands
Check 1: What do you need to measure?
- depending on those a macro or micro profiler fits better
Why this comes first: it is the single most important question. Roughness, flatness, parallelism, step height, layer thickness, form deviation and microstructure geometry lead to different system families. Answering it immediately separates microscope-based systems (small fields, high lateral detail) from large-area systems (form and flatness on bigger parts) — and saves you from evaluating instruments that were never a fit.
Check 2: How large are your parts?
- this is mainly about field of view and stitching quality
Why it matters: with larger parts, systems that look identical on paper behave very differently in practice. The trap: "measuring range" figures hide two separate questions — how tall your part can be, and how wide an area you can measure at full quality.
- Tall parts / Z-resolution
Watch out: full resolution along the whole Z-range?
Verify two things: the travel range of the Z-axis, and — the part most datasheets stay quiet about — whether the system delivers its full, constant measurement resolution along that entire range. Some systems only reach their specified resolution within a fraction of the Z-travel. Ask explicitly: "At which Z-positions does your resolution spec apply?"
- Wide parts / stitching quality
Watch out: field of view — and what happens beyond it
If your measurement area is wider than the field of view, the system must stitch multiple fields — and stitching quality is where large-area measurements quietly fail. Good stitching needs a rigid mechanical design and superior software. Ask every vendor to show stitching residuals on a real part, not a demo sample.
Depending on the system, Polytec profilers offer a Z-range of 70 to 100 mm — with full measurement resolution along the entire Z-axis, not just a segment of it.
For wide parts, True Stitching extends the measuring area to 230 × 220 mm and beyond with documented, audit-ready residuals. In an independent comparison at one of Germany's top technical universities, the stitching results of five known manufacturers were evaluated side by side — the institute was convinced by True Stitching and purchased the Polytec system.
Check 3: What metrology performance is provided?
- challenge is the data sheet comparison, as they can mislead
Our profiler deliver top-tier resolution and repeatability, and we can quote impressive numbers for the performance. But instead of stating best case figures, Polytec decided to utilize the Fair Data Sheet Initiative to provide the best comparability for customers.
The trap: resolution comparison is the classic failure point of optical metrology purchasing. The typical approach — collect datasheets, build a comparison table — fails because every manufacturer defines their own measurement conditions for the values they publish. Two "0.1 nm" claims can describe entirely different real-world performance.
Ask for the fair data sheet
Request specifications according to standardized, harmonized measurement conditions (a “fair data sheet”). Values determined under defined, comparable conditions give you a far more stable basis for comparison than marketing numbers. Any vendor confident in their instrument will provide them — hesitation is a data point too.
Test the system — don’t read about it
The resolution and repeatability you will actually achieve depends on your parts, your environment and your operators. The only reliable proof: a feasibility study on your own samples, or better yet, renting the system and running it with your team, in your environment, across your range of parts — before any purchase decision.
“We offer both, deliberately: a free feasibility study — you send parts, our application engineers measure them and you receive the full data — and rental systems (PolyRent) that prove themselves in your own process. We’d rather win on your measurement results than on a datasheet.”
Check 4: Who will operate it and where?
- it is about simplicity, deep dive ability and repeatability
Why it matters: a system that only a metrology specialist can operate becomes a bottleneck the day it moves near production. Before comparing instruments, be honest about the environment (climate-controlled lab, at-line, shop floor,..) and the operators (metrology engineers, (un-)trained production staff).
- Usability
Watch out: expert instrument or push-button workflow?
Check whether recurring measurements can be stored as recipes and started by non-specialists with a single action — including automatic evaluation and pass/fail output. Ask for a live demo where your colleague, not the vendor's application engineer, runs the measurement.
- Automation & environment
Watch out: lab instrument in disguise?
Many optical profilers are laboratory instruments that struggle with vibration and temperature on a shop floor. If production use is on your roadmap — even years out — check robustness and automation interfaces (MES/PLC) now. Retrofitting is expensive; replacing is worse.
Polytec systems are built for production, not just the lab: rugged design with few moving parts, Environmental Compensation against vibration, and MES/PLC interfaces for integration. Our new Sherpa software guides operators through recipe-based measurements — from single-button workflows for production staff to full analytical depth for metrology experts.
And the platform is modular: start at-line, grow toward in-line without replacing the system.
Summary and recommendation
The above stated "checks" for identifying the best fitting profiler are important but only some of many others topics (ease of use, pricing,...). As often stated, our recommendation is to test profiler in real life and with challenging samples.
For us at Polytec we want to support you by offering a free feasibility study or our PolyRent - meaning you can rent a system and deduct the price from a potential purchase. But the first recommend step is to have a talk with our experts to dive into your metrology tasks.