# Connector Click Sound Inspection: Verifying Fastening by Sound

Canonical URL: https://deeplyinc.com/cases/connector-click-sound-inspection
Language: en
Solution: industrial
Published: 2026-09-23
Last verified: 2026-09-23

Catch missed and partial fastening on the assembly line by sound instead of vision. Check whether each connector is fastened, and how many times, even at the underside where the eye cannot reach

## Classification

- Industry: Automotive & heavy equipment
- Process: Assembly
- Inspection target: Connector & bolt fastening
- Target sound: Connector fastening sound

## Overview

Listen AI recognizes the 'click' a connector makes when it is fully seated, and confirms both whether it was fastened and how many times. It catches by sound what vision inspection misses — missed fastening, fastening an operator overlooked, and fastening in places the eye cannot check, such as the underside. Deeply has deployed connector fastening sound inspection on the production lines of several global OEMs

## Customer Tasks

- Catch the missed fastening that vision inspection and operators overlook
- Confirm fastening at the underside and other hidden positions
- Count the fastenings made in one cycle
- Double-check bolt fastening faults that torque values alone miss

## Field Challenges

- Vision inspection could not detect fastening deep in places it cannot see, such as the underside of the car body. A connector could look fastened and still not be
- Parts located at the underside, such as hybrid connectors, were hard for operators to check by eye
- Even with vision inspection in place, the floor often did not trust its results right away. Limited customization by vision vendors and the difficulty of tracing the cause of a problem were raised again and again
- Torque tools measure torque and rotation angle, but torque can still read normal when a screw is cross-threaded, stripped, or broken. As long as the values matched, the part passed, and missed fastening slipped through

## Site Conditions and Constraints

- Assembly line mixing neighboring-process noise, drills, fan noise, and body resonance
- Several connector types on one line
- Fastening sound that varies with operator posture, microphone position, gloves, and fastening speed
- Two operators fastening at the same time
- Line running 24 hours in three shifts

## Deployment and System Setup

- Handheld or fixed acoustic sensors, chosen to suit the site
- Pickup directivity tuned to reduce recognition differences by microphone position
- Sensor mounted on the robot-arm gripper for robotic fastening
- Closed-network setup that analyzes at the edge and sends only results
- PLC integration by default, with results passed to existing MES and vision systems

## Outcomes

Key metric
- 99.87%: Connector fastening sound inspection accuracy (Definition: Accuracy of judging connector fastening from the fastening sound; Scope: Result on global automaker Company H production lines in Korea and Mexico; Source: Press release of June 11, 2026)
- 99.87%: Connector fastening sound inspection accuracy (Definition: Accuracy of judging connector fastening from the fastening sound; Scope: Result on global automaker Company H production lines in Korea and Mexico; Source: Press release of June 11, 2026)
- 19: Industrial site deployments (Definition: Deployments of connector fastening sound inspection and motor noise inspection combined)
- 100%: Higher inspection throughput (Definition: Twice the inspections in the same time as before)

## Measurement Conditions and Limitations

- Measurement conditions: In the OEM assembly-line review, recognition was validated on five connector types under normal, factory-noise, and drill-noise conditions
- Limitations: Recognition performance depends on connector type, line noise, and microphone placement. Each site is confirmed with a PoC first, and judgment criteria are agreed afterwards

## Related Pages

- [Listen AI Industrial](https://deeplyinc.com/solution/industrial)
- [Inquiry](https://deeplyinc.com/inquiry)

## Machine-Readable References

- [llms.txt](https://deeplyinc.com/llms.txt)
- [llms-full.txt](https://deeplyinc.com/llms-full.txt)