RESONIKS raises seed funding to scale AI acoustic quality control — QCFlex makes defect detection plug-and-play for any factory

Imagine tapping a metal part and listening. A defect-free casting rings clearly; one with an internal crack or air pocket sounds subtly different — imperceptible to the human ear, but precisely readable by a trained AI. That is the core idea behind RESONIKS, a Dutch-Finnish deeptech startup that has spent three years turning this principle into a deployable industrial product.

The company has closed a new seed round led by SHIFT Invest, a Dutch impact VC, co-led by returning investor Kvanted Ventures — the Finnish industrial tech fund that led RESONIKS’ first round in 2024. Angel investor Frank Höcker, founder of PRESTO and Höcker Polytechnik, also participated. The funding will accelerate the rollout of QCFlex, RESONIKS’ standalone acoustic QC system, across European manufacturing — with a primary focus on Germany’s automotive and mechanical engineering sectors.

The technology: acoustic resonance meets AI

Non-destructive testing (NDT) — inspecting metal components for defects without damaging them — is critical in manufacturing safety-critical parts for automotive, aerospace, and maritime applications. Traditional NDT methods are slow, dependent on increasingly scarce skilled technicians, and prone to inconsistency.

RESONIKS’ approach is built on a patented modal analysis technique. An impact strikes the metal part, causing it to resonate at its natural frequencies. A microphone captures those vibrations. An AI algorithm then analyses the acoustic signature and determines with high precision whether the part is defect-free or contains internal flaws — cracks, pores, air pockets — that would be invisible to both the human and machine eye.

“It’s like a guitar,” explains CEO Felix Wassmann. “We hit a part to make it resonate in its own frequencies, then pick up those vibrations using a microphone. The AI distinguishes between parts that are defect-free and those that are not — detecting flaws that current methods often miss.”

In independent comparative testing, RESONIKS was the only system to correctly classify all ten tested parts — outperforming every other NDT method in the evaluation. As one customer noted: “RESONIKS was the only company to correctly classify all ten parts, demonstrating superior sensitivity and defect detection compared to all other tested methods.”

QCFlex: plug in anywhere, no rebuilding required

The product at the centre of this funding round is QCFlex — a standalone acoustic quality control system designed to integrate at any point in an existing manufacturing line without disruption. Unlike systems that require deep architectural integration, QCFlex supports both in-line monitoring and standalone end-of-line inspections. Manufacturers can start with a specific bottleneck and expand from there.

Setup is frictionless: one to thirty sensors are positioned around the metal part — small or large — and the system manages the rest via a touchscreen interface. No radiation, no chemicals, no specialist operator required. The philosophy mirrors what we’ve seen work in other European industrial infrastructure plays — meet manufacturers where they are, rather than asking them to rebuild around your product. (RESONIKS’ approach to acoustic defect detection is conceptually related to the sensor-based quality intelligence platforms also emerging in food safety — NanoStruct raised €2.6M this week to detect pathogens in food manufacturing using nanostructured sensor chips.)

From coffee cans to metal castings: the founding story

The RESONIKS origin story has a revealing detail. The three founders initially built a smart coffee can — a consumer IoT product that would alert users when it ran low. After doing market research and finding thin margins and complex logistics, they pivoted to B2B and stumbled across containers holding titanium powder: highly reactive material where knowing what’s inside without opening the container was a critical industrial challenge. That led them to acoustic sensing, which led them to metal defect detection, which led them to the company they are today.

The rebrand from their original name SUPPLYZ to RESONIKS — a portmanteau of “resonance” and “Akustik” (German for acoustics) — marked the point where the company committed fully to this focus. It was the right call: RESONIKS went on to win the VDMA Startup Award 2025, chosen by over 600 senior decision-makers at Europe’s largest mechanical engineering association.

A European company with a German growth thesis

RESONIKS operates from three locations: The Hague (Netherlands), Tampere (Finland), and Munich (Germany). The Munich presence is strategic — Germany’s automotive and mechanical engineering clusters represent the densest concentration of metal manufacturing customers in Europe.

The company was built through YES!Delft, one of Europe’s top deeptech accelerators, and supported by EIT Manufacturing and the TechFounders programme. It is already deployed across multiple factories in Europe. The roadmap is ambitious: Japan via the “Plug & Play Japan” platform in 2026, North America from 2028.

Lead investor SHIFT Invest backs impact-driven industrial technology from the Netherlands. Returning co-lead Kvanted Ventures doubling down from the 2024 round is a clear signal of execution confidence. And angel Frank Höcker — founder of both PRESTO and Höcker Polytechnik — brings the kind of hands-on German industrial manufacturing credibility that matters when selling into factory floors.

The workforce angle matters too. Skilled NDT technicians are in short supply across Europe, and the shortage is structural. For manufacturers already grappling with labour constraints — a dynamic also evident in sectors from energy infrastructure to public transport IT — automation is no longer just a cost argument. It is a capacity argument. RESONIKS is building for exactly that moment.

RESONIKS is headquartered in The Hague, Netherlands, with offices in Tampere and Munich. More information at resoniks.com.

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