Smart Sensors and PocketCodr Combine to Eliminate Avoidable Scrap Costs During Nut Detection


In assembly operations, defective parts result in costly production scrap. Commonly, manufacturers use weld nuts to provide threaded mounting points in sheet-metal parts, but without robust sensing systems, missing weld nuts go undetected. Contrinex DMS Inductive Smart Sensors confirm the presence or absence of individual nuts in real time, reliably and repeatably. Using the hand-held PocketCodr configurator, configuring sensors for multiple panel variants is simple, requiring no coding expertise and no detailed knowledge of IO-Link.

Customer Application

In manufacturing operations, early detection of non-conforming parts and assemblies is key to avoiding downstream disruption. Failure to do so leads to costly downtime, rework and potential production scrap. Automated assembly processes, particularly in high-volume sectors that include automotive and white goods, require reliable detection systems that identify faulty items with a high degree of accuracy.

 Preformed steel panels that incorporate weld-nut fasteners are widely used in these industries. Weld nuts offer a low-cost, easily automated means of producing strong, threaded mounting points in relatively thin-gauge sheet-metal parts; a missing weld nut renders an assembly unusable, but may go undetected in the absence of an in-line detection system that operates in real time.

 Robotics engineers require sensor-based systems that sense the presence or absence of multiple weld nuts on a single panel, reliably and repeatably. Additionally, the ability to repurpose a test station to accommodate alternative parts and geometries, quickly and with minimal interruption to production, is highly desirable. Commonality of sensing components is a priority, ideally by using off-the-shelf intelligent sensors that can be reconfigured without high-level programming skills.

Customer Solution

DMS Inductive Smart Sensors from market-leading Swiss manufacturer Contrinex tick all the boxes for this type of application – particularly in combination with the innovative hand-held PocketCodr configurator. Multiple sensors, mounted in quick-change, adjustable fixtures, perform real-time measurements that confirm the presence or absence of individual nuts at predetermined positions on robotically loaded panels, initiating rejection of faulty units.

 M12 metal-bodied embeddable DMS Smart Sensors are compact yet robust; these IO-Link-enabled devices ensure highly accurate no-contact sensing, with operating distances up to 4 mm. Built-in delay and timer functions ensure that internal switching signals (SSC1 and SSC2) stabilize before enabling any alarm outputs, preventing false positives from triggering the rejection of good parts.

 Configuring sensors for panels of differing sizes and geometries is simple and swift, requiring no coding expertise and no detailed knowledge of IO-Link. The technician simply connects each sensor in turn to the PocketCodr device and uses the companion app installed on a smartphone or other mobile device to set and monitor the switching points. As a panel is presented, the measurement value is displayed together with the high/low status of one or more internal switching signals.

 The technician assigns the output switching signal (OSS1) to trigger on a user-defined condition – in this instance, when only SSC1 is high. Every aspect of configuration is driven by intuitive selection via the app, and on completion, the sensor is simply reconnected to the machine’s control system.

 IO-Link connectivity provides an easy interface to the central control system. After initial calibration, each sensor’s configuration is stored automatically on the local IO-Link Master; this allows plug-and-play replacement of sensors should the need arise, without any loss of functionality and without any need for recalibration. DMS inductive Smart Sensors, used in combination with PocketCodr, deliver value for money that is second-to-none.

Customer Values:

  • Robust DMS inductive Smart Sensors eliminate costly downstream scrap
  • Early detection of incomplete assemblies prevents avoidable interruptions to production
  • Built-in delay and timer functions prevent false positives from triggering the rejection of good parts
  • Innovative PocketCodr no-code sensor configurator simplifies configuration and minimizes costs of set-up
  • Individual device configurations are stored locally, allowing plug-and-play replacement of sensors when needed
  • Industry-standard IO-Link connectivity enables quick, easy integration to the machine control system for process data
  • Full-Inox sensors with one-piece V2A (AISI 304) stainless-steel housings are available for exceptionally harsh environments

Product Specific Values:

  • Robust, metal-cased inductive Smart Sensors are ideal for easy integration
  • Multi-channel monitoring circuitry allows users to define multiple customized output thresholds
  • Sophisticated sensing electronics deliver high-precision multi-mode measurements
  • Smart Sensors are individually shielded and EMC immune, eliminating interference when multiple devices operate in close proximity
  • Dedicated service-data blocks hold device-specific data including product ID, location and serial number
  • Industry-standard -25°C to +70°C operating range